DCOG/PMC RETRAITE 2015 SYLLABUS. 2 nd Retrait of Dutch Childhood Oncology Group and Prinses Maxima Centre for Pediatric Oncology

Transcription

1 DCOG/PMC RETRAITE 2015 SYLLABUS 2 nd Retrait of Dutch Childhood Oncology Group and Prinses Maxima Centre for Pediatric Oncology Hotel de Biltsche Hoek, de Bilt 19 & 20th of March

2 Introduction The Princess Máxima Center (PMC) for pediatric oncology aims to contribute to improving the treatment of childhood cancer with the following objectives: o >90% survival in 2025 o <50% incidence of late effects of treatment in 2025 The PMC aims to improve the outcome for these children by bringing together in one center the treatment and research expertise to create synergies that will accelerate progress in discovering and delivering cures. Research Vision: In the Research Institute of the PMC pre-clinical and clinical researchers work together on the most urgent patient-relevant topics. The choices of research topics are mainly determined by the relevance of the subject for the patient group. The most urgent patient-relevant issues will be particularly identified by development of evidence-based guidelines for treatment and follow-up, and by direct input from patients and parents. The (fundamental) tumor-biological research will also lead to new possibilities for patient application. With this annual retrait, we hope to have a forum for researchers, to exchange knowledge, to exchange idea s and to get inspired by people who are working in the same field, but maybe with different expertise. In the last months, many researchers have given input to give an overview about the current research in the PMC. This inspired also finetune our research vision, in collaboratorion with different partners. Hopefully, this meeting will add a new chapter to this. I wish you a fruitful meeting, leading to new research, as well as making a strong basis for the Research Institute of the PMC. Valérie de Haas 2

3 INDEX Page Program 4 Acute lymphoblastic leukemia 8 Lymphomas 47 Myeloid Malignancies 51 Solid Tumors 68 Brain tumors 86 Immunotherapy 97 Late Effects 112 Phase I-II studies 131 Oncogenomics 137 Supportive Care 145 Psycho-Oncology 166 Outreach 178 List of Participans 180 3

4 Final Program DCOG/PMC Retrait 2015 Thursday 19th of March u u u Welcome Valérie de Haas Acute Lymphoblastic Leukemia Frank van Leeuwen: Overview molecular research ALL 1. Kirsten Canté: Mousemodels in T-ALL 2. Mark Kerstjens: MEK inhibition is a Promising Therapeutic Strategy for MLL-rearranged Infant ALL Patients Carrying RAS Mutations 3. Laurens van der Meer: Reverse genetic screens using Crispr/Cas9 4. Roel Polak & Bob de Rooij: B-cell precursor acute lymphoblastic leukemia cells use tunneling nanotubes to orchestrate their microenvironment. 5. Lymphoma Auke Beishuizen: Overview Lymphoma 1. Jan Loeffen: Lymphoma & Genetics 2. Friederieke Meijer-Wentrup: Identification of pediatric Hodgkin Lymphoma biomarkers and novel therapeutics u u u u Quick Coffee/Tea, followed by. Rob Pieters: Update Research in PMC; subsequently discussion: Development of research in the PMC: how to organize? LUNCH BRAIN TUMORS Dannis van Vuurden: Pediatric Neuro-Oncology Research High Priority! 1. Avanita Prabowo: Characterization of genetic aberrations in pediatric low-grade glioneuronal tumors 2. Sophie Veldhuijzen Van Zanten: Molecular imaging in diffuse intrinsic pontine glioma 3. Walderik Zomerman: Kinome profiling of pediatric medulloblastoma 4. Lot Sewing: Liquid biopsies 4

5 u PSYCHO-ONCOLOGY Martha Grootenhuis: Overview Pediatric Psycho-Oncology Research 1. Sasja Schepers: From research to standard care: studying implementation of patient reported outcomes in pediatric oncology practice using 2. Raphaele van Litsenburg: The importance of studying Sleep u SUPPORTIVE CARE Marianne van de Wetering: Overview supportive care research 1. Wim Tissing: Preclinical research 2. Mischa Keizer: Efficacy of asparaginase on the complement system 3. Erik Loeffen: Significance of establishing supportive care guidelines 4. Hester Blufpand: Renal toxicity in pediatric oncology and ways of monitoring u u Coffee/Tea KIKA Tom Voûte Award 16.00u Introduction 16.15u Saskia Gooskens: TCF21 hypermethylation in genetically quiescent clear cell sarcoma of the kidney 16.30u Tim van Groningen: Neuroblastoma is biphasic with classical neuroepithelial cells and chemo-resistant mesenchymal cells controlled by PRRX1-NOTCH signaling 16.45u Saskia Hopman: The development of a clinical screening instrument for tumor predisposition syndromes in childhood cancer patients 17.00u Marieke de Ruiter: Neurofeedback in pediatric brain tumor survivors 17.15u Anna Wojtuszkiewicz: Alternative splicing in acute leukemia: the relevance for drug resistance and treatment u DRINKS 18.30u Announcement of winners Tom Voûte Award 19.00u DINNER 5

6 Friday 20 th of March u SOLID TUMORS Jan Molenaar: Overview Solid Tumors 1. Jan Koster: R2; a biologist friendly genomic analysis platform 2. Lieve Tytgat: MRD markers in Solid Tumors 3. Marc Wijnen: Surgical complications in Pediatric solid tumors 4. Marry van de Heuvel Eibrink: Overview research in Renal Tumors u MYELOID MALIGNANCIES Maarten Fornerod: Overview myeloid malignancies 1. Marije Bartels: The role of epigenetic regulators in chemotherapy resistance in pediatric AML 2. Nicole Larmonie: Methylation patterns in pediatric AML subgroups 3. Kim Klein: Translational research in Pediatric AML 4. Edwin Sonneveld: Molecular MRD in AML u u Coffee/Tea LATE EFFECTS Leontien Kremer: LATER: a nationwide collaboration 1. Ellen Kilsdonk: Late mortality in childhood cancer survivors : a DCOG LATER study 2. Marleen van den Berg: Reproductive function, ovarian reserve, and risk of menopause in female CCS VeVo DCOG LATER study 3. Lieke Feijen: Cardiac Disease in childhood cancer survivors: a DCOG LATER study 4. Eva Clemens: PanCare Studies in Fertility and Ototoxicity to improve Quality of Life After Cancer During Childhood u FASE I-II STUDIES Michel Zwaan: Overview fase I-II studies 1. Natasja van Eijkelenburg: MIBG-Gemcitabine in pediatric neuroblastoma patients 2. Sebastiaan Sassen: Towards evidence-based use of ciprofloxacin prophylaxis and glucocorticoids for children with cancer u LUNCH 6

7 u IMMUNOTHERAPY Jaap Jan Boelens: Overview Immunotherapy 1. Ingrid Brok: A transplantable tumor model to develop Immunocombination therapy of Neuroblastoma 2. Astrid van Halteren/Cor van den Bos: Langerhans Cell Histiocytosis targetting neo antigen-specific T cells in Langerhans Cel Histiocytosis 3. Maarten Schilham/Arjan Lankester: Natural Killer cell biology and immunotherapy 4. Rick Admiraal: Towards Predictable Immune-Reconstitution after Hematopoietic Cell Transplantation 5. Stefan Nierkens: WT-1 Cord Blood derived Dendritic Cell Vaccin for AML /Harmonized (Immuno)-monitoring protocols u OUTREACH Gertjan Kaspers: Introduction Dutch Outreach Pediatric Oncology 1. Trijn Israels: SIOP Africa/PODC Collaborative Wilms Tumour Project 2. Saskia Mostert: Adherence with childhood cancer treatment in Indonesia and Kenya u u u Keynote lecture Edwin Cuppen: Genome analyses within the Centre for Personalized Cancer Treatment Bill Evans: The St Jude Example Closing remarks 16.00u END of meeting 7

8 ACUTE LYMPHOBLASTIC LEUKEMIA 8

9 NAAM: Judith M. Boer Postdoc Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract: Key-words: pathobiology BCP-ALL, oncogenomics, data-integration, next-gen sequencing, bio-informatics Major breakthroughs in studying diseases can only be achieved by integration of multiple life science technologies in scientific research. We aim to discover novel abnormalities at the genomic, transcriptomic and proteomic level that have the potential to improve diagnostics and offer therapeutic targets in childhood ALL. Analyses of RNA expression as well as DNA copy number profiles, generated in our group and in others, have given valuable insights in molecular changes in childhood acute lymphoblastic leukemia (ALL). Our collection of different types of molecular profiling data from the same pediatric ALL patients now offers a unique opportunity to study the integrated effect of abnormalities at multiple omics levels simultaneously. We have developed a novel integration method that increases the discrimination between causative and bystander molecular changes. Our integration method is based on gene set testing to detect consistent effects across multiple genes with great sensitivity. We apply this systematic and unbiased approach to identify key genomic and mirna expression abnormalities that affect the expression and function of downstream genes in childhood ALL. Molecular abnormalities that affect downstream gene and protein expression are the most likely causative drivers of leukemogenesis. The embedding in a multidisciplinary research group ensures effective experimental validation of novel aberrations to answer these relevant biological and clinical questions in childhood ALL. 9

10 NAAM: Aurélie Boeree Technician Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: Pathobiology ALL, oncogenomics, drug interference studies, targeted drugs, ALL xenograft Work description I work as a technician in the group of Monique den Boer on the research laboratory of pediatric oncology. As technician we isolate leukemic cells from bone marrow and/or peripheral blood for further experiments. For example, I am testing patients leukemic cells for the presence of different tyrosine kinase gene fusions and whether these cells are sensitive to chemotherapeutic drugs and inhibitors. Together with dr. C. van de Ven I will soon start with a proof-of-concept study in mice. In vitro results show that the TCF3-PBX1 positive leukemic cells are very sensitive to the BTK inhibitor Ibrutinib. To rationally re-design therapies for this good prognostic group, more proof is needed. To this aim, we determine the anti-leukemic effect and specificity of the inhibitor in vivo. After an intrafemural injection with patients leukemic cells the mice develop leukemia. Subsequently, these mice are treated with Ibrutinib and the antileukemic effect is being monitored by measuring the amount of human leukemic cells in the blood of the mouse and by determining the effect of Ibrutinib on downstream effectors of BTK. 10

11 NAAM: Prof.dr. Monique den Boer hoofd researchlaboratorium, principal investigator Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all Key-words: Pathobiology B-cell precursor ALL, oncogenomics, BCR-ABL1 like ALL, subclonality of disease, predictive biomarkers, drug resistance mechanisms, microenvironment, targeted drugs, ALL xenografts, humanized scaffold models, early clinical trials, translational research, personalized medicine. The major aims of Monique s research program Molecular Markers and Targets are: 1) To decipher the pathobiology of ALL in order to find new molecular markers (at DNA, RNA and/or protein level) that can be used for a better risk stratification and application of personalized medicine (targeted drugs) in pediatric B-cell precursor ALL. 2) To study the leukemic niche in order to circumvent microenvironmental induced quiescence of leukemic cells and escape from chemotherapy. Main topics that are being studied: oncogenomics of B-other, BCR-ABL1-like and known cytogenetic subtypes. Finding mutations/genetic abnormalities in leukemic cells and study the clinical relevance of these lesions and synergy with recurrent cytogenetic lesions in the right cellular context. causes of cellular drug resistance and how to sensitize to chemotherapeutic drugs, mainly focused on glucocorticoids and L-asparaginase. subclonality of leukemia and how to eradicate these subclones more effective. interaction between leukemic cells and the bone marrow microenvironment and how to interfere with this niche to prevent outgrowth of resistant subclones. exploring drugable targets and targeted drugs (including mouse models) and provide an evidence-based rationale for predictive biomarkers and eligibility criteria to select patients for early clinical trials. 11

12 NAAM: Miriam Butler Promovendus Naam Centrum: Radboud umc Naam Research groep: Laboratory of Pediatric Oncology Abstract Although it is now possible to predict poor response based on tumor genetics, translating this into alternative therapeutic strategies remains a challenge. For example, loss of IKZF1 predicts a poor outcome. Similarly, deletion of BTG1 is associated with a poor response in a subgroup of patients. How the genetic lesions that are associated with poor outcome affect the cellular response to chemotherapy, is currently unknown. We combine the overexpression of oncogenes with RNAi or CRISPR/Cas9 based loss-offunction of tumor suppressors to model a relevant genetic context in both cell line as well as mouse models. Using this approach, we have successfully induced resistance towards the tyrosine-kinase inhibitor imatinib by generating a genetic knockout of NF1, a member of the RAS pathway. Next, we aim to define the molecular pathways that are altered in the modeled resistant cells using both biochemical studies (looking for pathway activation) as well as expression analysis (expression arrays). Alternatively, because not every poorly responding can be identified using genetic stratifiers, we are performing an unbiased genome-wide CRISPR/Cas9 based loss and gainof-function screen to identify pathways that can be linked to therapy resistance. These combined approached will not only lead to more insight into the mechanisms of therapy resistance in pediatric ALL, but can identify potential therapeutic targets that can be exploited in a strategy to overcome resistance. 12

13 NAAM: J.G.C.A.M. Buijs-Gladdines Research Analist Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam-Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Abstract Key-words: T cell-acute Lymphoblastic Leukemia, support of PhD students and postdocs, Whole genome sequencing project, patient care I am working since 2001 as a research technician at the T-ALL group led by Dr. J.P.P. Meijerink. As a research technician, I especially support the PhD students and postdocs in our group. In these 14 years, I have gained a lot of experience in various cellular and molecular techniques such as DNA / RNA isolation, FISH (self-optimized in our department), ELISA (RTQ) PCR, sequencing, array CGH, DNA microarray, flow cytometry, western blotting, hybridoma technology, recombinant protein production and isolation and cell culture. By gaining these experiences, I joined a few years to become chief technician within our group. The project, for which I currently offer support, is the Whole genome sequencing project together with Yunlei li (Bioinformatician within the T-ALL group). For this project, we hope to find by means of High through-put sequencing, new genes, which may be important in the development of T-ALL and possibly important new targets for the development of a targeted therapy. High through-put sequencing was carried out on DNA from both diagnosis and remission material of a large cohort of T-ALL patients. Based on the results we are now working with functional validation experiments found to be able to prove functional associations. In addition to the research, I am also involved in the reprocessing of patient material. During this procedure, the blasts from the bone marrow and / or blood of leukemia patients will be isolated, characterized and viable frozen, which can be used for various research questions. 13

14 NAAM: Kirsten Canté-Barrett, PhD Postdoc Naam Centrum: Erasmus MC, Rotterdam Naam Research groep: T-ALL (Dr. J.P.P. Meijerink) Research interesses/expertises (trefwoordsgewijs, max.50 woorden): Early T cell progenitor ALL (ETP-ALL) Xenografting human (leukemic) cells in immunocompromised mice Knock-out and Knock-in mouse models Relating T-ALL oncogene function to normal T cell development Beschrijving eigen research project Pediatric T-cell acute lymphoblastic leukemia (T-ALL) is a cancer of developing T-cells in the thymus. Genetic aberrations can lead to oncogenic transformation and differentiation arrest of thymocytes. Transformed thymocytes acquire pathogenic mutations that further contribute to uncontrolled thymocyte expansion and T-ALL, therapy resistance and relapse. T-ALL subgroups are classified by the activation of oncogenes that facilitate T-cell developmental arrest. Our group identified a novel genetic T-ALL subgroup that overexpresses the transcription factor MEF2C and that is associated with the high-risk early thymocyte progenitor ALL (ETP-ALL). Moreover, my work using Mef2c conditional knock-out mice points to an important role for MEF2C in normal T-cell development, and deletion of this gene early in T-cell development results in severely reduced T-cell numbers. To further prove MEF2C as a pathogenic driver for ETP- ALL, we have developed a conditional transgenic knock-in mouse model in which the human MEF2C gene can be activated exclusively and ectopically in early developing thymocytes. Preliminary results again demonstrate T-cell developmental defects by arresting differentiation of early thymocytes. Current aging cohorts and bone marrow transplantation experiments are ongoing to model MEF2C-driven T-cell leukemia. We further aim to compare gene expression signatures and immunophenotype of mouse leukemia cells with primary leukemia cells from ETP-ALL patients to pionpoint conserved pathogenic mechanisms of MEF2C. This way, we aim to identify potential drug targets for future patient-tailored therapies for ETP-ALL. This system can be exploited as a novel in vivo model to study MEF2C-driven ETP-ALL and in-vivo drug-testing. 14

15 NAAM: Patricia GARRIDO CASTRO Postdoc Naam Centrum: Erasmus MC Sophia Kinderziekenhuis Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, mirna expression, bone marrow microenvironment, xenograft mouse model, in vivo pre-clinical drug testing. Abstract Both biologically and clinically, MLL-rearranged infant acute lymphoblastic leukemia (ALL) represents a unique malignancy associated with drug resistance to first-line chemotherapeutics, high relapse rates and an unfavorable prognosis. Hence, novel treatment strategies that specifically target the underlying molecular pathobiology of this disease are urgently needed. The majority of the MLL rearrangements involve the translocation partners AF4, AF9 or ENL; the resulting fusion genes, MLL/AF4, MLL/AF9 and MLL/ENL, code for chimeric transcription regulators acting as strong oncogenic drivers, rewriting the epigenetic landscape of the cell and profoundly altering gene expression. In order to gain further molecular understanding, we have already performed patient cohort profiling on both the transcript and epigenetic level. Currently we are completing mirnome screens of primary patient material, as well as hematopoietic precursor cells transduced to ectopically express the MLL fusion genes. This comprehensive approach reveals molecular events associated with MLL fusions on different regulatory levels, highlighting aberrant pathways and networks as putative novel druggable targets. Furthermore, we have established an in vivo xenograft mouse model with MLL-rearranged cells, able to recapitulate the disease observed in humans. Investigating the interactions of these leukemic cells with their microenvironment and how they influence each other on a molecular level, unveils novel points of attack. Consequently, candidate drugs targeting MLL-rearranged ALL cells or their interactions with the microenvironment are tested using this in vivo model. This integrative research approach, including both fundamental target discovery and translational pre-clinical in vivo models, aims to generate novel treatment rationales for this hard to treat disease. 15

16 NAAM: Willemieke de Goffau Nobel Technician Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: Pathobiology ALL, oncogenomics, drug interference studies, fusion genes, targeted drugs. Patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) can be classified in several subtypes, based on their genetic background. Unfortunately, certain cytogenetic subtypes are still associated with a poor prognosis. The overall survival of pediatric BCP- ALL is around 80%. We have identified patients carrying JAK2 mutations or JAK2 rearrangements by Sanger sequencing and RT-PCR/FISH, respectively. Mutations and rearrangements are thougth to activate the JAK-STAT signaling pathway, resulting into survival and proliferation of these leukemic cells. Currently, we are investigating the efficacy and specificity of two JAK2 inhibitors, momelotinib and ruxolitinib, on cell lines and patients leukemic cells. These inhibitors are tested in leukemic cells which are grown in co-culture with mesenchymal stromal cells, since stromal (growth) factors may be essential to (co) activate the JAK- STAT pathway. We compare patients samples with and without the presence of these fusion genes or mutations. Our aim is to identify which JAK2 inhibitor may be most specific against JAK2-aberrant cells, whether JAK2-mutated cells respond different to these inhibitors than JAK2-translocated cells and how these inhibitors affect the response to regular chemotherapeutic drugs (e.g. to prednisolone). 16

17 NAAM: Y.M. van Helsdingen Researchanalist Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam- Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Abstract Als researchanalist in de T-ALL groep van de afdeling kindergeneeskunde, hou ik mij voornamelijk bezig met lentivirale gentherapie technieken om muis stamcellen te transduceren met genexpressie constructen om T-ALL oncogenen geforceerd tot expressie te kunnen brengen. Middels dit model bestuderen we de impact van deze oncogenen op normale T-cel ontwikkeling in de muis alsook het ontstaan van T-ALL na in vivo transplantatie experimenten. Daarnaast willen we synergisme van afwijkingen die vaak gepaard voorkomen in T-ALL patiënten bestuderen in het ontstaan van T-ALL. Middels dit model systeem proberen we meer te weten te komen over de pathogenetische mechanismen van oncogenen waardoor T-ALL ontstaat en waarop we nieuwe therapie zouden kunnen richten. Daarnaast kunnen deze modelsystemen helpen om de effectiviteit van nieuwe middelen (compounds) te testen. Tot mijn dagelijkse werkzaamheden behoren o.a. ook genotyperingen van de muizenlijnen, het produceren van lentivirale virus batches, het isoleren van muis stamcellen en transductie, RNA/DNA isolaties van patiëntmateriaal, kweken van T-ALL cellijnen. Hiervoor gebruik ik diverse technieken zoals o.a. DNA/RNA isolaties, (RTQ)PCR, virusproductie en transductie, kloneren van nieuwe constructen op basis van de Gateway technologie, FACS analyse en cel sorteringen, western blot en diverse dierexperimentele technieken (oogsten van cellen uit muis beenmerg, diverse injectie technieken, etc). 17

18 NAAM: Alex Hoogkamer Bioinformaticion Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: pathobiology BCP-ALL, oncogenomics, mutation analysis, subclonality of disease, next-gen sequencing, data-integration, bio-informatics Pediatric leukemia is the most common cancer diagnosed in hundred-fifty children each year in the Netherlands. Using techniques such as next generation sequencing we aim to find (sub)clonal mutations in known oncogenic genes such as RAS, RAF and P53. We are sequencing a cohort of over 500 patient samples on the Illumina Miseq platform with 1000x coverage of a custom cancer gene panel in collaboration with the Center for Personalized Cancer Treatment (CPCT). One of the challenges of next generation sequencing is the processing of data. We work on creating bioinformatics workflows that take raw sequencing reads and transform it into a comprehensive and human readable format. This workflow includes quality control, mapping of sequencing reads back to the human genome, variant calling and filtering of the found mutations. A second line of bioinformatics research involves the integration of different types of highthroughput 'omics' data such as mutations, DNA copy number, gene expression and protein expression levels. By integrating these different types of data we prioritize genes and proteins for experimental validation and functional studies in the lab with the aim to identify markers to improve diagnostics and targets for novel treatment strategies. 18

19 NAAM: Peter Hoogerbrugge Klinisch-projectleider Naam Centrum: Naam Research groep: Prinses Máxima Centrum Lab Pediatric Oncology Nijmegen Abstract See summary lab Dr Frank van Leeuwen. In collaboration with the groups of Prof. Den Boer (ErasmusMC, Rotterdam), DCOG (Drs De Haas and Sonneveld) and Dr. R Kuiper (Human genetics, RadboudUMC), research aimed at improving early identification of ALL-patients at high risk for relapse by using the latest genome-analysis techniques is being performed. The mechanisms of the therapy-resistance in these patients is being performed in-vitro and in murine models, e.g. of IKZF-deleted leukemias. The aim of this line of research is developing targeted, more effective treatment. In another line of research in collaboration with Prof. Adema (Tumorimmunology dept, RadboudUMC) relevant murine models of high-risk Neuroblastoma are being used to improve immunotherapy for patients with high-risk neuroblastoma. We focus on the development of more effective, rational combined immunotherapy-chemotherapy regimens. 19

20 NAAM: Adrián Jaramillo Promovendus Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, MLL-AF4 driven leukemogenesis, MLL-AF4 dependent genes. Abstract : My research work on MLL-rearranged acute lymphoblastic leukemia in infants includes: 1. The contribution of the bone marrow niche to leukemogenesis, and 2. Validation and characterization of genes transcriptionally dependent on the presence of the MLL fusion protein. 1. Despite the aggressive nature of MLL-rearranged infant ALL, it remains difficult to model leukemogenesis in mice by xenotransplanting human hematopoietic stem cells (HSCs) expressing the MLL-AF4 fusion gene. Recent studies have showed that a unique feature of MLL-AF4+ infant ALL is the presence of the MLL-AF4 fusion in the patient s bone marrow mesenchymal cells. This may suggest that a leukemic bone marrow microenvironment may be required for proper transformation. Therefore we are currently conducting experiments in mice in which MLL-AF4 expressing human mesenchymal stem cells (MSCs) are co-injected together with MLL-AF4+ human HSCs. 2. Recently our research group has identified gene signatures that transcriptionally readily respond to sirnamediated knock-down of MLL-AF4. Obviously, these genes potentially represent attractive therapeutic targets. Therefore we are currently in the process of validating and functionally characterizing the effects of gene expression modulation of a selected subset of these genes with respect to drug resistance, proliferation and leukemic cell survival. 20

21 NAAM: Isabel Jerchel PhD student Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: pathobiology BCP-ALL, oncogenomics, subclonality of ALL, microenvironment, growth factor mediated signaling, cellular drug resistance, targeted drugs. Most pediatric patients with B-cell precursor (BCP) ALL have a good prognosis: the overall survival rate has improved to 80-90%. For certain subgroups of patients the cure rates are considerably lower. Most relapses occur in patients who have been in complete remission for several months up to years and ALL cells from relapsed patients are often intrinsically more resistant to chemotherapy. It is therefore believed that a small number of drug resistant cells can survive chemotherapy and grow out to a relapse. The bone marrow microenvironment that usually supports normal hematopoiesis, is believed to play an important role in supporting the survival of ALL cells: by providing nutrients and growth factors the bone marrow stroma forms a home for the leukemic cells. Our research therefore aims to discover and target the factors and pathways that link the bone marrow stroma to the ALL cells. Interfering with this supportive niche may reduce the amount of chemotherapy needed to eradicate all leukemic cells and may also prevent that resistant subclones reside in the bone marrow during chemotherapy. Furthermore, several recurrent genetic aberrations in growth factor receptors and their associated pathways are indicative of a trend towards niche independence, highlighting the importance of the growth signals initially regulated by the niche. In line with this, our group has recently shown that activating RAS mutations confer cellular resistance towards prednisolone. Importantly, RAS is a cellular hub for relating external growth factor signals into a cellular growth response. In an ongoing study we currently study the subclonality of BCP-ALL for RAS-pathway genes and other candidate genes which are often mutated in other malignancies. To this aim, next generation sequencing (Illumina, MiSeq, paired-end sequencing) of ALL samples is being performed and patients are selected for functional studies addressing the specificity of targeted drugs in combination with prednisolone. Our aim is to elucidate the signal mediators that activate survival pathways, which may lead to drugs/inhibitors which block the vital growth signals and may be of use to kill (subclones of) leukemic cells more specifically. 21

22 NAAM: Mark Kerstjens Promovendus Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, drug library screening, pre-clinical in vivo drug testing. Abstract MLL-rearranged acute lymphoblastic leukemia (ALL) in infants (<1 year of age) remains one of the most aggressive and difficult to treat types of childhood leukemia. Consequently, the survival chances for these very young patients are still very poor (i.e. EFS rates of only 30-40%). Clearly, there is a dire need of new and improved therapeutic strategies and more adequate therapeutic agents. Although target-based drug design is a valid approach, and has resulted in the discovery of promising small molecules by our group and others, the transition from pre-clinical investigation towards clinical application remains a timeconsuming process. Therefore we have employed a drug library screening approach, focusing on FDA approved drugs and small molecule inhibitors under clinical investigation, in order to more efficiently identify clinically readily applicable therapeutic candidates. Our efforts resulted in selection of a subset of promising compounds, which have been further validated for anti-leukemic potential in different cell line models and on primary material. The most potent and efficacious drugs are currently being validated in an in vivo mouse model. Furthermore, characterization of the molecular mechanisms that underlie the effectivity of these inhibitors is also in progress. 22

23 NAAM: Frank van Leeuwen Laboratoriumhoofd Naam Centrum: Radboudumc Naam Research groep:laboratorium Kinderoncologie Abstract Dr. Frank N. van Leeuwen is associate professor at the Radboudumc and head of the Laboratory of pediatric oncology. His research focuses on the cell biological and genetic characterization of childhood cancer, aimed at improving diagnosis and treatment. His group (8 fte) applies in vitro as well as in vivo experimental approaches to model genomic abnormalities in pediatric Acute Lymphoblastic Leukemia (ALL). Examples include interactions between ETV6-RUNX1 and the tumor suppressor BTG1 and those between oncogenic tyrosine kinases and the B-cell transcription factor IKZF1. In addition, his group studies mechanisms of therapy resistance to chemotherapeutic agents such as prednisolone and asparaginase and the role of cellular stress pathways therein. A second line of research involves mechanisms of invasion and metastasis in solid tumors, particularly neuroblastoma. Frank van Leeuwen is an active member of the DCOG study group on Molecular Research, member of the international study group for treatment of relapsed ALL (IntReALL) and chair of the KWF Society for Tumor Cell biology ( 23

24 NAAM: Yunlei Li Postdoc Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam-Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Research interesses/expertises : Pattern recognition, Bioinformatics, Next generation sequencing, Integration of highdimensional datasets, Oncology, T-cell acute lymphoblastic leukemia Abstract T-cell acute lymphoblastic leukemia (T-ALL) in children is considered as a high risk disease entity. To improve efficacy of current treatment regimens and to diminish late treatment effects, we aim to identify novel gene mutations in a genome-wide search in T-ALL patients that are linked to the pathogenesis of this disease and therapy resistance. In addition, we develop novel bioinformatics tools integrating high-dimensional datasets including mutation data, copy number aberrations, structural variations, ChIP-seq data, and genome wide gene expression profiles in order to identify aberrantly activated signal transduction pathways or genetic networks. We performed whole genome sequencing (WGS) on 13 representative pediatric diagnostic T-ALL tumour samples in comparison to their MRD-negative remission pairs. To focus on somatic protein-altering mutations, we employed a novel and rigorous selection strategy and used Sanger PCR sequencing to prioritize high-confidence mutations. Recurrence of mutations and their associations to biological and clinical parameters was determined by performing a targeted exome sequencing (TES) on a series of samples from 69 welldocumented T-ALL patients. For 53 cases, array-cgh data were obtained. We exploited the overlapping exonic non-synonymous mutations that are detected by both WGS and TES in the 13 tumors to determine high-confidence mutations detected by TES. Recurrent mutations/rearrangements affecting the steroid receptor and the interleukin 7 receptor signaling pathway were found associated with therapy resistance. A direct effect of these mutations on increased cellular resistance to therapeutic drugs was demonstrated in functional assays. The JAK inhibitors Ruxolitinub was shown to revert cellular resistance towards various chemotherapeutic drugs in T-ALL cells. 24

25 NAAM: René Marke Promovendus Naam Centrum: Radboud umc Naam Research groep: Laboratory of Pediatric Oncology Abstract: Role of tumor suppressor IKZF1 in leukemia outgrowth and chemotherapy resistance Children with acute lymphoblastic leukemia are stratified into risk groups based on specific diagnostic features, including age, WBC counts, immunophenotype and cytogenetics. Recently, we and others have shown that IKZF1 (IKAROS) gene deletions and mutations predict poor outcome in children with B cell precursor ALL (BCP-ALL), and IKZF1 gene alterations have now been incorporated in risk stratification of Dutch BCP-ALL patients. However, it remains to be established whether loss of IKZF1 function has a direct impact on chemotherapy responses. Furthermore, the effect of other genetic aberrations on therapy outcome of IKZF1-deleted has not been fully addressed. Therefore, the aim of my project is to obtain a detailed understanding of the molecular mechanisms by which IKZF1 and other co-occuring genetic events contribute to the pathogenesis of childhood ALL as well as the outgrowth of drug-resistant clones. Our recent data demonstrate that IKZF1 is a key determinant in regulating glucocorticoid(gc) responses in B-cells. We established that Ikzf1 +/- B-cells, leukemia cell lines with silenced IKZF1 expression, and primary BCP-ALL samples with IKZF1 gene alterations display resistance against GC-induced apoptosis. Currently, we are investigating the molecular mechanism of GC therapy resistance through loss of IKZF1 function. In addition, we are implementing different models to explore the genetic interaction between IKZF1 and other genetic defects (i.e. BCR-ABL1, BTG1) in leukemia initiation and chemotherapy responses. This will provide us a rationale for (i) tailored chemotherapy strategies in ALL and (ii) defining candidate molecules for targeted therapies as alternative treatment modalities. 25

26 NAAM: Laurens van der Meer Postdoc Naam Centrum: Radboud umc Naam Research groep: Laboratory of Pediatric Oncology Abstract Cell intrinsic molecular mechanisms of therapy resistance Genetic characterization of pre-b acute lymphoblastic leukemia has allowed the identification of mutations that are predictive of outcome. Although some lesions are linked to a high change of developing relapse and associated therapy resistance, how these lesions alter cell behavior is largely unknown. We aim to identify molecular pathways that control drug sensitivity by modeling the genetic alterations that confer resistance in tumor cells. Together with PhD student Miriam Butler, we have introduced both targeted and genome-wide CRISPR-Cas9 based modeling of gene expression and we will apply this technology to engineer relevant genetic lesions in our model cell line, mouse and human B cell progenitors as well as patient derived cells. Host mechanisms of therapy resistance Asparaginase is an essential drug in the treatment of pre-b ALL. Large inter-patient differences in drug kinetics and development of adverse (immune-)reactions are poorly understood and pose a threat to the therapeutic efficacy of this drug. We have applied in vivo imaging using radio-labeled asparaginase to identify the cells that contribute to asparaginase clearance. In addition to the expected liver and spleen, we identified a strong accumulation of asparaginase in the bone marrow. We found that bone marrowresident macrophages specifically bind and degrade asparaginase. This may protect tumor cells from its therapeutic function. Current efforts are aimed at identifying macrophagespecific cell surface molecules that allow binding, internalization of asparaginase, findings that may aid in optimization of Asparaginase therapy. 26

27 NAAM: J.P.P. Meijerink Groepsleider Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam-Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Keywords: T-cell acute lymphoblastic leukemia, T-cell non-hodgkin s lymphoma, pathogenesis, oncogenes, relapse mechanisms, therapy resistance mechanisms, selection of drugable targets, compound testing, Whole genome sequencing, genome-wide screening techniques for LOH, genomic breakpoints, leukemia mouse models, patient-derived xenograft models, T-cell development Abstract In 2000, I founded the T-ALL research group as project leader in the Department of Pediatric Oncology/Hematology of the Erasmus MC Rotterdam. In 2007, I was appointed UHD at this University Medical Center. Current research focus is to: 1. Identify pathogenetic drivers of (relapsed) T-ALL by high-resolution screening techniques and clinical implications. 2. Improve our understanding of leukemogenic pathways, with a current focus on the pathogenic role of MEF2C in ETP-ALL. 3. Better understand mechanisms of (acquired) therapy resistance in T-ALL and relapsed T-ALL 4. Identify molecular targets for future therapeutic intervention, and to provide preclinical evidence for the effectiveness of new therapeutic compounds using genetically modified cell line-based and patient-derived leukemia (xenograft) models. As knowledge on pathogenetic drivers for T-ALL is increasing, the current and future research focus is to elucidate pathogenic mechanisms of oncogenes and mutations in signal 27

28 transduction pathways. Better understanding of pathogenic mechanisms or synergism between mutated pathways will reveal potential targets for therapeutic intervention. For this, new compounds are required that need to be validated on T-ALL disease models upfront of clinical trials. These compounds are pivotal in reducing treatment intensity at disease presentation without compromising or improving the cure-rate for this disease while reducing severe late side-effects of current therapy for cancer survivors. To test compounds in relevant disease models in-vitro and in-vivo, we initiated the development of T-ALL disease models including OP9-DL1 stromal support cultures, development and characterization of conditional oncogene knock-in mouse strains, bone marrow transplantation assay using lentiviral expression vector-transduced stem cells and patient derived xenograft models that need to be further developed. Once relapsed, the outcome for T-ALL patients is very poor. We will also improve our understanding of disease relapse, possibly as consequence of selection of specific disease subclones during treatment as well as the development of targeted approaches to circumvent acquired therapy resistance. Further research will further be initiated on the pathogenic mechanisms and the development of patient-tailored therapeutic approaches for T-cell non-hodgkin s lymphoma (T-NHL) and anaplastic large T-cell lymphoma (ATL). The current researchgroup includes 2 postdocs (Dr. Kirsten Cante-Barrett en Dr. Eric Vroegindeweij), 1 bioinformatian (Dr. Yunlei Li), 3 technicians (Ing. Jessica Buijs- Gladdines, Ing. Wilco Smits, Ing. Yvette van Helsdingen) and 1 PhD-student (Drs. Rui Mendes) 28

29 NAAM: Femke Meijers Technician Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: pathobiology ALL, microenvironment, drug resistance, cell-cell communication, migration of leukemic cells. Work description: I work as a technician in the group of dr. Monique den Boer. I support the PhD students and postdocs by processing primary cells obtained from patients, both leukemic cells and mesenchymal stromal cells, and perform functional studies to unravel the pathobiology of ALL. Currently, I am working together with Bob de Rooij to study the function of Tunneling NanoTubes (TNT). Leukemic cells form TNTs with mesenchymal stromal cells (MSCs) in the niche of the bone marrow. We demonstrated that TNTs are used to bi-directionally exchange information which might be of importance for the leukemic cell to survive in these bone marrow niche. Moreover, it is known that leukemic cells can be resistant to certain types of drugs by which patients are treated. Our theory is that the interaction of the leukemic cell with the MSC by these TNTs is of importance to gain resistance. Blocking the TNTs could sensitize these cells for the drugs they are resistant to. At this moment we are performing a drug screen to search for possible inhibitors of these TNTs. 29

30 NAAM: Sandra Sofia Mimoso Pinhancos Research Technician Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, xenograft mouse model, bone marrow microenvironment, in vivo pre-clinical drug testing. Abstract: MLL-rearranged acute lymphoblastic leukemia (ALL) in infants (<1 year of age) is one of the most aggressive and difficult to treat types of childhood leukemia. Despite recent advances most infants (>60%) relapse on treatment with bone marrow (BM) as primary site of relapse, representing also the primary cause of death. A likely contributing factor to the poor prognosis is cellular drug resistance to multiple chemotherapeutics currently used in ALL treatments regimes. Earlier attempts to improve prognosis by increasing treatment intensities turned out to be unsuccessful. Therefore, novel and more effective therapeutics are urgently needed to adequately treat these patients. As a research technician I was involved in the establishment of an in vivo xenograft humanized mouse model for MLL-rearranged ALL in our laboratory, able to recapitulate the disease observed in humans. This model allows us to investigate the molecular interactions between the bone marrow microenvironment and leukemic cells, believed to substantially contribute to therapy resistance. Moreover, this xenograft model facilitates in vivo testing of candidate drugs targeting MLL-rearranged ALL cells or their interactions with the microenvironment. This research approach, including both fundamental target discovery and translational preclinical in vivo models, aims to generate novel, pre-clinical treatment rationales for this difficult to treat disease. 30

31 NAAM: Rui Daniel Mendes Promovendus Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam- Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Keywords: ETP-ALL, MEF2C, in vitro T-cell development, lentiviral gene delivery Abstract Pediatric T-cell acute lymphoblastic leukemia (T-ALL) is a cancer of developing T cells in the thymus. The T-ALL subtypes are characterized by ectopic expression of oncogenes type A aberrations - capable of arresting leukemic cells at different T cell developmental stages. The maturational arrest generates a premalignant condition that facilitates the acquisition of additional genetic hits, known as type B mutations. Based on gene expression signatures and detailed molecular-cytogenetic profiles our group identified an immature subtype, which is characterized by an early T-cell precursor (ETP) profile and rearrangements that activate the MEF2C oncogene. In order to investigate the role of this transcription factor and associated cofactors (e.g. LMO2, LYL1) in leukemic transformation we established the in-vitro OP9-DL1 T-cell development model from umbilical cord blood stem cells that may mimic normal human T-cell development in the thymus. We first validated normal T-cell development in this system in comparison to in-vivo human and mouse T-cell developmental stages as distinguish by specific T-cell markers. For this, we performed gene expression on sorted several OP9-DL1 T-cell stages based on the successive acquisition of early (CD7, CD5, CD1a) and late (CD4 and CD8) T- cell surface markers over 28 days of co-culture. Comparison of our in vitro gene expression data with mouse and human in-vivo data demonstrates high conservation of transcriptional programs during T-cell differentiation with conservation of the T-cell commitment checkpoint as biggest transcriptional change between early thymocyte precursor (ETP) stages and T-cell committed stages that is characterized by the expression of T-cell receptor and accessory molecules. We then investigated to what extend MEF2C or its cofactors LMO2 or LYL1 could disturb T-cell development. For this, umbilical cord blood stem cells were efficiently transduced by optimized lentiviral expression constructs that drive the expression of these genes in a constitutive manner. Expression of MEF2C and it s co-factors led to an arrest of developing T-cells at pre-commitment stages as observed in immature T-ALL. This system therefore provides suitable models to further investigate the oncogenic mechanisms of MEF2C and its co-factors in driving cellular arrest at the ETP stages that leads to ETP-ALL. 31

32 NAAM: Denise Niewerth Postdoc Naam Centrum: VU Medisch Centrum Naam Research groep: Kinderoncologie/Hematologie Abstract Application of bortezomib in pediatric acute lymphoblastic leukemia 32

33 NAAM: Roel Polak PhD student Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: pathobiology BCP-ALL, ETV6-RUNX1 positive ALL, autophagy, microenvironment, cell-cell communication, targeted drugs. Despite the advances made in the treatment of pediatric acute lymphoblastic leukemia (ALL) over the last decades, drug resistance and relapse of leukemia remain a large problem in the field. In this project, we aim to characterize and target leukemia-specific processes, including the contribution of the leukemic microenvironment, in order to find synergistic treatment strategies and thereby improve therapy of pediatric ALL. An example of recent work: Autophagy Inhibition as Targeted Therapy for ETV6-RUNX1 driven BCP-ALL. Translocation t(12;21), resulting in the ETV6-RUNX1 fusion protein, is present in 25% of pediatric patients with B-cell precursor (BCP)-ALL and is considered to be a first hit in leukemogenesis. To identify the molecular mechanisms underlying ETV6-RUNX1 driven leukemia, we performed gene expression profiling of healthy hematopoietic progenitors in which we ectopically expressed the ETV6-RUNX1 fusion protein. Using this approach, we revealed a transcriptional network that positively regulates proliferation, survival and cellular homeostasis. In addition, Vps34, an important regulator of autophagy, was found to be up-regulated in ETV6-RUNX1 positive BCP-ALL patient cells. This induction was transcriptionally regulated by ETV6-RUNX1 and correlated with high levels of autophagy. Pharmacological inhibition of autophagy with hydroxychloroquine reduced cell viability in both BCP-ALL cell lines and primary patient-derived BCP-ALL cells and selectively sensitised ETV6-RUNX1 positive leukemic cells to L-asparaginase. These findings reveal an important role for autophagy in ETV6-RUNX1 positive BCP-ALL and provide the first preclinical evidence for the efficacy of autophagy inhibitors in ETV6-RUNX1 driven leukemia. 33

34 NAAM: Bob de Rooij PhD student Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract Key-words: pathobiology BCP-ALL, microenvironment, drug resistance, cell-cell communication, targeted drugs Acute lymphoblastic leukaemia (ALL) cells reside in the bone marrow microenvironment, which nurtures and protects cells from chemotherapeutic drugs. Therefore, the disruption of this leukaemic cell-niche interaction is considered as a promising new therapeutic strategy. A major gap in our knowledge is the lack of insight into the functional mechanism regulating and controlling this crosstalk. My project aims to investigate the interactions between leukaemic cells and mesenchymal stromal cells, a prominent cell type in the bone marrow. We are developing novel approaches to disrupt the leukaemic microenvironment and prevent the preservation of residual leukaemic cells after chemotherapy treatment. Recently, tunnelling nanotubes (TNTs), or membrane nanotubes, have been described as a novel mode of communication between eukaryotic cells. These thin intercellular membrane conduits have been observed in several cell types, complex tissues and organisms, and facilitate the transport oseveral types of cargo. The presence of TNTs within the leukaemic niche and their role in leukaemic cell survival and drug resistance within this microenvironment are unknown. We show for the first time that tunnelling nanotube signalling occurs between leukaemic cells and mesenchymal stromal cells. Importantly, this signalling is essentially one-way: leukaemic cells use tunnelling nanotubes to orchestrate their microenvironment by directing non-malignant stromal cells to produce pro-survival cytokines. This process is important for leukaemic cell survival and induces stroma-driven prednisolone resistance. Disruption of tunnelling nanotubes significantly inhibits these leukaemogenic processes and re-sensitizes B-cell precursor-all cells to prednisolone. Our findings establish tunnelling nanotubes as a key communication mechanism by which B-cell precursor-all cells modulate their bone marrow niche. This observation gives insight into the pathogenesis of ALL and opens new avenues to develop more effective therapies that interfere with the leukaemic niche. 34

35 NAAM: Eddy van Roon Postdoc Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, MLL-AF4 driven leukemogenesis, fetal liver HSCs, in vivo mouse model, exome sequencing. Abstract: Chromosomal translocations involving the Mixed Lineage Leukemia (MLL) gene result in the fusion of the N-terminal portion of MLL to one of its translocation partner genes, giving rise to chimeric MLL fusion proteins. Such MLL-rearrangements occur in both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), and often specify highly unfavorable and difficult to treat malignancies. The propensity of several MLL fusion proteins to induce AML in hematopoietic stem cells (HSCs) has convincingly been recapitulated in various mouse models. In contrast, however, modeling MLL fusion driven ALL has proven to be very difficult. Various attempts to genuinely mimic human MLL-rearranged ALL in mice by enforced expression of MLL fusion genes mainly resulted in the development of lymphomas or leukemias displaying phenotypes that significantly deviate from the highly immature pro-b cell phenotype characteristically found in humans. Moreover, in some recent studies the introduction of MLL fusion expression in cord blood derived HSCs was not even sufficient to initiate any form of leukemia at all. Collectively, these studies form the basis of an ongoing debate questioning whether we have been targeting the correct hematopoietic stem/progenitor cell (HSPC), or whether other or additional factors are required to develop fullblown MLL-rearranged pro-b ALL. Meanwhile, the lack of a proper MLL fusion driven ALL leukemogenesis model is hampering our understanding of vital processes during transformation, which potentially conceal important insights into how to effectively treat this type of leukemia. Hence, we need to find the right strategy of mimicking MLL fusion driven leukemogenesis in mice. Now, it has been well documented that the MLL fusions in human patients arise during pregnancy, during a developmental stage at which hematopoiesis still largely takes place in the fetal liver. Therefore we believe that the cell of origin in which this type of leukemia arises should be a fetal liver HSC or early B-cell progenitor. To test this hypothesis, we are currently using fetal liver derived HSCs in which we induce enforced MLL-AF4 expression prior to injecting those cells in immunideficient NSG mice. Momentarily we have one mouse that had succumbed to leukemia, and a second mouse is also showing signs of leukemia but, to date, is still alive. The leukemia of the first mouse has been re-transplanted into secondary recipient mice. As soon as these mice also get leukemia, we will initiate experiments in which we will characterize the immunophenotype of the leukemic cells, detect whether the MLL-AF4 fusion protein is indeed present in these cells, and compare the (epi)genetics of these cells to that of primary MLL-AF4+ infant ALL patient samples. In the meantime I have been subjecting primary MLL-AF4+ infant ALL cells to next generation Exome sequencing in order to find possible cooperative genetic lesions that may contribute to the leukemogenesis process. In case we find such lesions, these will be co-expressed together with the MLL-AF4 fusion in fetal liver HSCs and again transplanted into mice. 35

36 NAAM: Wilco Smits Research analist Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam- Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Abstract Keywords: T-cell acute lymphoblastic leukemia, molecular cloning, mutation screening I m a research technician in the T-ALL research group of dr. Jules Meijerink. My primary area of expertise is the design and production of lentiviral gene-expression vectors. These vectors are utilized in a number of projects where cells are genetically modified to enforce expression of an oncogene. One example is our T-ALL Whole Genome Sequencing project where we found mutations that contribute to cancer. By introducing these mutated genes to cell lines we can learn more about their oncogenic function. I m involved in experiments that help to identify essential signaling pathways. This will allow us to develop and test targeted therapy. My daily activities include a variety of recombinant DNA techniques, virus production, cell culture, protein work (WB, IP) and PCR. Additionally, I support my colleagues with their in vivo experiments and contribute to the genetic characterization of patient material (Sequencing, MPLA) 36

37 NAAM: Ronald Stam Groepsleider Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, drug resistance, epigenetics, MLL fusion driven leukemogenesis, bone marrow microenvironment, CNS infiltration, cell-cell communication. Abstract: Acute lymphoblastic leukemia (ALL) in infants (i.e. children <1 year of age) is characterized by a high incidence of leukemia-specific chromosomal translocations of the Mixed Lineage Leukemia (MLL) gene, which occur in ~80% of the cases. In turn, MLLrearranged infant ALL represents one of the most aggressive and difficult to treat types of childhood leukemia. Consequently, the event free survival rates for these very young patients is currently at best 30-40%. With his enthusiastic research group, Ronald aims to: 1. Understand the biology and (epi)genetics underlying leukemogenic transformation and pre-leukemic stages of the malignancy progressing towards full-blown overt leukemia, 2. Unravel the molecular mechanisms underlying drug resistance and therapy failure, and develop therapeutic strategies to circumvent adverse drug responses, 3. Identify novel therapeutic targets and develop more adequate pre-clinical treatment rationales, 4. Study the role of the bone marrow microenvironment in leukemia maintenance, progression and relapse, 5. Gain insights into the aggressive and invasive nature of this type of leukemia using central nervous system infiltration as a model, 6. Develop and optimize in vitro and in vivo model systems of this aggressive malignancy, and 7. Elucidate the influence of cellto-cell communication with a focus on extracellular vesicle exchange. 37

38 NAAM: Lieneke Steeghs PhD student Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Abstract: Key-words: Pathobiology ALL, oncogenomics, BCR-ABL1-like ALL, microenvironment, ALL xenografts, targeted drugs. Although the survival rates in acute lymphoblastic leukemia (ALL) have improved during the last decades, certain cytogenetic subtypes are still associated with a poor prognosis. In our studies, it is aimed to explore the biology of childhood B-cell precursor ALL (BCP-ALL) and the role of the bone marrow microenvironment in leukemia progression. The BCR-ABL1-like subgroup (BAL) is a poor genetic subtype. Currently, no targeted treatment for this patient group is available yet. Gene expression profiling and proteome profiling of BCP-ALL cells was used to identify genes characteristic for BAL leukemic cells. By lentiviral-assisted interfering with expression levels, the role of these genes in leukemia is being analyzed. Additionally, a gene mutation screen of JAK2 in BCP-ALL patients was performed. Patients carrying JAK2 mutations and JAK2 fusion genes were identified. These aberrations locate in the pseudokinase domain and have been described to result in constitutive JAK2 activation. We are investigating which JAK2 inhibitor has the highest specificity and whether JAK2 mutated cells are as sensitive to these inhibitors as JAK2- fusion cells. Mesenchymal stromal cells (MSCs) are involved in the development and differentiation of normal hematopoietic cells and support the survival of leukemic cells. We consistently observe that ALL cells cultured on top of MSCs are more viable and less apoptotic than ALL cells cultured as monoculture. Moreover, ALL cells in co-culture with MSCs are more resistant to chemotherapeutic drugs including prednisolone and L-asparaginase. We observed that MSCs of leukemic patients taken at the time of diagnosis (when MSCs are still in close contact with ALL cells) have different intrinsic protein profiles than MSCs obtained at the time of remission or from non-leukemic control patients, such as the tyrosine kinase receptor EphA2. Silencing of EphA2 (with shrna) did not affect the viability of MSCs, nor did these conditions interfere with the increased viability seen when ALL cells are cultured on top of MSCs. This suggests that other factors may affect the survival of ALL cells in cocultures. Several other candidate genes were shown to be differentially expressed and functional studies are currently being performed. 38

39 NAAM: Dr. Blanca G.P.H. Scheijen Groepsleider Naam Centrum: Radboud umc Naam Research groep: Laboratory of Pediatric Oncology Research interesses/expertises: Leukemia, Hematopoiesis, Knockout and transgenic mouse models, Oncogenic tyrosine kinases, Transcriptional and epigenetic networks My research projects involve the following topics 1. Define novel strategies for targeting oncogenic tyrosine kinases in leukemia through molecular characterization of downstream pathways Delineate the function of mutant FLT3, JAK kinases and BCR-ABL1 in lymphoid and myeloid malignancies in modulating signaling and transcriptional networks 2. The role of Ikaros (IKZF1) in leukemia outgrowth and therapy resistance Define the function of tumor suppressor IKZF1 in leukemia development through identification of critical downstream pathways and cooperating genetic aberrations. Unravel the molecular mechanisms by which IKZF1 mediates differential chemotherapy responses Investigate functional interaction between IKZF1 and p53 3. Modeling and targeted therapies of aberrant RUNX1 function in leukemia Elucidate the underlying mechanism of leukemia development by RUNX1 overexpression and ETV6-RUNX1 fusion protein in BCP-ALL 4. The function of tumor suppressor BTG1 in normal and malignant hematopoiesis Uncover the role of BTG1 in normal lymphoid differentiation and in leukemia development through identification of downstream genetic pathways and collaborating gene lesions. 39

40 NAAM: Cesca van de Ven Postdoc Naam Centrum: Erasmus MC-Sophia Children s Hospital, Dept. of Pediatric Oncology Naam Research groep: B-cell precursor-all, PI: Prof.dr. Monique L. den Boer Key-words: Pathobiology ALL, BCR-ABL1 and BCR-ABL1 like ALL, targeted drugs,microenvironment, ALL xenografts, humanized scaffold models. Inter- and intrapatient heterogeneity plays a significant role in the response of patients to chemotherapeutic drugs. We are addressing this heterogeneity, how it may influence the behavior of ALL cells and in which way we can use this heterogeneity to discover new drugable targets using both in vitro and in vivo models. We have found that BCR-ABL1 positive ALL cases differ in phosphorylation levels of proteins and are currently investigating whether other proteins, beside BCR-ABL1 fusion protein, may serve as alternative targets for treatment. The microenvironment of the leukemia may also plays a substantial role in treatment response, since it can be transformed to favor leukemic cell support and provide a safe haven for ALL cells to escape chemotherapy. Chemokine and cytokine profiles of mesenchymal stromal cells differ between patients. We are currently investigating by mass spectrometry which other proteins may be differentially produced by mesenchymal cells at the time of leukemia. Functional studies address how effective these proteins transform the microenvironment to a pro-leukemic state, since this may preclude a target for treatment. Studies on the pathobiology of ALL and in vitro drug studies point to new targets for treatment. However, in the progress from bench to bedside, in vivo testing of a drug in mice is an invaluable step. To this aim, we have established xenografts of primary leukemic cells with different genomic lesions/genetic subtypes into immune-deficient mice. We are currently performing a proof-of-concept study of Ibrutinib for the treatment of TCF3-PBX1 positive ALL as well as other leukemias with activated prebcr pahway. These leukemias are characterized by a high expression of Bruton s Tyrosine kinase (BTK) and downstream effectors and these leukemic cells can be preferentially killed by Ibrutinib in vitro. In parallel to ALL xenograft studies, together with the group of A. Martens (UMCU/VUMC), we have optimized a scaffold mouse model which enables us to manipulate the human leukemic niche in vivo using mesenchymal cells of pediatric patients. These models are used to interfere with the homing and migration of leukemic cells by manipulating leukemic or mesenchymal cells (e.g. by silencing of genes) and to study the effect of potential drugs that interfere with the leukemia-microenvironment. 40

41 NAAM: Mirjam van de Velde Promovendus studie Vincristine-Induced Neuropathy in Children with Acute lymphoblastic leukemia Naam Centrum: VUmc Naam Research groep:all Abstract Rationale: Vincristine (VCR) is a commonly used chemotherapeutic drug in the treatment of pediatric acute lymphoblastic leukemia (ALL). The main dose-limiting side effect of VCR is peripheral neuropathy (PNP). The quality of life of children who suffer from VCR-induced PNP is severely affected. There is a lack of information regarding the optimal therapeutic dosing and method of administration of VCR for children with cancer. High peak plasma concentrations seem to be correlated with PNP. The study is set up as a prospective, multi-center, open-label, randomized controlled trial with a duration of 42 months. Objective: This study aims to investigate whether the administration of VCR in children aged 2-18 years newly diagnosed with ALL by one-hour infusions, resulting in lower peak plasma concentrations, leads to less PNP compared to bolus injections. In addition, quality of life, (non-)medical costs, and treatment efficacy associated with both administration methods will be evaluated. Moreover, it will be investigated whether other factors, such as pharmacokinetics and genetic susceptibility to drug-induced side-effects, also influence the degree of PNP. Intervention: Patients will be randomized into two groups. Patients in group A (the bolus group) will receive all VCR administrations during their two-year treatment period by bolus injections. Patients in group B (the infusion group) will receive all VCR administrations by one-hour infusions. Hopefully this results in less PNP and improved quality of life, for all future childhood ALL patients, and other patients being treated with VCR. 41

42 NAAM: E.M. Vroegindeweij Postdoc Naam Centrum: Department of Pediatric Oncology/Hematology, Erasmus MC Rotterdam-Sophia Children s Hospital, Rotterdam, the Netherlands Naam Research groep: T cell-acute Lymphoblastic Leukemia Research Group (Principal Investigator: Dr. J.P.P. Meijerink) Keywords: T-cells, T-cell acute lymphoblastic leukemia (T-ALL), monocyte enhancement factor 2C (MEF2C), oncogenes, cancer Abstract I am a postdoc in the T-ALL research group of Jules Meijerink. I have a background in thymus biology and normal T-cell development. My current research focuses on the biology of the oncogene MEF2C. The transcription factor monocyte enhancement factor 2C (MEF2C) plays an important role in the development of common lymphoid progenitors and B cells. In early T-cell development, MEF2C is still expressed but becomes downregulated at a late early thymocyte progenitor (ETP) stage that is considered as the T-cell commitment checkpoint. We previously reported that MEF2C potentially acts as an oncogene in a subset of T-cell acute lymphoblastic leukemia (T-ALL) that is correlated with early T-cell development, i.e ETP-ALL. Here MEF2C may collaborate with other co-factors in creating a pathogenic condition that promotes the acquisition of additional mutations and ETP-ALL. We are currently investigating the characteristics of MEF2C and its binding partners in a T-ALL invitro model system. So far, we found that MEF2C collaborates with LIM domain only 2 (LMO2) and Lyl-1 that can bind the DNA as a complex. By screening different mutants of the proteins we identified the regions that are required to form the complex. At present, we are investigating potential target genes that become deregulated by this MEF2C transcriptional complex. 42

43 NAAM: Priscilla Wander Promovendus Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, NF-kB, glucocorticoid resistance. Abstract: Acute Lymphoblastic Leukemia (ALL) in infants is characterized by a high incidence of MLL-rearrangements. Infants (<1 year of age) carrying such chromosomal translocations of the MLL gene are burdened with a poor prognosis, mainly due to cellular resistance to chemotherapeutics, in particular to glucocorticoids. An important glucocorticoid is prednisone, which is a spearhead drug in the treatment of ALL. Therefore, overcoming resistance to this drug would be an important step towards an improved prognosis. Hence, we performed an in vitro drug screening of several FDA approved drug libraries to identify agents that sensitize ALL cells carrying MLL-rearrangements to prednisone. We found a possible prednisone sensitizing small molecule inhibitor, which is currently being validated on diverse MLL-rearranged cell lines and primary material. In addition, the known inhibitory mechanism exerted by this drug, in combination with recently published data by others indicate that the nuclear factor kappa-light-chain-enhancer of B-cells (NF-kB) likely plays a pivotal role in MLL-rearranged ALL leukemogenesis and drug resistance, which represents the central theme of my research. 43

44 NAAM: Merel Willekes Research technician Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, MLL-AF4 driven leukemogenesis, fetal liver HSCs, in vivo mouse model. Abstract: As a research technician I support the work of our PhD-students and post-docs in the MLLrearranged infant acute lymphoblastic leukemia research group. In particular I am involved in our research on MLL-AF4 driven leukemogenesis in immunodeficient mice. Although MLLrearranged infant ALL represents a highly aggressive type of leukemia, decades of research worldwide have shown that the leukemogenesis of MLL-AF4+ infant ALL is very difficult to model in mice. In fact, no representative mouse model currently exists that accurately recapitulate the malignancy as seen in humans. In our opinion this is due to the fact that in all attempts so far researchers have used cord-blood or bone marrow derived hematopoietic stem cells (HSCs) as the target cell in which enforced expression of MLL-AF4 was induced, upon which these presumed pre-leukemic cells are transplanted into mice. Yet, it has been well documented that the MLL fusions in human patients arise during pregnancy, during a developmental stage at which hematopoiesis still largely takes place in the fetal liver. Therefore we believe that the cell of origin in which this type of leukemia arises should be a fetal liver HSC or early B-cell progenitor. To test this hypothesis, we are currently using fetal liver derived HSCs in which we induce enforced MLL-AF4 expression prior to injecting those cells in immunideficient NSG mice. Momentarily we have one mouse that had succumbed to leukemia, and a second mouse is also showing signs of leukemia but, to date, is still alive. The leukemia of the first mouse has been re-transplanted into secondary recipient mice. As soon as these mice also get leukemia, we will initiate experiments in which we will characterize the immunophenotype of the leukemic cells, detect whether the MLL-AF4 fusion protein is indeed present in these cells, and compare the (epi)genetics of these cells to that of primary MLL-AF4+ infant ALL patient samples. 44

45 NAAM: Anna Wojtuszkiewicz Promovendus Naam Centrum: VUmc Naam Research groep: Pediatric Oncology/Hematology Abstract: Alternative splicing in acute leukemia: the relevance for drug resistance and treatment Pre-mRNA splicing has recently come to attention in hematological malignancies as a novel prognostic tool and contributor to pathogenesis as well as drug resistance. In this study, we explored the relevance of alternative pre-mrna splicing in drug resistance of leukemia. Firstly, we examined aberrant FPGS splicing as a denominator of MTX resistance. Comprehensive screening of the FPGS gene showed many different splice variants and the relation with impaired FPGS activity as determined by computational biology and FPGS activity assays. In particular, retention of part of intron 8 (8PR) was often detected and its levels were associated with biological markers of MTX activity as well as long-term survival in ALL patients with deficient MTX polyglutamylation. The presence of 8PR was also associated with resistance to other drugs, which may reflect a broader deficiency in splicing regulation. The relevance of splicing for overall drug resistance is also underscored by our finding that pre-mrna splicing is a major functional protein cluster upregulated in the secretome as well as exosomes secreted by apoptosis-resistant primary AML cells. This likely enables transfer of drug resistance to neighboring apoptosis-sensitive cells. Finally, we evaluated whether the pre-mrna splicing is a suitable target for therapy in pediatric leukemia using a novel spliceosome inhibitor- the SF3B1 inhibitor meayamycin B (MAMB). Our data on cell viability and splicing modulation of in vitro spliceosome inhibition by MAMB are promising and warrant further investigation in the applicability of interference in splicing as novel treatment strategy. 45

46 NAAM: Jiangyan Yu Promovendus Naam Centrum:Radboudumc, Nijmegen Naam Research groep:cancer Genomics (PI Roland Kuiper) Abstract: B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is one of the most common cancers in children. The relapse incidence varies between 15% and 25%, dependent on the treatment protocol. Relapses in ALL are thought to result from the outgrowth of therapyresistant residual leukemia cells and recent studies have shown a complex, dynamic architecture of clonal diversity in ALL. However, the clinical importance for subclonal genetic aberrations for relapse risk is still poorly defined. I am investigating the multiclonal architecture of ALL in relation to therapy resistance and the origin of relapse using comprehensive genetic characterization of diagnosis-relapse pairs and backtracking of relapse-specific aberrations in diagnosis samples in order to identify relapse-initiating clones. We have demonstrated that cells harboring mutations in the Ras pathway genes (KRAS, NRAS, PTPN11, FLT3, BRAF, CBL) are present in 30% of the BCP-ALL relapses, and can be backtracked in (sub)clones at diagnosis in 79% of these cases. Currently, I am studying the clinical relevance of subclonal aberrations in Ras pathway genes, as well as other recently identified prognostic markers, at time of diagnosis using ultra-deep targeted next generation sequencing. To increase the sensitivity of this approach and correct for amplification biases, we use random tagging based single molecule Molecular Inversion probe (smmip) technology to reliably detect mutations >0.1% of the cells. We expect that these studies will yield new valuable insights into the properties of relapse-initiating cells in leukemia, and will provide novel strategies for future routine diagnostics and relapse prediction at diagnosis. 46

47 LYMPHOMAS 47

48 NAAM: Friederike Meyer-Wentrup, MD, PhD, kinderoncoloog X Groepsleider Naam Centrum: Prinses Maxima Centrum Naam Research groep: Boes/ Meyer-Wentrup Abstract Our research focusses on the host-tumor interaction. We are interested in targeting tumor immune evasion mechanisms to treat pediatric cancer. It is our aim to understand immune evasion in solid tumors and lymphomas using complementary translational approaches. We stay as close to the patient as possible while using all scientific methods and techniques necessary to answer fundamental immunological questions, applying our combined expertise as clinician-scientist (FMW) and fundamental lab-researcher (MB). In this line, we have recently discovered that neuroblastoma cells express the immune inhibitory molecule CD274 and that inflammatory triggers such as TLR3 activation and IFNγ stimulation induce CD274 and MHC class I upregulation leading to T-cell activation. We are in the process of generating murine monoclonal anti-cd274 antibodies to study CD274 biology and expression in pediatric solid tumors and lymphomas. In Hodgkin lymphoma we aim at understanding the lymphoma microenvironment and the biology of Reed-Sternberg tumor cells. In addition, we wish to identify Hodgkin lymphoma biomarkers for outcome prediction and risk stratification. We propose that understanding the host-tumor interaction will pave the way for developing novel immune therapies to treat pediatric cancer. 48

49 NAAM: R.A.J. (Rutger Jan) Nievelstein Klinisch-projectleider Naam Centrum: UMC Utrecht/Wilhelmina Kinderziekenhuis Naam Research groep: Advanced imaging techniques for staging and follow up of malignant lymphoma Abstract Malignant lymphomas are a heterogeneous group of malignancies with a highly variable biology and prognosis. Improved understanding of the tumor biology enables selecting the most likely effective therapy, and will allow personalized monitoring of treatment response in each patient and provide the opportunity to switch from treatment strategy in case of a non-response. Early selection of an effective treatment strategy increases survival rate, and early stop of an ineffective therapy will prevent unnecessary sideeffects. It is therefore necessary to develop non-invasive imaging biomarkers that can be used to guide and optimize anticancer therapies in malignant lymphomas, from the moment of diagnosis until the completion of the optimal treatment in each patient. This project will focus on a combination of advanced, but widely implementable positron emission tomography (PET) and magnetic resonance imaging (MRI) biomarkers for staging and early response assessment of malignant lymphomas. 49

50 NAAM: Eline Zijtregtop Promovendus Naam Centrum: Erasmus MC-Sophia Naam Research groep: EuroNet-PHL-C2 Abstract Aim: This project aims to identify biomarkers and novel therapeutic targets for pediatric Hodgkin lymphoma. Background: Successful treatment of Hodgkin lymphoma comes at the cost of significant long-term toxicity. Strikingly, therapeutic regimens have not changed much during the past 20 years partly due to a lack of biomarkers or targeted therapy. Hodgkin lymphoma is a peculiar malignancy, because malignant cells are greatly outnumbered by reactive cells in the tumor microenvironment. This environment is of major importance for the proliferation and survival of HRS cells. While the impact of the microenvironment on the specific pathology of HL becomes increasingly clear, the exact role of the microenvironment in pediatric Hodgkin lymphoma is not known. Besides, genetic analysis of malignant Hodgkin cells has been hampered by their scarcity and has largely been done with laser-dissected samples. Plan of investigation: We therefore plan to take a triple approach: we want to analyze FACS-sorted malignant Hodgkin and Reed-Sternberg cells by whole exome sequencing and gene expression arrays. This will give detailed information on the genetic alterations in malignant Hodgkin cells and the reactive immune phenotype of the lymphoma microenvironment. We propose that this knowledge will translate into better therapies for pediatric Hodgkin lymphoma patients. At the same time we want take a closer look at the tumor microenvironment by immunohistochemistry and gene expression profiling of microenvironment-derived T-cells. This will allow us to place genetic findings in malignant lymphoma cells in the context of the lymphoma microenvironment. Finally, we want to investigate new serum biomarkers and directly compare to FDG-PET imaging to explore it s value as disease response markers. This will give us profound insight into the Hodgkin lymphoma microenvironment including expression of immune inhibitory markers such as PD-1 and PD-L1 that can be targeted by antibody therapy. 50

51 MYELOID MALIGNANCIES 51

52 NAAM: Marije Bartels Kinderhematoloog/onderzoeker Naam Centrum: UMC Utrecht Naam Research groep: Epigenomics of myeloid disorders (collaboration with dr.m. Creyghton, Hubrecht Institute) Abstract: In contrast to DNA hypermethylation profiles, the role of specific histone modifications in AML and MDS biology is less well defined, while it has been demonstrated that loss or gain of distinct histone modifications are early hallmarks of cancer development. In addition, it has recently been demonstrated that altered activity of epigenetic regulators plays a role in the clonal evolution and therapy resistance of pre-leukemic hematopoietic stem cells Based on these recent studies in MDS and AML in adults, it is reasonable to assume that epigenetic regulators also play an important role in pediatric myeloid disorders and the development of chemotherapy resistance. Through a multifaceted, unbiased, high throughput approach, utilizing epigenetic profiling, high content epigenetic compound screening, and CRISPR-CAS9 technology, in combination with mechanistic studies in normal and patient-derived CD34+ cells, we will investigate the epigenomic landscape of myeloid disorders in childhood. This will lead to an improved understanding of pediatric MDS and AML biology, and subsequently aims to uncover novel therapeutic targets, reducing chemotherapy resistance, and thereby resulting in improved therapeutic efficacy. 52

53 NAAM: Maarten Fornerod Groepsleider Naam Centrum: Erasmus MC - Sophia Children's Hospital Naam Research groep: Myeloid malignancies, MDS and Down Syndrome Leukemias (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: Myeloid malignancies, MDS and Down Syndrome Leukemias 53

54 NAAM: Noorjahan Jagalur Basheer Postdoc Naam Centrum: Erasmus MC - Sophia Children's Hospital Naam Research groep: Myeloid malignancies, MDS and Down Syndrome Leukemias (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, mouse models for fusion oncogenes, Genome wide mapping, Epigenetic compounds, novel targeted therapy Abstract: Recently our group has identified two novel translocations among the cytogenetically normal pediatric AML patients namely, NUP98-NSD1 and NUP98-KDM5A which are largely chemotherapy resistant. Both subgroups result in maturation arrest of the cells and have an extremely poor outcome with overall survival rates of 31% for NUP98-NSD1 and 22% for NUP98-KDM5A patients. Furthermore, current treatment-related mortality rates prohibit further intensification of therapy. NUP98 is found to be frequently translocated in hematopoietic malignancies. While NSD1 is a lysine methyltransferase, KDM5A is a lysine demethylase, which are able to mark/remove the epigenetic mark on the chromatin. To systematically search entry points in developing effective targeted therapies for this particular AML subtype, first we need to know how these two fusion proteins generate aberrant gene expressions programs. My project aims to create both cell culture and mouse models of these fusion oncogenes. In addition, we are working towards generating bone marrow transplantation mouse models with NUP98-NSD1 or NUP98-KDM5A translocation. We will use these models to identify the oncogenic pathways and collaborative events resulting in leukemia. The knowledge could lead us to identify novel therapeutic targets. Furthermore, we will use these in vitro and in vivo models to do epigenetic drug screening that can selectively kill cells bearing specific NUP98 translocations. 54

55 NAAM: Prof.dr. G.J.L. Kaspers Centrumhoofd Naam Centrum: VU medisch centrum Naam Research groep: VUmc kinderoncologisch centrum Abstract: VUmc has an extensive pediatric oncology research program, embedded in the research of VUmc Cancer Center Amsterdam. It mainly is translational and consists of laboratory research, clinicalexperimentel studies, and quality of life and late effects research. In the clinical and laboratory research we focus on leukemia, retinoblastoma and brain tumors. 55

56 NAAM: Kim Klein Promovendus Naam Centrum: VUmc Naam Research groep: CCA Abstract: Although survival rates have increased substantially over the past years, the outcome of pediatric AML remains unsatisfactory with an overall survival around 70%. One of the main problems involves the relatively high relapse rate of 30-40% after primary treatment. To contribute to better survival rates and to improve patient-tailored and targeted therapy more prognostic and drugable factors need to be identified. Because of the extensiveness of this goal, this project will be restricted to several components (all concerning pediatric patients): Cytogenetics: Additional cytogenetic aberrations, N-RAS/K-RAS mutations and ckit mutations in t(8;21)-positive AML Evaluation of the role of TP53 mutations in pediatric AML The role of FAB type M4 with eosinophilia in relation to inv(16) Relevance of cytogenetic shifts in relapsed AML, compared to initial AML Treatment response: In vitro effects of glucocorticoids on AML blast cells Study of early blast clearance in peripheral blood in childhood AML, as a new and simple prognostic tool for follow-up Prospective analysis of the prognostic significance of routine bone marrow examination and peripheral blood monitoring 56

57 NAAM: Patty Kok Research analist Naam Centrum: Erasmus MC - Sophia Children's Hospital Naam Research groep: Myeloid malignancies, MDS and Down Syndrome Leukemias (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, mouse models for fusion oncogenes, Genome wide mapping, Epigenetic compounds, novel targeted therapy Abstract: I have been a research technician in the Acute myeloid Leukemia (AML) group from past one year. During this time I have had a supportive role in the projects of PhD students and postdocs and have been using many different techniques, like qpcr, cloning, transfection, transduction, generation of stable cell lines-etc. Mainly I am focused on one specific project, working together with one of our postdocs. We are interested in the better understanding of NUP98-NSD1 translocation in pediatric leukemia. This translocation is observed in 16% of pediatric cytogenetically normal-aml cases and has poor outcome with an overall survival rate of 31%. We are generating a mouse model with the NUP98-NSD1 translocation. This will give us better understanding of leukemic pathways involved in this subtype of pediatric AML and it will help us to design better therapeutic strategies. 57

58 NAAM: Nicole S.D. Larmonie Postdoc Naam Centrum: Erasmus MC - Sophia Children's Hospital Naam Research groep: Myeloid malignancies, MDS and Down Syndrome Leukemias (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, DNA methylation, epigenetics, nuclear organization Abstract: Much progress has been made towards improving of overall survival in pediatric acute myeloid leukemia (AML). However, despite intensive and highly toxic conventional chemotherapy regimens, survival rates have plateaued at 60-70% and after achieving complete remission about 30% of patients still relapse. Thus AML remains a life-threatening malignancy in children. The high mortality, morbidity and elevated risk for relapse stresses the need for better therapeutics for treatment of pediatric AML. AML leukemogenesis is driven by collaborative genetic abnormalities that induce hematopoietic maturation arrest and cell proliferation. These genetic abnormalities are of diagnostic, and prognostic value. Particular AML-associated maturation inhibiting aberrations are known to target chromatin regulators, thus directly influencing the transcriptional program of leukemic cells through the de regulation of epigenetic processes. Therapies targeting epigenetic processes, e.g. hypomethylation-inducing agents, are therefore becoming an attractive therapeutic strategy in AML. However, to target pediatric AML-specific targets involved in deregulation of epigenetic processes, a comprehensive understanding of involved underlying epigenetic mechanisms in pediatric AML tumorigenesis and resistance are required. This project is aimed at identifying differences in methylation patterns in pediatric AML subgroups based on genome-wide CpG-island DNA methylation profiling analysis. This, to provide the rational for treatment of pediatric AML patients with demethylating-agents and to identify novel deregulated genes in pediatric AML. 58

59 NAAM: Hasan Mahmud post Doc Naam Centrum: University Medical Center, Groningen Naam Research groep: Pediatric Oncology/ Hematology Kinomic profiling of pediatric acute myeloid leukemia for detailed cellular insights Hasan Mahmud, 1 Pariya Behrouzi, 2 Arja ter Elst, 1 Frank JG Scherpen, 1 Kim R Kampen, 1 Valérie de Haas, 3 Victor Guryev, 4 Maikel M Peppelenbosch, 5 Frank Johannes, 2 Steven M Kornblau, 6 *Eveline SJM de Bont. 1 1 Department of Pediatric Oncology/Hematology, Beatrix Children s Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; 2 Groningen Bioinformatics Center, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, The Netherlands; 3 Dutch Childhood Oncology Group, The Hague, The Netherlands; 4 Laboratory of Genome Structure and Ageing, European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; 5 Department of Gastroenterology and Hepatology, Erasmus Medical Center, Rotterdam, The Netherlands; 6 Department of Leukemia & Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States. Abstract: Acute myeloid leukemia (AML) remains a life threatening malignancy in children and the precise etiology remains unclear. Therefore, it is essential to evaluate the activation of the components of cellular signaling pathways to understand AML signaling and to design the most successful approach for combinational therapies and new kinase inhibitors. In this study, we used a high-throughput PepChip TM Kinomics microarray system containing 976 different kinase substrates and assayed primary leukemic samples of 96 AML patients to produce an exceptionally detailed map of kinome enzymatic activities towards predefined peptide substrates. The generated profiles provide a comprehensive insight in signaling pathways active in AML patients. Unsupervised hierarchical cluster analysis separates the AML blast profiles based on 192 peptide activities into two clusters. Cumulative incidence of relapse (CIR) was significantly higher in the patients of cluster-2. Peptide activity patterns were independent of patient characteristics. To understand signaling dynamics activated in two clusters, we assessed pathway analysis of active peptides of two clusters. GeneGO pathways analysis revealed that activation of immune response via complement 5 receptor, AKT signaling and G-protein mediated p38-jnk pathways are heterogeneously active in both clusters. Peptides involve in cell proliferation and migration are highly activated in cluster-2. DNA repair mechanism was also highly activated in cluster-2 patients. On the other hand, cell cycle arrest and DNA damage response signals were highly activated in cluster-1. In addition, with Gaussian network modeling, a total of 540 peptides (55%) showed at least one peptide-peptide association without a prior assumptions whereas 74 peptides (7.5%) had >39 nodes suggesting to be potential interesting signaling hubs. Among these 74 peptides, 10 peptides were identified in cluster-1 and 50 peptides were in cluster-2. Thus, this total analysis defined active peptides and signaling hubs that are correlated to low incidence for relapse and to high incidence for relapse. In conclusion, our study demonstrates the feasibility of peptide activity profiling to identify two active signaling network clusters in pediatric AML correlated to CIR. 59

60 NAAM: Sanne Noort Promovendus Naam Centrum: ErasmusMC Sophia Children s Hospital Naam Research groep: Myeloid malignancies and Down Syndrome (PIs: CM Zwaan, MM van den Heuvel-Eibrink, M Fornerod) Key words: AML, mutation discovery, next generation sequencing, risk stratification Abstract: Despite major progress in improving treatment, acute myeloid leukemia (AML) remains a life threatening malignancy in children. With current treatment protocols a plateau in survival has been reached. The overall survival (OS) is 60-70% and the event free survival (EFS) is ~50%. Further chemotherapy intensification is unfeasible as ~5-10% of patients die due to treatment-related toxicity. Further improvements should come either form targeted therapy or from improved risk group stratification, which requires eludicating the oncogenetic drivers in pediatric AML. However, at diagnosis ~25% of patients present without known driving genetic aberration, either by karyotype or molecular diagnosis. Therefore the aim of this project is define the underlying driving oncogenic aberrations in a group of pediatric AML patients for which mutations causative for differentiation arrest and/or proliferation advantage are unknown. Another aim is to improve risk-group stratification and start the process of developing targeted treatment options for these patients. To reach the aims of this project, RNAsequencing and exome capture deep sequencing will be performed to find new driving oncogenic aberrations. 60

61 NAAM: JULIA OBENAUER x Promovendus Naam Centrum: Erasmus MC, Rotterdam & Prinses Maxima Centrum, Utrecht Naam Research groep: Prof. I. Touw, Dr. Marry van den Heuvel-Eibrink, P.Sonneveld Abstract The study of the clonal composition of cancers and hematological malignancies contributed to the understanding how the malignancies arise, and how resistance and relapse might occur. We aim to study two hematological diseases in further detail: juvenile myelomonocytic leukemia (JMML) and severe congenital neutropenia (SCN). JMML is a myeloproliferative neoplasm induced by RAS-pathway activating aberrations. Despite identification of recurrently affected genes (PTPN11, NRAS, KRAS, c-cbl), the genetic background of the disease is unaccounted for 15-20% of the JMML patients. We aim to further characterize the malignancy, and specifically the patients with yet unknown alterations, by using next generation DNA sequencing techniques. SCN is a bone marrow failure syndrome characterized by a severe reduction of blood neutrophil levels in the patients, due to aberrations in genes associated with neutrophil development such as ELANE or HAX1. Patients receive treatment in form of CSF3 administration. Around 20% of the patients develop acute myeloid leukemia (AML), which is incurable to date. At the course of this project, we identified a high co-occurrence of CSF3R and RUNX1 aberrations in leukemic progression from the disease. Currently, we are studying the synergistic effect of aberrations in these two genes in vitro in colony forming assays and liquid cultures, and aim to understand the molecular background by next generation sequencing. In addition, we aim to elucidate how CSF3 treatment might contribute to the malignant phenotype. 61

62 NAAM: Askar Obulkasim Postdoc Naam Centrum: Erasmus MC - Sophia Children's Hospital Naam Research groep: Myeloid malignancies, MDS and Down Syndrome Leukemias (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, data integration, classification, data mining, next generation sequencing Abstract In recent years the treatment of pediatric AML has reached a plateau, and further intensification of current chemotherapy protocols is not possible due to toxicity. Therefore, novel therapies that more efficiently target the disease are required to further improve outcome of pediatric AML. We performed several profiling studies in a clinically well-described pediatric AML cohort on which large amounts of omics data were gathered. The general hope is that highthroughput omics data might further our understanding of patient- level variability in clinical outcomes by utilizing subtly yet important variabilities at the molecular level. Given that complex diseases, such as pediatric AML, arise as a result of orchestrated genomic, epigenomic, transcriptomic, and proteomic alterations, integration of multiple heterogeneous omics data have great potential to aid in novel molecular subtypes discovery. In this project we aim to identify new pediatric AML subtypes via data integration. We try to develop a novel data integration platform in which different types of omics data are fused. The goal is then to unravel pediatric AML subtypes with distinct clinical outcomes using this integration scheme. Our integration scheme (a) uses hard-earned fundamental biological relationships between data types and well-curated biological networks. Consequently, the identified subtypes are easy to interpret, and may assist in better understanding of the molecular taxonomy of pediatric AML; (b) is flexible enough to accommodate any type of omics data; (c) lifts the restriction placed on the number of data types to use at the same time; (d) utilizes the relative rather than absolute expression value of genes. Hence it is robust against variety sources of variations that haunted omics data. 62

63 NAAM: Jasmijn de Rooij Promovendus Naam Centrum: Erasmus MC-Sophia Children's Hospital Naam Research groep: Myeloid malignancies and Down Syndrome (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, subgroup discovery, AMKL, HOX gene regulation Abstract: The overall survival of children with acute myeloid leukemia (AML) has increased tremendously over the past decade. However, at present a plateau in survival has been reached with the available intensive chemotherapy regimens. Treatment intensification is not feasible due to high rates of treatment-related morbidity and mortality. Therefore novel therapeutic approaches are necessary, preferentially by using new drugs directing at specific molecular aberrations in the leukemic cells. It is known that HOX genes are frequently deregulated in leukemias, what appears to be a down-stream event of various primary oncogenetic hits. Aberrant HOX upregulation can result from translocations we recently found in pediatric AML like NUP98/NSD1 or NUP98/KDM5A. These oncogenetic events might serve as novel therapeutic target, as was recently shown for MLLtranslocations in AML with aberrant HOXA expression, by inhibiting DOT1L, which is recruited by the MLL-translocation complex. Aims of this project are to identify the driving underlying genetic aberrations of both HOX-activated and non-hox-activated pediatric AML cases without known genetic aberration, and provide insight in the HOX-activating mechanisms in NUP98/KDM5A and NUP98/NSD1 translocated cases to understand the biology of HOX-activated pediatric AML, which might direct the development of novel drugable targets. 63

64 NAAM: Stephanie Smetsers X Promovendus Naam Centrum: Wilhelmina Kinderziekenhuis UMC Utrecht Abstract Fanconi anemia: course of disease in the Dutch patient cohort and early recognition of cancer. In 2007 the SKION Fanconi anemia (FA) treatment guidelines and patient registry were implemented. To date, 122 Dutch FA patients are known of whom 75 are currently alive. On average, 3 children with FA are born in the Netherlands each year. Since 1972, 60 Dutch FA patients were transplanted. Stem cell transplantation (SCT) results have improved markedly, especially since the introduction of a fludarabine-based conditioning regimen. Life expectancy has improved and, consequently, more patients are confronted with other FA problems, such as oral squamous cell carcinoma (OSCC). Treatment possibilities for OSCC are limited since FA patients are hypersensitive to radiotherapy and chemotherapy. Frequent screening is therefore essential to discover (pre)cancer at an early stage. We analysed a non-invasive screening method, using brushed oral cells for loss of heterozygosity (LOH) analysis. LOH was present in 14 of 141 (9.9%) FA patients. LOH was significantly associated with OSCC. Measurement of LOH in brushed oral cells has a promising outlook in FA patients. However, assays need to be adapted for transplanted patients, since donor DNA in brushed mucosa disturbed LOH analysis. A survey, conducted in collaboration with the Dutch FA patient organisation to evaluate the current healthcare for FA in the Netherlands, shows that 45% of the patients receive suboptimal care despite the availability of FA treatment guidelines. In addition, the transition process from paediatric to adult healthcare proves to be difficult. From the patient's perspective, improvement of healthcare can be achieved by creating a multidisciplinary FA-team for children as well as adults. 64

65 NAAM: Pauline Schneider Research Technician Naam Centrum: Erasmus MC Sophia Kinderziekenhuis. Naam Research groep: MLL-herschikte acute lymfatische leukemie bij zuigelingen. Keywords: MLL-rearranged infant ALL, extracellular vesicles, bone marrow microenvironment, CNS infiltration. Abstract: As head of the technicians at the laboratory of pediatric oncology/hematology I supervise all the research technicians in terms of general lab tasks, securing the effectiveness and quality of our basic laboratory infrastructure. In addition I function as a research technician in the MLL-rearranged infant acute lymphoblastic leukemia research group, supporting the work of PhD-students and post-docs. Momentarily I am working on the cellto-cell communication between MLL-rearranged ALL cells and cells from the bone marrow microenvironment via extracellular vesicle exchange between these cells. Upon optimizing various methods of isolating these extracellular vesicles, I established that extracellular vesicles excreted by primary bone marrow mesenchymal cells are readily taken up by MLLrearranged ALL cells, and vice versa. Now I have turned to investigating the nature of the information that is exchanged between these cell types, by studying the contents of the vesicles (in terms of mrna, mirna and protein expression) and the effects on the receiving cells in terms of drug resistance, cell proliferation and survival, differentiation, and morphology. Recently I also initiated research on leukemic central nervous system (CNS) infiltration in MLL-rearranged infant ALL. As we have found CNS involvement at diagnosis or during the course of the treatment inevitably leads to early deaths, this phenomenon still represents an important obstacle in reaching favorable treatment results. In order to be able to study CNS infiltration I have optimized an in vitro blood-brain-barrier model, and together with the post-docs in our research group we obtained an in vivo mouse model for CNS infiltration. Results from both of these models showed that MLL-rearranged ALL cells are particularly capable of crossing the blood-brain-barrier and infiltration the brains of mice injected with specific MLL-rearranged ALL cell lines. My ongoing research is now focusing on the mechanisms by which these leukemia cells invade the CNS, in order to find therapeutic strategies to block this adverse process. 65

66 NAAM: Edwin Sonneveld Functie: molecular biologist Naam Centrum: SKION/DCOG Laboratory 66

67 NAAM: Lonneke Verboon Research Analist Naam Centrum: Erasmus MC-Sophia Children's Hospital Naam Research groep: Myeloid malignancies and Down Syndrome (PIs: CM Zwaan, MM van den Heuvel Eibrink, M Fornerod) Key words: AML, MLL-rearranged AML, mirnas, tumor cell analysis Abstract Each year, children are diagnosed with acute myeloid leukemia (AML) and ~40% will relapse during or after therapy. Twenty percentage of all pediatric AMLs have a mixed lineage leukemia (MLL) gene rearrangement. The clinical outcome for this subgroup is depending on the translocation partner in the MLL-rearrangement. The MLL gene regulates transcription by mediating chromatin modifications. A new class of small non-coding RNAs, micrornas (mirnas), was found that can regulate gene expression either via mrna cleavage or repression. MicroRNA expression is found to be deregulated in pediatric acute myeloid leukemia (AML), including MLL-rearranged AML. To date, few studies has been conducted to explore the contribution of mirnas is relapse development in pediatric AML. In this study, through microrna expression profiling of 6 paired initial diagnosis-relapse samples with MLL-rearrangements, we found 53 micrornas to be significantly differentially expressed in relapse samples (FDR <0.1). A total of 22 mirnas were validated with RTqPCR in paired initial diagnosis-relapse samples with MLL-rearrangements. MiRNAs of interest were overexpressed in MLL-rearranged AML cell lines and mrna and protein expression of predicted targets genes were determined by RT-qPCR and Western blot, respectively. Expression levels of predicted targets were also determined in available patient material. In addition, support is provided to other technicians, PhD-students, and Postdocs when necessary. General task, such as isolation leukemic blasts from patient material, are performed to enable research in the field of pediatric acute leukemia. 67

68 SOLID TUMORS 68

69 NAAM: LAUREL TABE BATE-EYA Promovendus Naam Centrum: Academisch Medisch Centrum (AMC) Naam Research groep: Oncogenomics Abstract The anti-apoptotic B cell lymphoma proteins are highly expressed and have been shown to have an oncogenic role in numerous cancer types. BCL-2 is highly expressed in neuroblastoma tumors and previous data has shown that knockdown and inhibition of BCL-2 with shrna and small molecule inhibitor ABT263 induces an apoptotic phenotype in neuroblastoma cell lines. However, ABT263 is not BCL-2 specific and also inhibits BCL-X L and BCL-W leading to dose-limiting thrombocytopenia in patients treated with ABT263. In this study, we characterized the response of neuroblastoma cell lines and xenografts with high BCL-2 expression to the new and specific BCL-2 inhibitor ABT199. Additionally, we study the mechanisms of resistance in neuroblastoma tumors to ABT199 and ABT263 and how to overcome these resistance mechanisms with combinational therapy using chemotherapeutics, targeted compounds and drug delivery systems for new treatment regimens of neuroblastomas with high BCL-2 expression. 69

70 NAAM: Dr. W. Peter Bekkering of Postdoc Naam Centrum: Academisch Medisch Centrum / Emma Kinderziekenhuis Naam Research groep:orthopedie / Kinderoncologie AMC Dr. W. Peter Bekkering, Pediatric PT / PhD Department of Orthopaedics, Rehabilitation & Physical therapy Leiden University Medical Center / Willem-Alexander Children s hospital Postal zone: H0-Q, room C PO Box 9600, 2300 RC Leiden, NL +31 (0) (dept.) +31 (0) w.p.bekkering@lumc Academic Medical Center Amsterdam / Emma Children s hospital Po Box 22660, 1100 DD Amsterdam, NL +31 (0) w.p.bekkering@amc.uva.nl Abstract Achtergrond: Een grotere rol van de patiënt in de behandeling en actievere betrokkenheid bij de medische besluitvorming wordt door patiënten en beleidsmakers in de gezondheidszorg herhaaldelijk gepromoot. De huidige richtlijnen in kinderoncologische zorg, roepen zorgaanbieders daarom ook op om relevante informatie met hun jonge patiënten te delen en hun actieve deelname aan de besluitvorming te bevorderen. Vooral bij kwaadaardige bottumor chirurgie, waar meerdere chirurgische opties voorhanden zijn (variërend van extremiteit sparende tot ablatieve chirurgie) met een breed scala aan gevolgen voor de patiënt, is betrokkenheid van zowel de patiënt als zijn ouders in de besluitvorming van groot belang Tot op heden wordt gezamenlijke besluitvorming (Shared Decision Making) nog nauwelijks toegepast bij kinderen en adolescenten met een maligne bottumor. Doelstelling: Doel van deze studie is daarom het introduceren van Shared Decision Making (SDM) bij de besluitvorming voor de chirurgische interventie bij kinderen / adolescenten met een maligne bottumor. Uiteindelijk hopen wij hiermee de kwaliteit van leven en de tevredenheid van patiënt en ouders met de uiteindelijke keuze te kunnen vergroten. Methode: Het introduceren van Shared Decision Making zal worden uitgevoerd in vier stappen, 1. Evaluatie van waardering en betrokkenheid; 2. Productie van Decision Aids; 3. Implementatie van Shared Decision Making in de praktijk; en 4. Proces evaluatie Resultaat: De met deze studie verworven kennis over effectieve strategie componenten voor de implementatie van SDM bij kinderen en adolescenten met botkanker, kan ook worden benut voor de introductie van SDM bij andere (kinder)oncologische aandoeningen en voorkeur gevoelige beslissingen. Project leiding Dr. J.A.M. Bramer, Afd. Orthopedie, AMC Mw. Dr. L.C.M. Kremer, Afd. Kinderoncologie, Emma Kinderziekenhuis/AMC 70

71 NAAM: Emmy Dolman Postdoc Naam Centrum: Academisch Medisch Centrum, Universiteit van Amsterdam Naam Research groep: Oncogenomics; Group Jan Molenaar Abstract Momenteel werk ik op het project genaamd: Preclinical valdiation of targeted drugs and rational drug combination design for pediatric high risk neuroblastoma and acute lymphoblastic leukemia. Mijn focus binnen dit project ligt op het (mede) opzetten en uitvoeren van in vitro en in vivo studies waarin we de effectiviteit van kandidaatgeneesmiddelen voor de behandeling van neuroblastoma onderzoeken. Ik evalueer de in vivo farmacokinetiek van de kandidaatgeneesmiddelen om een link te kunnen leggen tussen effectiviteit en intratumorale geneesmiddelconcentraties. Verder focus ik mij op het vinden en valideren van biomarkers voor effectiviteit, maar ook voor het in- of excluderen van patiënten. Om de klinische implementatie van veelbelovende kandidaatgeneesmiddelen te verbeteren, onderzoek ik tevens of de middelen gecombineerd kunnen worden met de huidige geneesmiddelen die gebruikt worden voor de behandeling van neuroblastoompatiënten en/of de werking van de kandidaatgeneesmiddelen verbeterd kan worden door combinatie met een tweede geneesmiddel. 71

72 NAAM: Thomas Eleveld Promovendus Naam Centrum: AMC Naam Research groep: Oncogenomics; Group Jan Molenaar Abstract I am working on the project Identification and validation of acquired genomic aberrations involved in neuroblastoma tumor evolution. In neuroblastoma, primary tumors often respond quite well to therapy, however, relapse occurs frequently and these tumors become refractory to therapy. In this project we compare whole genome sequencing results of neuroblastoma relapse tumors to that of the corresponding primary tumors to identify mutations that are associated with this resistant and aggressive behaviour. We are focussing on mutations that occur de novo or are enriched in the relapse tumors compared to the primary tumors. To gain insight into the role of the mutations in relapse formation we characterize these mutations in vitro and in vivo and link them to novel targeted inhibitors that can be used as new treatment options for neuroblastoma relapse tumors. We have recently identified an enrichment in mutations affecting the RAS-MAPK pathway, such as loss of NF1 and activating mutations in RAS and ALK, in neuroblastoma relapses. These mutations were also present at high frequency in a panel of neuroblastoma cell lines, and the presence of these mutations can be used as a biomarker for sensitivity to MEK inhibition. We are currently investigating the role of increased RAS-MAPK signalling in in neuroblastoma, as well as the use of MEK inhibitors in the treatment of aggressive and/or relapsed neuroblastoma. 72

73 Naam: Saskia Gooskens Promovendus, MD Naam centrum: Erasmus MC Sophia Kinderziekenhuis / Prinses Máxima Centrum voor Kinderoncologie Naam research groep: Renal tumours Supervisor: Dr. M.M. van den Heuvel-Eibrink, H.van Tinteren, R.Pieters Pasfoto: Research interesses/expertises (trefwoordsgewijs, max.50 woorden): Pediatric renal tumours Clear Cell Sarcoma of the Kidney Beschrijving eigen research project (max. 250 woorden): The most common childhood renal tumour is Wilms tumour. Other types of renal cancer occur in less than 10% of the children with a renal tumour. This research project is focussed on Clear Cell Sarcoma of the Kidney, the most commonly occurring non-wilms renal tumour in children [1]. Clinical- as well as biological data on this specific renal tumour are scarce in literature. The first phase of this project was focused on clinical characteristics of CCSK. By using the data of the international SIOP database ( ), clinical characteristics and outcome of de novo, as well as relapsed CCSK patients were analysed [2,3]. This project additionally includes comprehensive molecular characterization of CCSK using next generation sequencing, in collaboration with the American TARGET project, an initiative of the National Cancer Institute (NCI). The goal of this study is to identify recurrent pathogenetic changes that are involved in the development or progression of CCSK, in order to identify prognostic markers and target for new, more effective, therapy. The overall goal of this research project is to find clues for improvement of future international treatment protocols for children with CCSK, and in a later phase also for children with other types of non-wilms renal tumours. 73

74 NAAM: Tim van Groningen Promovendus Naam Centrum: Academisch Medisch Centrum (AMC), Amsterdam Naam Research groep: Oncogenomics Abstract Most high stage neuroblastoma initially respond to chemotherapy, but ultimately relapse as therapy-resistant tumor. The mechanisms driving relapse and resistance remain elusive. We studied intratumor cellular heterogeneity with respect to drug sensitivity and expression of developmental pathways. We identified phenotypically divergent cell types within neuroblastoma. These cellular subtypes are markedly distinct with respect to neuroblastoma markers and activation of signalling routes. Importantly, some cell types have superior resistance to a wide variety of chemotherapeutics used in the clinical management of neuroblastoma. We developed protein markers for identification of these drug-resistant cells in vivo. These analysis identified a small minority of these drugresistant cells in primary human neuroblastoma. Importantly, these drug-resistant cells were strongly enriched in post-chemotherapy samples and in relapsed neuroblastoma. We identified a transcription factor network and a variety of signalling routes like WNT, NOTCH, TGFβ and PDGF, associated with the chemo-resistant phenotype. Manipulation of several candidate transcription factors from this network induced a transition of neuroblastoma cells to the chemo-resistant phenotype, including alteration of many developmental signalling routes. Thus, new therapeutic strategies targeting these developmental signalling routes are required to provide a clinical perspective to eradicate these multi-drug resistant tumor cells. 74

75 NAAM: Anne Hakkert Promovendus Naam Centrum: Academisch Medisch Centrum (AMC) Amsterdam Naam Research groep: Oncogenomics; Group Jan Molenaar Abstract Neuroblastoma is a childhood tumour with low survival rates. Whole Genome Sequencing of 87 neuroblastoma tumours (Molenaar, Nature 2012) revealed abortions in genes involved in DNA repair. In this project, several actionable genes will be evaluated, including BRCA1 methylation and DNA-PKcs. The first aim of this project is to study a specific mutation pattern of predominately Cytosine to Adenine (CtoA) mutations. This mutation type is unique for neuroblastoma. CtoA mutations arise under oxidative stress, due to the oxidation of Guanine, leading to 8-OxoGuanine. DNA copy number analysis shows chromosomal losses of the glycosylases involved in the repair of the CtoA mutations (OGG1, MUTYH and MTH1). In addition to the copy number losses, we also find damaging mutations in these genes. And most importantly there is a correlation between the CtoA phenotype and loss of the glycosylases. Recently, MTH1 inhibitors were identified (Helleday, Nature 2014). These MTH1 inhibitors will be tested in neuroblastoma xenografts, including an orthotopic model, derived from the TIC-lines. 75

76 NAAM: Lianne Haveman X Klinische-fellow research Naam Centrum: AMC Amsterdam Abstract Project leaders: Dr JHM Merks, Dr H van den Berg In current clinical practice a number of dilemmas about the diagnosis and treatment of patients with Ewing sarcoma (ES) are frequently discussed. In high risk ES patients (patients with metastatic or recurrence of disease), patients are frequently treated with high dose chemotherapy (HDC) followed by autologous stem cell rescue. The treatment is associated with severe toxicity, however the effectiveness of this treatment is controversial. Two Cochrane reviews are being performed to see if HDC improves event free survival (EFS) and overall survival (OS). In the diagnosis of Ewing sarcoma, the use of fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) computed tomography (CT) (FDG-PET CT) is increasingly used. The added value in the standard diagnostic work up in patients with ES has to be evaluated. By performing a diagnostic Cochrane review we try to give an answer if the use of FDG-PET CT in the staging of ES leads to a higher sensitivity and specificity in the diagnostic and staging process. ES most of the time arise from the bone and soft tissue. Extra-osseous ES commonly involves the paravertebral regions of the spine and has only infrequently been described to primarily involve the central nervous system. In this study based on data available in the international coordinating centre for ES, more knowledge about incidence, prognosis and possible factors which correlate with outcome in cerebral ES and ES of the cranial bones is examined. There is very little information concerning the radiological tumour response in ES and the impact on prognosis. The aim of this study is to assess the radiological tumour response at different time points and to determine the prognostic value by correlating tumour volume response to event free survival (EFS), OS and with relapse of disease by using data of the international coordinating centre for ES. 76

77 NAAM: Jan Koster Groepsleider Naam Centrum: AMC Naam Research groep: Oncogenomics, subgroep bioinformatica Research interesses/expertises (trefwoordsgewijs, max.50 woorden): Bioinformatica, high throughput analyses, microarray, mrna expressie, mirna, acgh, Whole genome sequencing, SNP array, methylering array, webbased tools, chip-chip/seq, transcriptie factor binding, genomics, netwerken, integrative analyses, statistiek, R/bioconductor, data mining, neuroblastoma, medulloblastoma, programmeren, databases, R2 platform, Abstract: Als subgroep binnen de afdeling oncogenomics houdt de bioinformatica groep zich bezig met alle aspecten van de verwerking van high throughput data die binnen de afdeling gegenereerd wordt (van microarrays, tot whole genome sequencing ).Wij dragen zorg voor het aanbieden van analyseerbare datasets, ondersteunen/helpen met de analyses en ontwikkelen software die het mogelijk maakt dat bio-medische wetenschappers zelf inzicht kunnen krijgen in hun eigen data ( Daarnaast hebben we expertise in het opzetten van databases, doen we transcriptie factor binding site analyses en proberen we inzicht te verkrijgen in biologische processen door middel van netwerk analyses. Dit alles doen we in nauwe samenwerking met de onderzoekers. 77

78 NAAM: Jeroen Middelbeek Postdoc Naam Centrum: RadboudUMC Naam Research groep: Lab Pediatric Oncology Abstract Targeting cytoskeletal dynamics to stabilize neuroblastoma progression Neuroblastoma is one of the most common malignancies in childhood. Survival rates are excellent for low- and intermediate risk neuroblastomas. However, high risk neuroblastomas frequently present with metastatic disease at diagnosis and require more intensive treatment regimens. Unfortunately, many of these patients respond poorly to treatment or relapse due to acquired therapy resistance. Despite major improvements in treatment of neuroblastoma, there are generally no curative therapies for relapsed metastatic disease and only ~5% of the high-risk patients survives long term after relapse. Current research aims to identify novel therapeutic targets and to develop novel therapeutic strategies to stabilize metastatic neuroblastoma. Neuroblastoma progression is strongly influenced by environmental cues, such as the mechanical properties of the surrounding tissue. The physical cross-talk between tumor cells and the microenvironment is mediated by cell adhesion sites and cell protrusions that modulate cell motility and differentiation. As the formation of these structures depends on the spatiotemporal regulation of the actomyosin cytoskeleton in response to environmental cues, the cytoskeletal proteins and signaling pathways involved are considered potential therapeutic targets. Members of the Transient Receptor Potential (TRP) cation channel family, including TRPM7, play key roles in the ability of cells to sense and respond to their environment. Tethered to the cytoskeleton, TRP channels modulate cytoskeletal organization in response to chemical and physical stimulation, and control cell motility and differentiation. TRPM7, a Ca 2+ -permeable TRP channel, localizes to sites of cell adhesion and regulates cytoskeletal dynamics in response to various stimuli, including mechanical stress. Using multiple neuroblastoma cell models, we demonstrated that expression of TRPM7 is closely associated with the migratory and metastatic properties of neuroblastoma cells, both in vitro and in vivo. Moreover, TRPM7 associates with a cytoskeletal protein complex of which many components strongly associate with neuroblastoma progression in patients. Consistent with the idea that adhesion signaling and cytoskeletal dynamics control cellular differentiation, microarray based expression profiling on control and TRPM7 shrna transduced neuroblastoma cells indicate that TRPM7 controls a developmental transcriptional program that involves the SNAI2 transcription factor. Overall, these data strongly support a role for TRPM7 and its interacting partners in cytoskeletal remodeling and, consequently, neuroblastoma progression. 78

79 NAAM: Jan Molenaar Groepsleider Naam Centrum:AMC Naam Research groep: Oncogenomics; group Jan Molenaar Abstract The aim of my research group is to set up an evidence based personalized medicine approach for pediatric solid tumors. Therefore we have started two different projects for across tumor analysis. First we are setting up an validation pipeline for actionable genes and corresponding targeted compounds across pediatric tumors within the European organized ITCC biology network. We are using a combination of high throughput profiling and in vitro validation with a robotics based screening facility. Secondly we are aiming at a full biological characterization of pediatric relapse tumors within the ither project. We are generating a system by which each pediatric cancer patient will be assigned specific therapeutic options based on the molecular biological characteristics of its specific tumor. This approach is now best developed for neuroblastoma tumors and this will be used as a blueprint for the other tumor types. In neuroblastoma we have performed extensive characterization of primary and relapse tumors We are currently performing in vitro and in vivo validations for the following targets and compounds: BCl2 (ABT199), CDK2 (AT7519), MTH1 inhibitors (TH588) and MEK inhibitors (Cobimetinib, Binimetinib and Trametinib). Our preclinical data is used in collaboration with Roche and Abbvie for clinical trial proposals for Cobimetinib and ABT199 respectively. 79

80 NAAM: Johan van Nes Postdoc Naam Centrum: Academisch Medisch Centrum (AMC), Amsterdam Naam Research groep: Oncogenomics Abstract Most high stage neuroblastoma initially respond to chemotherapy, but ultimately relapse as therapy-resistant tumor. The mechanisms driving relapse and resistance remain elusive. We studied intratumor cellular heterogeneity with respect to drug sensitivity and expression of developmental pathways. We identified phenotypically divergent cell types within neuroblastoma. These cellular subtypes are markedly distinct with respect to neuroblastoma markers and activation of signalling routes. Importantly, some cell types have superior resistance to a wide variety of chemotherapeutics used in the clinical management of neuroblastoma. We developed protein markers for identification of these drug-resistant cells in vivo. These analysis identified a small minority of these drugresistant cells in primary human neuroblastoma. Importantly, these drug-resistant cells were strongly enriched in post-chemotherapy samples and in relapsed neuroblastoma. We identified a transcription factor network and a variety of signalling routes like WNT, NOTCH, TGFβ and PDGF, associated with the chemo-resistant phenotype. Manipulation of several candidate transcription factors from this network induced a transition of neuroblastoma cells to the chemo-resistant phenotype, including alteration of many developmental signalling routes. Thus, new therapeutic strategies targeting these developmental signalling routes are required to provide a clinical perspective to eradicate these multi-drug resistant tumor cells. 80

81 NAAM: Kathelijne Kraal Promovendus Naam Centrum: Prinses Máxima Centrum voor Kinderoncologie Naam Research groep: Neuroblastoom, Optimising targeted radiotherapy with 131 I-MIBG therapy for neuroblastoma patients. KIKA funded. Abstract 131 I-MIBG therapy (Overall) The best clinical setting for administering 131 iodine(i)-metaiodo-benzylguanidine (MIBG) therapy has not been ascertained yet. The efficacy of 131 I-MIBG therapy is described ranging from 30-60% in all patient groups, demonstrating a higher response rate in the upfront setting compared with the relapse setting. Various studies report on the outcome of refractory NBL patients, with an objective response rate (ORR) between 18-31%. We will analyze the 131 I-MIBG data in 3 separate studies: A. 131 I-MIBG and hyperbaric oxygen, vitamin C and the effect on oxygen radical formation. B. 131 I-MIBG therapy and Topotecan combination therapy (AMRO-NB-HR-2000/01). C. Upfront 131 I-MIBG therapy and N5/ N6 (standard arm NB 2004 protocol); a pilot- and current study. Patients with intraspinal NBL and long term functional outcome. Neuroblastoma patients with intraspinal extension may present asymptomatically or by neurological deficit, early diagnosis and prompt treatment is of critical importance. The treatment options include chemotherapy, neurosurgical decompression and radiotherapy. They are all effective for a prompt relief of epidural compression, but there is no consensus on the best treatment. This patient group will be analysed in 3 projects: A. Prospective Study (International) registry on children with peripheral Neuroblastic Tumor with spinal canal involvement protocol (NB-SCI), SIOPEN consortium. The study registry is currently being implemented in the Netherlands with the aid of the Dutch Childhood Oncology Group (DCOG). Registration can start as of the end of B. Neuroblastoma with intraspinal extension: late adverse events in long-term survivors. C. Systematic review: patients with intraspinal extension (IE) neuroblastoma (NBL). 81

82 NAAM: Tytgat GAM Postdoc Naam Centrum: AMC Naam Research groep: solid tumors: Neuroblastoma. TRANSLATIONELE TUMOR BIOLOGIE a PCR BASED MRD DETECTION IN NEUROBLASTOMA Principal Investigator(s): Lieve (G) AM Tytgat Senior investigator(s): prof dr. C ellen van der Schoot; prof dr. Huib Caron PhD student (s): Esther van Wezel / Janine Stutterheim b: PRE-CLINICAL SCREENING OF DRUG COMBINATIONS FOR NEUROBLASTOMA. OPTIMISING CURRENT TREATMENT MODALITIES THROUGH TARGETING THE PI3K/AKT PATHAY. Principal Investigator(s): dr. Andre B.P. van Kuilenburg, dr. Lieve (G)AM. Tytgat Senior investigator(s): prof dr. Huib N. Caron c: ANALYSIS OF NEUROBLASTOMA TUMOR GROWTH AND METASTASES PATTERNS ON MIBG SCANS Principal Investigator(s): dr. Lieve (G) AM. Tytgat Senior investigator(s): prof dr. Huib N. Caron; prof dr. Berthe van Eck-Smit, PhD student (s): drs. Gitta Bleeker d: CIRCULATING TUMOR CELLS IN NEUROBLASTOMA Principal Investigator(s): Lieve (G) AM Tytgat Senior investigator(s): prof dr. C ellen van der Schoot; prof dr. Huib Caron PhD student (s): Jalenka van Wijk e: Klinische aspecten van 131I-MIBG therapie voor neuroblastoma. Principal Investigator(s): Lieve (G) AM Tytgat, Senior investigator(s): prof dr. Huib Caron, Ann Smets dr. MM van Noesel, dr. HJH van der Pal, Prof. Dr. BLF. van Eck-Smit, dr EC. Van Dalen PhD student (s): Kathelijne Kraal 82

83 f: Chirurgie bij het Neuroblastoom Principal Investigator(s): S.Zwaveling dr.; Lieve (G) AM Tytgat, Senior investigator(s): M. Wijnen dr., MM van Noesel, dr. PhD student (s): M Jans. Abstract A: Ontwikkelen van optimale RNA panel, om Minimale residuale ziekte (MRD) bij het neuroblastoom te meten (prospectieve trial). Verder het gebruik van DNA markers als PCRgebaseerde MRD marker. B: onderzoek naar optimale drug combinaties in combinatie met remmers van de PI3K/AKt pathway om zo optimaal effect te genereren: preklinische model studie. Nadat een in vitro model systeem opgezet is van verschillende neuroblastoom cell lijnen, worden bekende chemotherapeutica gecombineerd met een panel van PI3K/Akt remmers. Vervolgens wordt van succesvolle combinaties, de signal transductie onderzocht in diverse cellijnen. C: Isoleren van circulerende tumor cellen (CTC s) uit Beenmerg of bloed. Onderzoek naar optimale techniek, verdere karakteriseren van de cellen (single cell) op basis van specifieke eigenschappen, bv DNA aberraties etc. Het doel: kunnen deze cellen als een vorm van vloeibaar tumor biopt gebruiken? D: Door 123I-MIBG scans bij diagnose te scoren, hebben we gekeken naar het aantal lichaam segmenten wat aangedaan is (extensie) en de vorm van de metastasen: Focale laesies versus diffuse uitbreiding. Dit resulteert in 2 grote patronen van metastasering: patiënten met alleen focale laesies, met weinig lichaams segmenten (mediaan 2), en patiënten met meer diffuse lesies met meer lichaams segmenten (mediaan 9). E: klinisch effect van 131 I-MIBG als behandeling bij het neuroblastoom. Behandeling en spontaan beloop bij patiënten met een stadium 4S neuroblastoom. Klinisch beloop en lange termijn effecten van het hebben van een neuroblastoom met intra spinale groei (Dumbell neuroblastoom). F: Onderzoek naar effecten van chirurgie van het neuroblastoom: retrospectieve analyse van morbiditeit en mortaliteit. 83

84 NAAM: Jalenka van Wijk / Promovendus Naam Centrum: Kinderoncologie AMC / Experimentele Imuunohematologie (IHE) Sanquin Identification of heteregeneity between and within neuroblastoma patients at the level of circulating tumor cells and extracellular vesicles. Jalenka van Wijk 1,2, Esther M. van Wezel 1,2, Jan Koster 3, Johan van Nes 3, Lily Zappeij- Kannegieter 1, Rogier Versteeg 3, Huib N. Caron 2, C. Ellen van der Schoot 1, Godelieve A.M. Tytgat 2 1. Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands 2. Department of Oncogenomics, Academic Medical Center, Amsterdam, The Netherlands 3. Department of Pediatric Oncology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands Introduction: Circulating tumor cells (CTCs) in pediatric neuroblastoma tumors are, together with disseminated tumor cells in the bone marrow, detected by immunocytology and RQ-PCR. However, these techniques are unable to characterize heterogeneity at the cellular level. Since neuroblastoma shows high heterogeneity between and within tumors we believe possible subpopulations of CTCs might exist. These subpopulations could have a difference in drug response or metastatic potential, therefore affecting prognosis. Aim: To develop a multicolour flow cytometry panel of antibodies consisting of a backbone panel identifying all neuroblastoma cells in blood and bone marrow, and additional heterogeneity markers to detect subpopulations between and within patients. In addition, we are investigating the characteristics of extracellular vesicles (EVs) released by neuroblastoma tumors and their possible application in disease monitoring. Methods: Possible backbone markers were identified by literature research and bioinformatical analysis on tumors, primary tumor cell lines (PTCs) and cell lines. Candidate markers were confirmed with flow cytometry. Results: We identified six new potential backbone markers for the detection of all neuroblastoma cells; EBAG9, CDH2, IL6ST, ITGAV, RAP1A and CKAP4. Conclusion: The combination of markers commonly used in literature (CD45 -, CD56 +, CD81 + and CD9 + ) might not detect all neuroblastoma cells, since these markers were differentially expressed or even absent on cell lines and PTCs. A backbone panel with the new identified markers might be the first step in detection of distinct subpopulations in blood and bone marrow. Ongoing work: Identification of heterogeneity markers for use in flow cytometry and characterization of EVs, from cell lines, PTCs and patient material, is ongoing. We are currently analyzing the presence of cell free tumor DNA in plasma of patients as well. Combining all results will increase insight into neuroblastoma progression over time and factors contributing to outcome. 84

85 Promovendus Naam Centrum: Radboudumc Naam Research groep: Laboratory of Pediatric Oncology Abstract Cytoskeletal regulation in high risk neurobastoma High-risk neuroblastoma patients frequently present with metastatic disease at diagnosis and often relapse due to acquired therapy resistance. To effectively treat these high-risk neuroblastomas, we need to better understand mechanisms driving neuroblastoma progression and therapy resistance. Recent studies have shown that, in addition to trophic factors, biophysical properties of the tumor microenvironment influence neuroblastoma progression. Mechanical cues derived from the tumor microenvironment are sensed and translated into cellular responses by cell adhesion sites. The formation and function of these structures depends on the spatiotemporal regulation of the actomyosin cytoskeleton, modulating cell motility and differentiation. Hence, cytoskeletal proteins and their upstream regulators are considered potential therapeutic targets. My project involves studying the role of actin dynamics in neuroblastma disease progression. Recently, we showed that TRPM7, a Ca 2+ -permeable cation channel that regulates cytoskeletal dynamics in response to environmental cues, controls migratory and metastatic properties of neuroblastoma cells both in vitro and in vivo. However, how TRPM7 regulates these processes remains unclear. By mass spectrometry, we demonstrated that TRPM7 is part of a cytoskeletal protein complex of which many components associate with neuroblastoma disease progression. By combining a variety of in vitro methods, including 3D cultures, and in vivo neuroblastma xenograft models, we are currently exploring how these interactors affect neuroblastoma cell behavior and differentiation. We expect that detailed insights into these regulatory circuits will identify targets for therapeutic intervention in these high risk neuroblastomas. 85

86 BRAIN TUMORS 86

87 NAAM: Eleonora Aronica Groepsleider Naam Centrum: Academisch Medisch Centrum (AMC/UVA) Naam Research groep: Neuropathologie Abstract Laaggradige hersentumoren bij kinderen: pathogenese en epileptogenese In onze onderzoeksgroep zijn we geïnteresseerd in de genetische eigenschappen van laaggradige hersentumoren bij kinderen, zoals glioneuronale tumoren en subependymale giant cell astrocytomen (SEGA). Glioneuronale tumoren (GNTs) zijn de meest voorkomende tumoren bij kinderen met medisch onbehandelbare epilepsie. GNTs bestaan uit een mengsel van dysplastische neuronen en neoplastische gliale cellen. Er is weinig bekend over de specifieke genetische veranderingen en correlatie met recidief en maligne transformatie van verschillende histologische subtypen van GNTs.. SEGA zijn laaggradige hersentumoren die bij kinderen en adolescenten met Tubereuze Sclerose Complex (TSC) voorkomen en zijn een belangrijke oorzaak van de snelle neurologische achteruitgang en overlijden. Een beter inzicht in de biologische mechanismen die leiden tot abnormale groei en maligne transformatie van deze tumoren kan bijdragen tot een betere diagnostische classificatie die gebruikt kan worden voor risicostratificatie en behandeling. Onze onderzoeksgroep is ook geïnteresseerd in de biologische processen die de epilepsie veroorzaken bij kinderen met hersentumoren. Zo blijken bijvoorbeeld subtiele ontstekingsprocessen een rol te kunnen spelen bij de ontwikkeling van epilepsie. Inzicht in de rol van kleine regulerende moleculen (mirnas) zou in de toekomst van belang kunnen zijn bij het ontwikkelen van nieuwe therapieën. Uiteraard is het van groot belang om een internationaal multidisciplinair netwerk te hebben met samenwerking tussen clinici en wetenschappers, waardoor er in de toekomst een betere diagnose gesteld kan worden. Een grote uitdaging voor de toekomst is om de behandeling van kinderen met laaggradige hersentumoren te personaliseren met behulp van meer specifieke therapieën gericht op moleculaire doelwitten in de tumorcel. 87

88 NAAM: Sophia Bruggeman Groepsleider Naam Centrum: UMCG Groningen Naam Research groep: Pediatric Oncology Epigenetics and genomic instability in pediatric brain cancer Irena Bockaj, Marlinde Smit, Eveline de Bont, Sophia Bruggeman Brain cancer is the main solid tumor in childhood. In the Netherlands, each year more than a hundred children are newly diagnosed with brain cancer. Approximately seventy percent of these children are being cured, yet anti-tumor treatment causes brain damage that leads to severe persisting side effects in survivors. Therefore, there is an urgent need for improved therapies exclusively targeting the tumor cell. Our lab focuses on the role of epigenetics and genomic instability in the pediatric brain cancers medulloblastoma and glioma. Within this context, we have a strong interest in the relationship between normal brain development and cancer, as many childhood cancers arise from tissues that are not yet fully differentiated. Using a number of in vitro and in vivo models for pediatric brain cancer and their respective cells of origin, we are trying to understand how changes to the epigenome, for instance caused by mutations in chromatin modifying genes but also changes that naturally occur during development, contribute to the initiation and progression of pediatric brain cancer. Since alterations in the epigenome are in principle fully reversible, this research will be promising for the development of novel pediatric brain cancer treatments. 88

89 NAAM: Esther Hulleman Groepsleider X Naam Centrum: VU medisch centrum Naam Research groep: Lab kinderhersentumoren / Neuro-oncology Research group Abstract The pre-clinical brain tumor research at the department of Pediatric Oncology at the VU University Medical Center focuses on developing targeted therapies for children with a malignant brain tumor. In particular, we aim to ameliorate survival and to decrease shortand long-term side effects by identifying novel drugs and drug targets, and by improving in vitro sensitivity to chemotherapy and irradiation. The research laboratory is embedded in the Neuro-oncology Research Group (NRG) at the Cancer Center Amsterdam (CCA), a collaborative effort of the departments of Neurosurgery, Neurology, Pathology, and Pediatric Oncology. The NRG consists of both clinicians and molecular biologists, and combines adult- and pediatric brain tumor research. Currently, research at the pediatric brain tumor laboratory focuses mainly (but not exclusively) on medulloblastoma and highgrade glioma, including diffuse intrinsic pontine glioma (DIPG). For these tumor types, various cell- and animal models have been set up, using primary tumor material that is collected routinely in collaboration with the Neurosurgical Center Amsterdam, or through a nationwide brainstem glioma autopsy protocol in collaboration with the department of Pathology. Besides the experimental brain tumor models, our group focuses on blood diagnostics (liquid biopsies), functional profiling, and drug screens. 89

90 NAAM: Hans Meel Promovendus Naam Centrum: VUmc Cancer Center Amsterdam Naam Research groep: Pediatric Neuro-Oncology Abstract: Identification of synergistic targeted drug combinations by phospho-rtk and phosphokinase profiling of DIPG cells Despite the high frequency of genetic aberrations involving receptor tyrosine kinases such as EGFR and PDGFR, treatment with targeted inhibitors to these receptors has been unsuccessful in diffuse intrinsic pontine glioma (DIPG) patients. We determined the sensitivity of 10 primary DIPG cell lines to a selection of small molecules, each with a different set of targeted kinases. In line with clinical experience, monotherapy with agents against PDGFR, EGFR, c-met or VEGFR was not effective at clinically relevant concentrations. To elucidate the causes for the observed drug resistance, we determined the phosphorylation status of the majority of relevant receptor tyrosine kinases (RTKs) and their downstream effectors after drug treatment, using antibody arrays. After 24 hours, treatment with canertinib (pan-egfr inhibitor), dasatinib (PDGFR and Src-inhibitor) or trametinib (MEK inhibitor) at non-cytotoxic concentrations resulted in an upregulation of unblocked RTKs and their downstream effectors in cells treated with either of the aforementioned inhibitors. In non-treated cells, we observed co-activation of multiple RTKs and their respective intracellular pathways, which poorly correlated with underlying genetic aberrations. Combined treatment with inhibitors to co-activated and/or reciprocally upregulated RTKs proved to be strongly synergistic in vitro at clinically relevant concentrations. We therefore hypothesize that targeted therapies for DIPG should consist of multiple inhibitors and should be based on phospho-protein profiling of tumors, instead of their genetic make-up. 90

91 NAAM: Avanita Prabowo Promovendus Naam Centrum: Academisch Medisch Centrum (AMC/UVA) Naam Research groep: Neuropathologie Abstract Title: Molecular features of pediatric low-grade glioneuronal tumors Glioneuronal tumors (GNTs), such as gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNETs) are low grade, slowly growing tumors, representing the most frequent tumor entities in children undergoing surgery for chronic intractable focal epilepsy. Although recurrence and/or malignant transformation of GNTs is rare, it has been documented for GGs that they may undergo malignant transformation in their astroglial component. Only little is known about malignant transformation of DNET and about the specific genetic alterations associated with GNTs or correlated with their recurrence and malignant transformation. Improving the criteria for a better recognition of different entities within the GNT spectrum and particularly distinction of diffusely growing WHO grade I GNTs ( GNT-diffuse type ) from grade II tumors is essential to ensure efficient best-practice management of these tumor entities. Moreover, uncontrolled tumor-related epilepsy affects a child's quality of life, influencing the development of basic cognitive and behavioural skills. Thus control of spontaneous seizures should be also considered as primary treatment target in order to reduce the risk for progressive cognitive impairment or adverse effects of medication. The aim of this study is to identify DNA copy number aberrations (CNA) at a genome-wide scale, to evaluate the prevalence of point mutations in candidate genes, as well as to identify the molecular alterations underlying the tumor epileptogenicity in a large spectrum of GNTs. Understanding common biologic pathways involved in the etiopathogenesis and epileptogenesis of GNTs represents an essential basis for a correct diagnosis and the development of personalized therapeutic strategies. 91

92 NAAM: AYN Schouten-van Meeteren XXX Postdoc XX Klinisch-projectleider Naam Centrum: Emma Children s Hospital AMC Naam Research groep: PANDA : Abstract): Project design and co-worker in divers multidisiciplinary projects concerning pediatric neuro-oncology and palliative care. For neuro-oncology the field of attention is low grade glioma (chair SIOP committee) Focus pediatric brain tumors: improving survival as well as reducing physical, psychosocial, neurocognitive consequences on short and long term. PRISMA study:.efficacy of neuro-feedback in PBTS: randomized controlled trial and exploring insights in neuro-cognition after a brain tumor. (PI MA Grootenhuis) Low grade glioma understanding Characterization of genetic aberrations in pediatric low-grade glioneuronal tumors (PI E Aronica) CatMycMedullo: feasibility risk stratification medulloblastoma based on molecular biology. DETECT study endocrine outcome in the first 5 years after a pediatric brain tumor (PI H van Santen pediatric endocrinologist to be financed ). Visual outcome study in design: visual outcome after a childhood brain tumor in the Netherlands. (cooperation SM Imhof - ophthalmologist) PANDA Study the effect of Pediatric ANticipated and Dedicated care bridging the gap between hospital and home with transmural casemanagement. 92

93 NAAM: Lot Sewing Promovendus Naam Centrum: VUMC Naam Research groep: Neuro-Oncology Research group Abstract New therapeutic strategies for diffuse intrinsic pontine glioma (DIPG) are desperately needed. This research project focuses on translational research to aid the design of clinical trails in children. We are currently studying preclinical convection enhanced delivery (CED) in murine DIPG models, drug delivery to the brain(tumor) using position emission tomography and blood based detection of somatic mutations. The presence of the bloodbrain barrier (BBB) is a major limiting factor in the treatment of brain tumor patients, as it hampers the delivery of chemotherapeutics. A preclinical study using PET imaging showed distribution of bevacizumab to orthotopic DIPG models to be inadequate, where subcutaneous tumors established with same cells had high accumulation of this drug. This data underlines the importance of studying drug distribution to the brain before starting a clinical trial in patients, and the need for alternative drug delivery methods, such as CED. Our research has shown preclinical CED in murine DIPG models to be safe and reproducible. However, drug toxicity appears to be dependent on the location in the brain, since local delivery of drug concentrations that are safe in the thalamus and striatum show severe clinical toxicity when delivered to the brainstem. This should be considered when designing clinical trials with CED for children with DIPG. Our last project focuses on bloodbased detection of histon 3 mutations in DIPG using deep amplicon sequencing. Designing non-invasive detection methods will enable the start of targeted therapy based on mutational profile, without the need for invasive biopsy in these children. 93

94 NAAM: Sophie Veldhuijzen van Zanten Promovendus Naam Centrum: Naam Research groep: VU medisch centrum Diffuus Intrinsiek Ponsglioom (DIPG) team Pasfoto: Abstract Arts-onderzoeken op een klinisch promotie onderzoek naar Diffuus Intrinsiek Ponsglioom (DIPG) bij kinderen. Ziektebeeld: Gemiddeld 9 kinderen per jaar gediagnostiseerd in Nederland. Gemiddelde leeftijd 5-8 jaar. Geen curatieve behandeling beschikbaar. Progression Free Survival (PFS) 6 maanden, Median Overall Survival (MOS) 9 maanden. Lopende projecten: - Behandelstudie bij diagnose (radiotherapie 54 Gy, met gemcitabine in studieverband) - Behandelstudie bij progressie (bevacizumab, irinotecan, erlotinib en in de toekomst everolimus) - In ontwikkeling: behandelstudie bij progressie (lokale toediening van carmustine via Convection Enhanced Delivery) - Diagnostische PET studie met 89-Zirconium gelabeld bevacizumab (binnenkort ook in Londen) - Autopsie studie - Blood sampling studie - Literatuur en vragenlijst studie: Palliatieve zorg bij DIPG - Literatuur en vragenlijst studie: Corticosteroïd gebruik bij DIPG - Ontwikkeling van een Europese DIPG Registry en Imaging Repository 94

95 NAAM: Susanna Veringa Promovendus Naam Centrum: VU medisch centrum Naam Research groep: Kinderhersentumoren Abstract Description of research project Epigenetic therapies for pediatric high grade glioma PI: dr. Esther Hulleman & prof. dr. Gertjan Kaspers Although pediatric high-grade gliomas (HGG) represent a minority of cases, the management of these brain tumors is currently the most appalling challenge in pediatric (neuro-)oncology. Given the aggressive nature and lack of treatment options, these tumors are associated with an extremely poor prognosis [Broniscer et al., 2004]. Unfortunately, no chemotherapeutical regimen has successfully improved survival in these children yet. However, with a better understanding of increasing biological data, a more promising basis for future clinical trials may be established. It has already been demonstrated that there are marked differences in the molecular phenotype between pediatric and adult gliomas [Paugh et al, 2010]. More recently, insights from whole-genome sequencing studies identified unique selective pressures that are likely to promote tumorigenesis by genomewide epigenetic deregulation in the developing brain. Two histone mutations have been identified that affect methylation of histone 3: a missense mutation in the histone H3F3A, or histone 3.1 gene (HIST1H3B) at Lysine 27 (K27M), and a missense mutation in H3F3A at Glycine 34 (G34V/R) [Jones et al., 2012]. Interestingly, the K27M mutation is specific to midline tumors, such as thalamic gliomas and diffuse intrinsic pontine glioma (DIPG), while the G34V/R mutations are located at the cerebral hemispheres [Sturm et al., 2012]. Both mutations, however, are found to reduce the trimethylation mark of Lysine residues, and to dramatically change global methylationand gene expression patterns [Chan et al., 2013; Lewis et al., 2013; Bender et al., 2013; Bjerke et al., 2013]. As evidence is growing for a therapeutic potential of epigenetic modification in pediatric HGG, in this project we investigate the potential of epigenetic drugs for the treatment of pediatric glioma by screening of epigenetic drug libraries on a series of pediatric glioma cells, including cells with wild type- or mutant histone H3 variants. These drugs will be used either as monotherapy, or in combination with registered chemotherapeutic drugs and radiation therapy. Furthermore, the selected epigenetic drugs will be tested in combination with kinase inhibitors, since several receptor tyrosine kinases (RTKs) were found to be upregulated in pediatric HGG and DIPG [Paugh et al., 2010; Jones et al., 2012] and both classes of compounds may act synergistically. The most effective combinations will then be further investigated. 95

96 NAAM: Walderik W Zomerman w.w.zomerman@umcg.nl Promovendus Naam Centrum: Universitair Medisch Centrum Groningen Naam Research groep: Pediatric Oncology Kinomic profiling of pediatric medulloblastoma for the identification of novel potential targets Walderik W Zomerman 1, Sabine LA Plasschaert 1,2, Frank J Scherpen 1, Hassan Mahmud 1, Wilfred FA den Dunnen 3, Eelco W Hoving 4, Victor Guryev 5, Frank Johannes 6, Pieter Wesseling 7,8, Esther Hulleman 8, Eleonora Aronica 9, Eveline SJM de Bont 1 1 Department of Pediatric Oncology/Hematology, Beatrix Children s Hospital, University Medical Center Groningen, Groningen, The Netherlands; 2 Princess Maxima Center for Pediatric Oncology, Utrecht, The Netherlands; 3 Department of Pathology & Medical Oncology, Pathology Division, University Medical Center Groningen, Groningen, The Netherlands; 4 Department of Neurosurgery, University Medical Center Groningen, Groningen, The Netherlands; 5 Laboratory of Genome Structure and Ageing, European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; 6 Groningen Bioinformatics Center, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, The Netherlands; 7 Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands; 8 Department of Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; 9 Department of Neuropathology, Amsterdam Medical Center, Amsterdam, The Netherlands; Abstract Medulloblastoma progression is the result of a tumor cell growth advantage as a cause of altered cell signaling pathways. The alterations in cell signaling pathways can be due to genetic alterations, epigenetic modifications and/or micro-environmental interactions. Cellular signaling is caused by a cascade of activated proteins, which can be targeted by many different phospho-kinase inhibitors. Many of these inhibitors have entered clinical trials in a variety of cancers. Therefore, it is important to investigate the signaling through various protein kinase-mediated networks to identify novel potential targets for the treatment of medulloblastoma patients. In this study, we used high-throughput kinomic platforms to assess the kinase activity of 286 different peptides in 52 primary medulloblastoma samples from three different Dutch medical centers. The peptides correspond to phosphorylation sites of proteins involved in cellular signaling. Subsequently, we identified the most relevant active signaling pathways and signaling hubs in our medulloblastoma patient samples by mapping differentially activated peptides into networks. Analysis of peptide activities revealed a set of 169 differentially activated peptides in our medulloblastoma patient samples. Previously reported activity of ErbB family receptors, MET, PDGFRβ and VEGFR1-2 could be appreciated in our array results. Global network mapping of all differentially activated peptides confirmed the activity of PI3K/Akt/mTOR and RAF/MEK/ERK signaling pathways as prominent active signaling cascades in medulloblastoma. More interestingly, network mapping of sets of highly activated peptides identified PLCγ1 and CREB1 peptides as important signaling hubs. These signaling hubs showed the highest number of associations within the sets of highly activated peptides in our data. In conclusion, our high-throughput kinomic approach in combination with network mapping enabled us to confirm the activity of relevant signaling pathways associated with medulloblastoma. Moreover, we identified PLCγ1 and CREB1 as novel highly activated signaling hubs in medulloblastoma signaling. Signaling hubs are assumed to be the key regulators of activated signaling pathways and could guide us to novel potential targets for the treatment of medulloblastoma. Further investigations are warranted. 96

97 IMMUNOTHERAPIE 97

98 NAAM: Rick Admiraal Promovendus Naam Centrum: Naam Research groep: UMC Utrecht LUMC Leiden Leiden Academic Center for Drug Research (LACDR) Pediatric Blood and Marrow Transplantation Program Abstract Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment option for high risk and relapsed leukemia s as well as benign disorders. In order to prevent graft-versus-host-disease (GvHD) and rejection following HCT, patients receive ATG (Anti- Thymocyte Globulin) as part of the conditioning regimen. Side effect of ATG include delayed T-cell reconstitution (immune reconstitution, IR) following HCT, possibly leading to viral reactivations or relapse of malignancy. While using the standard dosing regimen, ATG serum concentrations are unpredictable leading to unpredictable (side) effects. We developed a population pharmacokinetic/pharmacodynamic (PK/PD) model for ATG to be able to account for differences in PK and PD between patients thereby optimizing ATG dosing. Based on concentration samples and clinical data from 280 children receiving a HCT in the LUMC (Leiden) and UMCU (Utrecht), a validated population PK-model was developed. We found peripheral blood lymphocyte counts before ATG dosing and body weight to influence ATG clearance, the latter in a non-linear relation. Using the PK-model, various individual exposure measures were calculated and related to clinical outcome data. Post-HCT AUC of ATG was a strong predictor for IR, which in turn predicted overall survival (OS), nonrelapse mortality and relapse mortality. In subgroups, a direct association was found between post-hct AUC and OS. While post-hct AUC did not predict the incidence of acute and chronic GvHD and rejection, this was significantly influenced by pre-hct AUC. In summary, using the PK-model and the optimal exposures, dosing of ATG will be amended to reach optimal pre- and post-hct AUC in all children. Timing of ATG relative to the graft infusion will also be amended, starting ATG 9 days before HCT (i.e. day -9) instead of the current day -5. We expect this individualized dosing regimen (clinical study starting April 2015) to lead to an improvement of IR and a decrease in GvHD and rejection, which could positively influence survival following HCT. In addition, a better predictable IR is of utmost importance for the optimal effect of adjuvant immunotherapies after HCT, as these rely on an optimal function of the immune system. 98

99 NAAM: Lynne M BALL L.M.Ball@lumc.nl Klinisch-projectleider Naam Centrum: Willem Alexander LUMC Naam Research groep: Stamcel transplantatie Supportive care werkgroep Onderzoek commissie Copromotor van PhD student Friso Kalkoen ivm MSC en MDS/JMML (KIKA project) 99

100 NAAM: JAAPJAN BOELENS Groepsleider Naam Centrum: UMC UTRECHT Naam Research groep: LAB BOELENS/NIERKENS Abstract Pediatrician Oncologist / Immunologist. Medicine (UMC Utrecht 1996), PhD in Amsterdam (University of Amsterdam/Academic Medical Center; 1999), trained as a paediatrician in Leiden (Leiden UMC)/Den Haag; Juliana Children s Hospital; 2004) followed by completion of clinical fellowship in immunology (2006; UMC Utrecht) and oncology (2011; ErasmusMC, Rotterdam). My clinical sub-specialization is Hemapoietic Cell Transplantation (HCT) and I am working as a consultant in HCT at the UMC Utrecht since I have a special interest in rare-diseases (as indication for HCT) in particular lysosomal storage diseases and finding strategies to get better disease control (in malignant diseases). My research group (Group Boelens / Nierkens: U-DANCE) focuses on the development of cord blood derived dendritic cell vaccines (anti-aml, anti-neuroblastoma). In addition there is a special interest designing a predictable low toxic conditioning regimen using PK/PD-models for e.g. TG (anti-thymocyte globuline) to better predict the immune-reconstitution (nessasary for optimal effect vaccines). 4 PostDocs, 5 PhD students and 3 technicians are working in my group. Current active funding: 4.5M (grants from ZonMW: cumm. 2.2M, Kika, Villa Joep, Ammodo, Vrienden UMC). I am an active member of various international working committees (e.g. EBMT, CIBMTR: chair of one of the CIBMTR working committees), a frequently invited speaker on international conferences and have over 100 peer-reviewed publications. In addition I am a member of a recently formed Westhafen Intercontinental group aiming to integrate/homogenize the EU and USA transplant and cell therapy practices and trying to come beyond phase I/II studies involving ATMPs (advanced therapy medicinal products) and is (co-)pi on various phase I/II with ATMPs. 100

101 NAAM: Marianne Boes, PhD X Laboratoriumhoofd Naam Centrum: UMC-Utrecht, Wilhelmina Kinderziekenhuis Naam Research groep: Boes lab Abstract I supervise a research laboratory that clarifies regulatory mechanisms in immune cells, particularly antigen presenting cells. The reason is that all adaptive immune responses are initiated by antigen presentation to antigen-specific T or B lymphocytes. We study dendritic cells for their potential to improve T or B lymphocyte-mediated immune therapy, and study efficacy of antibody-based interventions. Related, we study the genetic and cell biological origins of primary immune deficiency disorders to assign more targeted treatment. We here focus our research on disease mechanisms that cause inability of B lymphocytes to produce immunoglobulins, and causes of IL-1β-driven autoinflammatory diseases. Boes lab members and associates: 7 PhD students, 2 post-docs, 2 technicians. 101

102 NAAM: Ingrid Brok Promovendus Naam Centrum: RIMLS Naam Research groep: Tumor Immunology A transpantable tumor model to develop Immunocombination therapy of Neuroblastoma Authors: Brok I.C. 1, Kroesen M. 1,2, Wassink M. 1, Kers-Rebel E. 1, Reijnen D. 3, Boon L. 4, Hoogerbrugge P. 2,5, Adema G.J 1 Affiliations: 1. Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands. 2. Department of Pediatric Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands. 3. Central Animal Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands. 4. Bioceros B.V., Utrecht, The Netherlands. 5, Princes Máxima Center for Pediatric Oncology, The Bilt, The Netherlands. Still about half of the patients with advanced Neuroblastoma have a favorable outcome, despite multimodel treatments, including anti-gd2 monoclonal antibody immunotherapy. We believe this outcome could be improved with immunocombination strategies. To be able to test these approaches, we have developed two transplantable TH-MYCN models in C57Bl/6 mice and characterized its immunobiology. The cell line 9464D derived from autologous spontaneous TH- MYCN mice, expresses tumor antigen GD2 and low levels of MHC Class I and can be injected in a subcutaneous (SC) and orthotopic intra-adrenal (IA) setup. NK cells play an important role in tumor growth and analysis of the tumor infiltrating leukcoytes ex vivo revealed the presence of tumor associated myeloid cells and regulatory T cells. After intra-adrenal injection, tumor development was much more rapid than after subcutaneous injection. In the tumor microenvironment, lymphocyte and myeloid cell infiltration was equal. However, within the myeloid population, macrophages were more abundant and they expressed lower levels of MHC Class II, suggesting a more immune suppressive phenotype. We have stably transfected firefly luciferase in the 9464D cells and can now track tumor growth in time. Collectively we conclude that both the SC and IA transplantable TH-MYCN models are relevant models for the development of new immunocombination strategies for NBL patients, in which the IA model proves more stringent. Future experiments with these model will include immunotherapy combined with HDAC inhibitors. 102

103 NAAM: Astrid van Halteren Postdoc Naam Centrum: LUMC Naam Research groep: Immunologisch Laboratorium / HSCT unit WAKZ Langerhans cel histiocytose (LCH) is een zeldzame myeloïde neoplastische afwijking die zich zowel in kinderen als volwassenen kan presenteren. De ziekte wordt gekenmerkt door één of meerdere ophopingen van afwijkend gedifferentieerde myeloïde cellen (LCH-cellen) in bepaalde anatomische locaties. Zonder medisch ingrijpen kan het beloop van LCH variëren tussen de spontane genezing van een enkelvoudige ontstekingshaard tot uitbreiding naar een levensbedreigende systemische aandoening waarin ook milt, lever en beenmerg kunnen zijn aangedaan. In samenwerking met het AMC/EKZ (C. van den Bos), SKZ (A. Beekhuizen), Sick Kids Hospital Toronto (O. Abla) en Dana Farber Cancer Institute Boston (B. Rollins) onderzoeken wij nieuwe en reeds bekende somatische mutaties in relatie tot de klinische presentatie en het beloop van LCH na behandeling. Daarnaast richt ons onderzoek zich op het analyseren van de in de LCH laesie(s) aanwezige ontstekingscomponent, in het bijzonder de verschillende typen T lymfocyten. De hoofddoelen van dit onderzoek zijn 1) het vinden van een immuunsignatuur die, ten tijde van de manifestatie van de ziekte, patiënten met een laag risico op ziekte uitbreiding of reactivatie identificeert en 2) de ontwikkeling van een gecombineerd chemotherapie en immunotherapie protocol voor patiënten met een hoog risico op LCH reactivatie. Daarnaast proberen we i.s.m. SKION nieuwe tools te ontwikkelen die kunnen bijdragen aan een versneld LCH diagnosetraject en een betere monitoring van het ziektebeloop en response op therapie. 103

104 NAAM: Colin de Haar Postdoc Naam Centrum: UMC Utrecht Naam Research groep: Applied Tumor Immunology Abstract Over the last two years we have developed a cord blood dendritic cell (CBDC) vaccine derived from cord blood CD34+ hematopoietic stem cells. This CBDC vaccine will be loaded with WT1 antigen, over expressed 90% of the AML, and used as an immune therapy to prevent relapses in pediatric AML patients receiving cord blood transplantation. Patients will receive 3 biweekly vaccinations with WT1-loaded CBDCs starting 8-12 weeks post transplantation, and in addition to one-year relapse free survival also the induction of WT1-specific immunity will be assessed. We are currently translating our preclinical culture systems into a GMP vaccine production process at the Cell Therapy Facility at the UMC Utrecht. The specifics of the GMP CBDC production and final CBDC characteristics will all be part of the Investigational Medicinal Product Dossier (IMPD). We aim to start this phase 2A/B clinical trials early 2016 in both the UMC Utrecht and Great Ormond Street Hospital in London. 104

105 NAAM: Coco de Koning Promovendus Naam Centrum: UMC Utrecht Naam Research groep: Lab Boelens/Nierkens 105

106 NAAM: Charlotte van Kesteren Postdoc Naam Centrum: UMC Utrecht (Wilhelmina Kinderziekenhuis) Naam Research groep: Pediatric Blood and Marrow Transplantation Program, Boelens/Nierkens (U-DANCE / tumorimmunologie, LTI) Abstract Adequate drug dosing in children is a part of clinical drug development where still much is to be gained. Often, adult dosages are extrapolated to children applying scaling measures for body size. However, substantial variability in drug exposure as well as in clinical response to drugs are observed, indicating that improvement in drug dosing in children is highly needed. This is especially important for drugs with a narrow therapeutic window. An example of use of drugs with a narrow therapeutic index but with substantial variability is the conditioning platform in hematopoietic stem cell transplantation (HSCT) where cytostatic agents are applied. The polyclonal antibody ATG (Thymocyteglobulin) is part of this conditioning regimen to deplete circulating T-cells and to prevent Graft vs Host Disease (GVHD). Achieving the right exposure seems critical to ensure timely immune reconstitution post transplantation and to prevent occurrence of GVHD. The optimal dose in children was still unknown. In this project we have designed an optimal treatment regimen for ATG in HSCT optimizing clinical outcome for the individual pediatric patient. Hereto, a mechanism-based population pharmacokinetic-pharmacodynamic model capturing all features of ATG pharmacology was developed in order to understand, optimize and individualize treatment. In 2015, a prospective clinical study will be conducted to validate the developed dosing regimen. As a hospital pharmacist, I participate part-time in the project for daily supervision of the PhD student and implementing innovative techniques. Furthermore, new projects are initiated to further improve the conditioning platform in HCT in children, focusing e.g. on fludarabine. 106

107 Abstract Adequate immune-reconstitution (IR) after allogeneic hematopoietic (stem) cell transplantation (HCT) is of utmost importance, since most life threatening complications are associated with it: e.g. relapse, viral reactivation, graft-versus-host-disease, and transplant-related-mortality. Since the majority of studies only evaluated immune cells present in routine measurements (T-, B-, and NK-cells), starting at 3 months post-hct, little is known about the reconstituting immune system after HCT. More specifically, no information on early IR, immune cell subset-reconstitution, functionality, or the secretome (e.g. cytokines, chemokines in plasma/serum) is available. Therefore, the goal of my project is to provide a more detailed perspective on IR in pediatric patients after allo-hct, identifying robust predictors for clinical outcome. To this end, I am studying IR by evaluating PBMCs from a large cohort of pediatric allo-hct patients (N=165), starting follow-up as soon as 2 weeks post-hct. The presence and activation status and function of a wide variety of immune cell subsets will be analyzed using multi-color flow cytometry. The secretome during IR will be evaluated using Luminex on plasma samples from these patients. In addition, correlating leucocyte-reconstitution, cell function, and secretome with clinical outcome could lead to the identification of biomarkers for individual disease outcome, such as viral reactivity, GvHD, or relapse. Therefore, as these biomarkers are able to predict complications after HCT, this will aid in the path to precision medicine. In conclusion, this research will give in-depth insight into IR after allo-hct, and will identify factors affecting IR and survival. 107

108 NAAM: Stefan Nierkens Groepsleider Laboratoriumhoofd Naam Centrum: UMC Utrecht, Laboratory of Translational Immunology Naam Research groep: Boelens/Nierkens; U-DANCE Abstract The Boelens/Nierkens lab (the U-DANCE-project) develops (adjuvant) immuno-therapies to make hematopoietic stem cell transplantation safer and more effective in pediatric cancer patients. Our research focuses on 2 main aims: - Development of Dendritic-Cell vaccination strategies as an additional adjuvant therapy for refractory AML and Neuroblastoma. - Extensive immunomonitoring in clinical trails applying immunotherapy and hematopoietic cell (in particular cord blood) transplantation, including PK-PD. Immunomonitoring is developed in a specialized lab, U-DAIR, of the Laboratory of Translational Immunology (LTI; UMC Utrecht) 108

109 NAAM: Maud Plantinga Postdoc Naam Centrum: UMC Utrecht Naam Research groep: LTI, group Boelens/Nierkens Abstract Survival rates for childhood cancer have improved significantly over the last decade. However, only 50% of the children with acute myeloid leukemia (AML) survives, despite the last treatment option, allogeneic hematopoietic cell transplantation (allo-hct). Hence, there is a clear unmet need to improve survival chances with novel therapeutic-strategies. Immunotherapy seems particular attractive in the allo-sct setting as the newly developing immune system has great potential to induce long-lasting anti-tumor immunity. Dendritic cells (DCs) are professional antigen presenting cells that selectively instruct antigenspecific T-cells and could be applied after allo-sct as a synergistic multi-modal immunotherapy. Cord blood (CB) recently emerged as stem cell source for allo-hct. It is regulated that 1/5 of the CB-unit can be used for other purposes than HCT, providing me with the unique opportunity to generate CBDCs ex vivo from the same CB-unit as used for transplantation, to educate the reconstituting immune system after allo-hct in vivo. Recently, we developed a methodology to generate CBDCs for vaccination, which can be further engineered to excel in strong memory T-cell activation. I aim to select and modulate the most powerful CBDC subset for application as DCvaccine after allo-hct. More specifically, I will map and modify developmental pathways of specific DCs subsets in CB cultures. In addition, modulate the expression of inhibitory and stimulatory surface molecules and cytokine secretion by CBDCs. In conclusion, these experiments, utilizing state-of-the-art techniques, will lead to the development of a DC-vaccine, generating the required anti-tumor responses to improve survival rates in children with AML. 109

110 NAAM: Lotte Spel Promovendus Naam Centrum: UMC Utrecht Naam Research groep:laboratory of Translation Immunology Abstract INSIGHTS INTO NEUROBLASTOMA IMMUNOGENICITY TOWARDS IMMUNE-CELL BASED THERAPEUTIC INTERVENTIONS Lotte Spel, Dirk van der Steen, Nina Blokland, Max van Noesel, Mirjam Heemskerk, Jaap Jan Boelens, Marianne Boes, Stefan Nierkens. Merely 20% of high-risk neuroblastoma patients survive despite intensive treatment including chemotherapy, radiotherapy and surgery. Immunotherapy is considered a promising (adjuvant) treatment for neuroblastoma patients. Neuroblastoma cells are however poor immunogenic as they downregulate class I MHC expression, upregulate several natural killer (NK) inhibitory receptors and harbor only few immunogenic antigens thereby preventing their detection by NK cells and Cytotoxic T lymphocytes (CTL). We aim to develop a strategy to increase the immunogenicity of neuroblastoma cells. Using antigen-specific T cells we showed that the oncoprotein PRAME can be presented in MHC I molecules on neuroblastoma membranes and thus, serves as an immunogenic T cell antigen for neuroblastoma cells. PRAME-specific T cell activation was only observed when class I MHC levels were increased by either retroviral transduction of the HLA gene or stimulation with interferon-gamma (IFNγ). Because of the clinical toxic effects of IFNγ administration we sought for alternative routes to increase expression of PRAME peptide- MHCI complexes in neuroblastoma. We found that neuroblastoma cells upregulated class I MHC surface expression in response to NK cells, which recognize target cells by their lack of MHC I. The upregulation of MHC I subsequently stimulated the recognition of neuroblastoma cells by PRAME-specific T cells. This effect was contact-dependent and could be inhibited by IFNγ blocking antibodies. Altogether, we showed that immunogenicity of neuroblastoma is amenable and that NK cells can regulate MHC I levels on neuroblastoma cells which transforms them into CTL targets. 110

111 NAAM: Niek P. van Til Postdoc Naam Centrum: UMC Utrecht Naam Research groep: Boelens / Nierkens Abstract The only potentially curative treatment of (pediatric) acute myeloid leukemia (AML) patients, who are chemo-resistant, is hematopoietic cell transplantation (HCT). Unfortunately, these patients still have a poor prognosis with a high risk to relapse and poor survival-rates (~50%). A variety of advanced immune cell-therapies are being developed to eliminate residual AML-blasts after chemotherapy, such as a cord blood-derived dendritic cell-based (CBDC) vaccine to prime AML specific T cells. Additionally, T cell receptor (TCRs) or chimeric antigen receptor (CARs) gene-modified T cells can potentially eradicate AML-blasts by recognition through the human leukocyte antigen (HLA) system or extracellular proteins respectively. Clinical studies show that these cell-based therapies alone often only provide transient tumor regression or a risk of autoimmune dysregulation of engineered T cells. We aim to develop a combination of immune-therapies by genetically engineering cordblood dendritic cell vaccines to boost responses against AML antigens, by generating TCRs for a single chain TCR platform, and by constructing effective and safe chimeric antigen receptors. A currently developed CBDC vaccine ready for phase I/II implementation will be improved by overexpressing co-stimulatory pathways and eliminating co-inhibitory pathways by CRISPR/Cas9 technologies. In the future we aim to combine this with engineered T cells containing single chain TCRs or CARs. The strength of this approach lies in the combination of immunotherapies brought together into a single therapy that should lead to the complete elimination of remaining AML-blasts making it a potentially curative therapy for AML patients resulting in better survival chances for these patients. 111

112 LATE EFFECTS 112

113 NAAM: Marleen van den Berg X Postdoc Naam Centrum: VU medisch centrum Amsterdam Naam Research groep: Late effecten/ Kwaliteit van leven Abstract I am a post-doctoral researcher working at the department of Paediatric of Oncology- Haematology at the VU University medical Center Amsterdam, Netherlands. As an epidemiologist I am involved in conducting studies in the field of (long-term) effects after childhood cancer. Major research projects in which I am currently involved, include: Reproductive function, ovarian reserve, and premature menopause in female childhood cancer survivors (the DCOG LATER-VEVO study); Optimizing survivor participation in late effects studies by evaluating response rates, questionnaire mode preferences and satisfaction of Dutch childhood cancer survivors; Fertility Impairment in a pan-european cohort of female 5-year survivors of childhood cancerand (the PanCareLIFE study); Vincristine Induced Neuropathy in Children with Acute lymphoblastic leukemia (the VINCA study). 113

114 NAAM: Elvira van Dalen Postdoc Naam Centrum: Emma Kinderziekenhuis / Academisch Medisch Centrum Naam Research groep: Evidence Based Research & LATER Abstract In de kinderoncologie zijn veel wetenschappelijke onderzoeken gedaan. Voor professionals en patiënten is deze grote hoeveelheid informatie moeilijk bij te houden. Samenvattingen van kennis zijn dan ook noodzakelijk. De Cochrane Collaboration is een organisatie die deze samenvattingen, Cochrane systematische reviews, wereldwijd stimuleert en publiceert. In mijn rol als Coordinating/Methodological Editor van de Cochrane Childhood Cancer Group (CCG; een internationaal samenwerkingsverband van onderzoekers, hulpverleners en patiëntvertegenwoordigers op het gebied van diagnostiek en therapie voor kinderkanker, begeleid ik de review auteurs gedurende het gehele review proces. Inmiddels heeft de CCG veel kwalitatief hoogwaardige systematische reviews op het gebied van de kinderoncologie ontwikkeld en gepubliceerd. Een deel hiervan is ook al geupdate met bevindingen uit nieuwe onderzoeken, welke de conclusies van een review kunnen veranderen. Daarnaast heeft de CCG op verschillende manieren bijgedragen aan de promotie van evidence-based medicine in de kinderoncologie, o.a. door het geven van cursussen en presentaties, het ondersteunen van (internationale) richtlijnontwikkelingen en onderzoek op het gebied van systematische review methodologie. Voor de komende jaren hopen we steeds meer Cochrane systematische reviews op het gebied van de kinderoncologie te ontwikkelen en te updaten. Dit zal het gebruik van evidence-based behandelingen voor kinderen met kanker verder stimuleren en patiënten en ouders van kinderen met kanker zullen makkelijker relevante informatie kunnen vinden. Dit zal resulteren in een hogere kwaliteit van de zorg voor kinderen met kanker. Naast mijn werkzaamheden voor de CCG ben ik betrokken bij (internationale) studies op het gebied van cardiovasculaire toxiciteit van de behandeling van kinderkanker. 114

115 NAAM: Marloes van Dijk Promovendus Naam Centrum: VU Medisch Centrum Naam Research groep: Kinderoncologie / -hematologie Abstract Advances in cancer treatment during the last decades have led to improved survival of children and young adolescents with cancer, resulting in an increasing number of childhood cancer survivors (CCSs). However, many of these survivors suffer from late effects caused by their treatment, with fertility impairment as a primary concern among female CCSs. Despite a significant number of studies on female fertility following childhood and adolescent cancer, studies establishing precise estimates of treatment-related risk and effects of recently introduced agents are still lacking. Previous studies of fertility have been under-powered, biased, or based on self-report only without any hormonal assessments. Therefore, a pan-european cohort of over year female CCSs will be established. The overall aim of this study within PanCareLIFE is to generate evidencebased information concerning the risk factors and fertility status of childhood, adolescent and young adult female cancer survivors, on which evidence-based recommendations for counselling of these survivors will be developed. A cohort study will be performed using questionnaire data on fertility with a large number of subjects. Another sub-cohort of female survivors with serum samples will provide clinical information with levels of follicle stimulating hormone (FSH) and/or anti-mullerian hormone (AMH). A nested case-control study will evaluate the risk of impaired fertility assessed by questionnaire and/or hormone levels in great detail according to the type and intensity of treatment received. 115

116 NAAM: Irma van Dijk (SVP aankruisen wat van toepassing is) Postdoc (svp beschrijving research project) Naam Centrum: Academisch Medisch Centrum Naam Research groep: PhD Evidence based care research & LATER (Head: Leontien Kremer) Currently postdoc Radiotherapy AMC Abstract/Beschrijving eigen research project: (one example form the PhD projects) Radiation-associated cerebrovascular events in long-term childhood cancer survivors Background Improved childhood cancer survival is accompanied by an increased incidence of adverse events including cerebrovascular accidents (CVAs). Purpose We determined the incidence of symptomatic CVAs and assessed dose-effect relationships for cranial radiotherapy (CRT) and supradiaphragmatic radiotherapy (SDRT). Patients and Methods The cohort consisted of year survivors diagnosed between 1966 and CVAs were clinically confirmed, and graded for severity using the CTCAEv.3.0. We used Cox models to estimate the hazard ratio (HR) and 95% confidence interval (95%CI) for sex, age at diagnosis, brain surgery, chemotherapy, CRT and SDRT. In a second model, the relationship between CRT and SDRT radiation dose and the occurrence of a first CVA was assessed. Results After a median follow-up time of 24.9 years and at a median attained age of 31.2 years, 28 survivors had a first CVA. The 35-year cumulative hazard in survivors treated with CRT only was 14.2% (95%CI, %), 6.8% (95%CI, %) in survivors treated with SDRT only, and 24.3% (95%CI, %) in survivors who received both CRT and SDRT. Our analyses showed that both treatment locations significantly increased the risk of CVA in a dosedependent manner (HR CRT 1.02 Gy -1 ; 95%CI, , and HR SDRT 1.04 Gy -1 ; 95%CI, ). Conclusion Childhood cancer survivors treated with CRT and/or SDRT have an increased risk of CVA as compared with survivors who had no CRT and no SDRT. These radiation-associated CVAs occur at a very young age. Therefore, continuing follow-up with a focus on tailored preventive strategies to reduce the risk of CVAs in this young population deserves special attention. 116

117 NAAM: Lieke Feijen (SVP aankruisen wat van toepassing is) Promovendus (svp beschrijving research project) Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) Datamanager: Aslihan Mantici Abstract/Beschrijving eigen research project: Purpose To determine in a large cohort study of childhood cancer survivors (CCS) the incidence of and associated risk factors for validated symptomatic cardiac events (CEs), after childhood cancer treatment. Methods The DCOG LATER cohort includes 6,168 five-year CCS treated between 1/1/1963 and 12/31/2001 in one of the seven Dutch pediatric oncology/hematology centers before age 18 years. We identified CEs grade 3 or higher: heart failure, cardiac ischemia, pericarditis, valvular disease and arrhythmia (according to Common Terminology Criteria for Adverse Events) by questionnaires or by reviewing medical records. Reported CEs were subsequently validated with information from medical records. We used a competing risk analysis to calculate the cumulative incidence of the CEs, and a Cox regression model to evaluate potential risk factors. Preliminary results Thus far, we collected cardiac information of n=5,307 (86%) CCS. The overall cumulative incidence of the first occurring CE at the attained age of 40 years was 6.4% (95% Confidence Interval (CI) 5.3%-7.7%). Significant risk factors for the first occurring CE were treatment with doxorubicin (Hazard ratio (HR): 2.8; 95% CI ), epirubicin (HR: 2.1; 95% CI ), mitoxantrone (HR: 4.9; 95% CI ), cyclophosphamide (HR: 1.7; 95% CI ) and chest radiotherapy (HR: 2.4; 95% CI ). Conclusion CCS are at high risk of developing CEs, even at a young age. Especially after treatment with anthracyclines and/or chest radiation, and also after mitoxantrone or cyclophosphamide. Health care professionals need to consider these findings when treating new childhood cancer patients and during follow-up care of CCS. Summary promotietraject E.A.M. Feijen : Around 75% of childhood cancer survivors develop at least one health condition and 40% a severe or life-threatening health condition 17 years after the cancer diagnosis. Previous research has shown that an increase in health conditions among CCS translates into an increased risk of hospitalizations. This affects not only the physical health, but also has an effect on psychosocial aspects of the life of survivors. Cardiac events are one of the most 117

118 frequent health conditions in survivors contributing to significant morbidity and mortality. Cancer therapies like anthracyclines and irradiation directed at the chest have been associated with such cardiac events. The thesis is divided in two parts; Cardiac health problems and healthcare consumption and social outcomes in CCS. The general aims of part 1 creates optimal conditions for the evaluation of cardiac events in 5-year childhood cancer survivors, evaluation of the long term risk of cardiac events, and to uncover the associated (new) risk factors. To create optimal conditions for the evaluation, we first developed a new valid and consistent method for assessing the severity of cardiac events. For proper risk assessment we need to calculate the cumulative dose of anthracyclines, however there is uncertainty about whether the cardiotoxic effects of the different types of anthracyclines are comparable. We therefore assessed the ratio of cardiotoxicity of doxorubicin versus daunorubicin. Furthermore we evaluated the long term risk of cardiac events, and associated risk factors in a nationwide Dutch cohort of childhood cancer survivors and we describe the methodology of a large European project, the study on cardiac health problems within PanCareSurFup. Finally the general aims of part 2 are to evaluate healthcare consumption and social outcomes among 5-year childhood cancer survivors. We evaluated the hospitalization related health problems in survivors, by comparing them the general population. We also assessed risk factors for those health problems. Furthermore we compared survivors with the general population with respect to social outcomes. We evaluated if the survivors marry, work and live independently as much as their peers. 118

119 NAAM: Anna Font-Gonzalez (SVP aankruisen wat van toepassing is) Promovendus (svp beschrijving research project) Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) Health outcomes research Childhood cancer survivors (CCS) are at increased risk of adverse late effects including physical and social long-term effects of cancer and its treatment. We aimed to define the burden of adverse late effects in CCS by determining hospitalizations diagnosis and social outcomes compared to matched controls, and to define risk groups for hospitalization and unfavourable social outcomes that can benefit from interventions. We performed medical record linkage between a single-center cohort of five-year CCS and national registers. We retrieved hospitalization and social outcomes data from the CCS cohort and compared it to a random sample of the general Dutch population matched on age, gender and calendar year per CCS retrieved. Within CCS, we analyzed risk factors for hospitalization diagnosis and unfavorable social outcomes. PanCareLIFE guidelines on fertility preservation There is little uniformity in fertility preservation care for children with cancer. To ensure high-quality care, evidence-based clinical practice guidelines are essential. As a step towards guideline development, we aim to identify existing guidelines for fertility preservation in children and young adults with cancer, evaluate their quality, and explore differences in recommendations. We performed a systematic search in PubMed, guideline databases and websites of cancer, paediatric and fertility organizations. Two reviewers will evaluate the quality of the identified guidelines using the Appraisal of Guidelines Research and Evaluation Instrument (AGREE II). From the high quality guidelines, we will evaluate areas of concordance and discordance among the recommendations. Areas of discordance will be the base for formulating clinical questions for the future development of European-wide clinical practice guidelines. 119

120 NAAM: Gea Huizinga Postdoc Naam Centrum: Universitair Medisch Centrum Groningen (UMCG) Naam Research groep: School of Nursing and Health Afdeling Kinderoncologie/Hematologie Abstract Binnen de School of Nursing and Health en de afdeling Kinderoncologie/Hematologie van het UMCG ben ik werkzaam als senior onderzoeker (gezondheidswetenschapper). Ik doe (en begeleid) met name onderzoek naar korte- en lange termijn effecten van de behandeling van kanker bij kinderen. Binnen deze onderzoekslijn ben ik vooral betrokken bij kwaliteit van leven (QoL) gerelateerde studies. Voorbeelden van dergelijke studies zijn: QoL in relatie tot cardiotoxiciteit; sociale integratie en participatie bij survivors van een hersentumor en QoL van volwassen survivors van schildklierkanker op de kinderleeftijd. 120

121 NAAM: Ellen Kilsdonk (SVP aankruisen wat van toepassing is) Promovendus (svp beschrijving research project) Naam Centrum: AMC + VUmc Naam Research groep: AMC: Klinische Informatiekunde; VUmc: Kinderoncologie & hematologie AMC: Evidence based care research & LATER Abstract/Beschrijving eigen research project: Example of one of the studies: OVERALL AND CAUSE-SPECIFIC LATE MORTALITY IN CHILDHOOD CANCER SURVIVORS: A DCOG LATER COHORT STUDY Background Childhood cancer survivors face excess mortality decades after initial treatment. We aim to characterize late mortality among a cohort of Dutch survivors. Methods The DCOG LATER cohort includes 6,168 five-year childhood cancer survivors treated between 1/1/1963 and 12/31/2001 in one of the seven Dutch pediatric oncology/hematology centers before age 18. Vital status until 31th December 2013 was ascertained through hospital records and record linkage with municipal and other registries. Causes of death (92% complete) were obtained from medical records and uniformly coded according to the International Classification of Diseases, 10 th edition. Results The median follow-up of our cohort was 16.8 years from 5-year survival. In total, 621 out of 6168 survivors (10%) had died. Mortality was almost 13-fold increased compared to expected mortality rates for the Dutch population. Mortality was highest for survivors receiving radiotherapy and for survivors of Central Nervous System (CNS) and bone tumors. Preliminary analyses show cumulative mortality for specific causes of death 40 years post diagnosis distributed as follows: 6.6% primary childhood cancer, 5.3% secondary neoplasm, 1.2% cardiovascular, 0.8% respiratory, and 2.1% other causes. Discussion In this large cohort study, 10% of survivors died after reaching 5-year survival. Survivors treated with radiotherapy, and survivors of CNS and bone tumors had the highest cumulative mortality. During the first 20 years post diagnosis, primary childhood cancer dominated as cause of death, whereas other causes of death became increasingly important in very long term survivors. We are currently evaluating cause-specific mortality and risk factors in multivariate models. 121

122 Overview Thesis Ellen Kilsdonk (expected fall 2015) Project I Guideline-based clinical decision support for screening childhood cancer survivors on long term complications after treatment The Dutch Childhood Oncology Group Late Effects Group (DCOG LATER) has developed evidence-based guidelines for screening childhood cancer survivors (CCS) for possible long term complications of treatment. These paper-based guidelines appeared to not suit clinicians information retrieval strategies. In this study, we aim to create a Clinical Decision Support System suited to clinicians cognitive strategies in retrieving information. Project II - A nationwide questionnaire survey on late effects among Dutch childhood cancer survivors The DCOG LATER has initiated a nationwide study investigating late effects, the DCOG LATER study. As part of this retrospective cohort study, CCS will be asked to complete a general health and lifestyle questionnaire, to identify late effects not yet recognized and to define CCS groups at high risk for developing such late adverse effects. In such studies, high participation rates are crucial for the validity of the study results. However, participation rates in questionnaire studies have been declining over the past 30 years, mainly due to an increase in the proportion of subjects declining participation or not responding at all. In this study we examine the influence of web-based vs. paperbased questionnaires and follow-up strategies on participation rates of CCS. Project III Late mortality after childhood cancer Despite major advances in cure rates, CCS face excess mortality decades after initial treatment. In the first years recurrences predominate as cause of death, whereas the proportion of deaths from potential adverse late health effects seems to increase in very long-term survivors. The aim of this study was to characterize overall and cause-specific mortality among the DCOG LATER cohort. 122

123 NAAM: Judith Kok (SVP aankruisen wat van toepassing is) Promovendus (svp beschrijving research project) Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) 1e PI Cecile Ronckers Datamanager Christine Hoekstra Datamanager Anja van Eggermond Purpose To estimate organ-specific radiation exposure parameters for childhood cancer patients who had radiotherapy in the past and to apply these exposure parameters in dose-response analyses of established and suspected late health effects of radiotherapy. Summarized description of project RADIATION EXPOSURE CHARACTERIZATION FOR LATE EFFECTS RESEARCH: THE DCOG- LATER APPROACH Background Radiotherapy (RT) is a life-saving anti-cancer treatment but can cause health problems in (childhood) cancer survivors (CCS). To date, most epidemiologic CCS studies on RT effects are nested case-control studies, using absorbed dose to a specific point in an organ as the RT-exposure metric of interest. The resulting radiation dose-response curves provided valuable insights, but, are typically insufficient to incorporate in highly sophisticated modern radiotherapy planning. Moreover, translation into evidence-based follow-up guidelines can be challenging. To take the next step, we focus on cohort-based radiation dosimetry. Methods/Results The DCOG-LATER cohort includes 6,168 five-year CCS diagnosed between 1963 and 2002, of whom approximately 2200 had RT. Details on prescribed radiotherapy treatment were collected from the radiation oncologist letter. To enable reconstruction of the absorbed organ doses and exposed organ volume parameters from typical cancer treatments we collect RT-records and simulation films (65% retrieved to date, ongoing). Since individual dosimetry is very time consuming, we are constructing a radiation exposure matrix. Survivors will be assigned to a matrix-subgroup defined by patient characteristics and RT treatment details. Organ-specific RT doses and exposed organ volumes will be reconstructed for one representative survivor per matrix-subgroup using established methods (1). These measures are then assigned to the entire subgroup. Using these established dose reconstruction methods will allow for comparability with published research and for future international pooling. Conclusions The DCOG-LATER Research Program will allow us to learn from the past to generate clinically-relevant measures of RT dose response relationships. Reference 1. Stovall M. et al Radiat Res; 166:

124 NAAM: Leontien Kremer Functie categorie Group leader, pediatrician, methodologist Naam Centrum: Emma Kinderziekenhuis/Academisch Medisch Centrum Naam Research groep: Evidence based care research & LATER Abstract: I am trained as a paediatrician and I studied clinical epidemiology. I am passionate to initiate and execute innovative and collaborative projects. I am active in local, nationwide and international groups and projects in: Evidence based care research: systematic reviews, clinical guidelines, health outcomes LATER: survivorship research Currently I am active as a: 1. Research leader of the EKZ/AMC research group: Evidence based care research & LATER, including: Cochrane Childhood Cancer Group; focusing on the development of summaries of knowledge for treatment of childhood cancer (Cochrane systematic reviews) with a Editorial base (Elvira van Dalen, 1 vacancy, Edith Leclerq, Jos Noorman) Quality of care research: Dunja Dreesens PhD (Maastricht/Amsterdam), Rutger Knops PhD LATER health outcome research: Lieke Feijen, PhD, Nina Streefkerk PhD, Ellen Kilsdonk PhD (AMC, VUMC, NKI) Guideline research: Renée Mulder postdoc, Anna Font Gonzalez PhD: Erik Loeffen PhD (Groningen and Amsterdam) LATER survivorship research health outcomes Lieke Feijen, PhD, Nina Streefkerk PhD, Ellen Kilsdonk PhD (AMC, VUMC, NKI), Helena van der Pal, Research assistants: slihan Mantici Jeanette van Gelder LATER Radiation and adverse effects: Cécile Ronckers leader: Judith Kok PhD Jop Teepen PhD, Irma van Dijk postdoc, Research assistants: Christien Hoekstra, Anja Eggermond LATER Endocrine late effects: Hanneke van Santen (WKZ) leader: Sarah Clement PhD 2. Chair of the national DCOG LATER group; focusing on guidelines and research for survivors 3. Participant / Workpackage leader in EU projects: PanCare SurFup, PanCareLIFE, PROCARDIO 4. Chair of the International Guideline Harmonization Group, Co chair: Melissa Hudson, St Jude 5. Chair of the guideline committee of the Dutch Paediatric Society 124

125 NAAM: Renée Mulder (SVP aankruisen wat van toepassing is) Postdoc (svp beschrijving research project) Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) Theme: Evidence based guidelines in pediatric oncology International Late Effects of Childhood Cancer Guideline Harmonization Group Clinical practice guidelines addressing late effects surveillance for long-term survivors of childhood, adolescent, and young adult (CAYA) cancer have been independently developed by several cooperative groups and institutions. Following recognition that this nonintegrated approach of guideline development resulted in duplication of work and inefficient use of resources, the International Late Effects of Childhood Cancer Guideline Harmonization Group (IGHG) was initiated in 2010 with the aim of establishing a common vision and integrated strategy for the surveillance of late effects in CAYA cancer survivors. The IGHG is directed by a multidisciplinary core group including healthcare professionals, content experts, researchers and methodologists with skills in evidence appraisal and synthesis. The strategy used by the IGHG involves evidence-based methods. For each exposure-based surveillance recommendation considered, the IGHG organizes a working group comprised of individuals with specific topic expertise to evaluate concordances and discordances among existing guidelines and evaluation of the supporting evidence. The working group organizes extensive evidence summaries to facilitate the formulation of recommendations. The quality of evidence and the strength of recommendations is determined using an adapted version of the American Heart Association s Applying Classification of Recommendations and Level of Evidence. The IGHG first focused on harmonizing recommendations for secondary breast cancer and cardiomyopathy surveillance. In collaboration with the PanCareSurfUp Consortium the IGHG is now harmonizing recommendations for male and female gonadotoxicity, and secondary thyroid and CNS neoplasms. With the initiation of this endeavor the IGHG aims to optimize collaboration in guideline development to improve the quality of care for CAYA cancer survivors. 125

126 NAAM: Aleid van Noortwijk Promovendus/ MD Naam Centrum: Erasmus MC Sophia Kinderziekenhuis & Prinses Maxima Centrum, ism Pancare LIFE, DCOG Later en VEVO studie Naam Research groep: Toxicity Begeleiders: Dr. M.M. van den Heuvel-Eibrink & prof. Dr. J. Laven Research interesses/expertises Endocriene late effecten na kinderkanker, Fertiliteit, Kindergynaecologie Abstract: Eén van de belangrijke late effecten van kinderkanker is gonadale dysfunctie. Het is bekend dat alkylerende middelen en abdominale radiotherapie gonadale dysfunctie kunnen veroorzaken. Ons onderzoek richt zich op het identificeren van andere determinanten. We hebben de invloed van genetische variatie op gonadale functie in volwassen vrouwelijke CCS onderzocht en vonden dat genetische variatie geassocieerd met jongere menopauzeleeftijd in de algemene populatie, geassocieerd is met een verminderde gonadale reserve in CCS, onafhankelijk van therapie. In onze recente studies leverden relevante determinanten op van verminderde gonadale functie gevonden, wederom onafhankelijk van therapie. Meisjes met kanker bleken lagere AMH waarden bij diagnose hadden, wat geassocieerd bleek met de algemene gezondheidstoestand. Ook werd gonadale functie op lange termijn bij mannelijke CCS onderzocht. Op basis van longitudinale data lijkt herstel mogelijk te zijn, met uitzondering van CCS die al een erg beperkte gonadale functie hebben. Met dit project willen wij meer kennis opdoen over de invloed van andere factoren dan chemotherapie en radiotherapie op de gonadale functie om patiënten in de toekomst beter te kunnen counselen over de mogelijke gevolgen van de behandeling.speciale aandacht daarbij krijgt genetische variatie, met support van EU FP7 PCL project 126

127 NAAM: Heleen van der Pal Postdoc (svp beschrijving research project) Internist/hoofd van de volwassen LATER-polikliniek EKZ/AMC Naam Centrum: Emma Kinderziekenhuis/Academisch Medisch Centrum Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) THEME: Late effects after treatment for childhood cancer: Development of new knowledge about all late effects after treatment for childhood cancer Deliver and develop optimal patient care, follow-up and guidelines for childhood cancer survivors (including screening and coordination of complex care) Transition of care for childhood cancer survivors from paediatric to adult services Initiate, facilitate and stimulate multidisciplinary collaboration across Europe via the PanCare network to set up excellent, clinically meaningful late effects research Abstract/Beschrijving eigen research project (max. 250 woorden): (voor promovendi, postdocs, klinische research fellow, klinisch projectleider) The main theme of my research project is to initiate, participate, coordinate and facilitate research regarding all late effects of treatment for childhood cancer, especially within our own institute (EKZ/AMC) but also in collaboration within Europe (PanCare network) and worldwide (International Guideline Harmonization Group). Within the DCOG LATER group and the DCOG LATER Study, I am responsible for several subprojects. The nationwide DCOG LATER study aims to identify treatment related and/or genetic predictors and screening tests leading to early detection of late effects in order to adjust future evidence-based recommendations for surveillance, improve future treatment protocols, and identify adequate interventions for late effects. I am the PI for the subproject on social outcomes, which aims to examine the long-term social outcomes of adult survivors of childhood cancer compared to a healthy sibling control population in terms of education, academic achievement, employment, occupation, social benefits and insurance issues. I am co-pi on the study aiming to assess the prevalence and risk factors of hypothyroidism and hyperthyroidism in the entire cohort of childhood cancer survivors. Furthermore, I am co-pi on the subprojects on second primary malignancies with the focus on breast cancer and on long-term renal effects after childhood cancer. For the transition of care and international guideline development, I am one of the DCOG LATER representatives in the EU-FP7 (Workpackage 6) funded PanCareSurFup collaborative study. In the development of guidelines currently my main focus is on cardiomyopathy surveillance, transition of care and second primary central nervous system tumours. 127

128 NAAM: Cécile Ronckers (SVP aankruisen wat van toepassing is) Postdoc (svp beschrijving research project) Project leadder researchline late effects of pediatric radiotherapy Naam Centrum: Emma Kinderziekenhuis/Academisch Medisch Centrum Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) THEME: late effects of pediatric radiotherapy: Radiation dosimetry Second tumors and radiation-related normal tissue damage Quantitative assessment of radiation dose response and its modifiers to address both etiologic and clinically-relevant research questions Initiate, facilitate, and stimulate multidisciplinary collaboration across radiation sciences to set up excellent, clinically meaningful late effects research Abstract/Beschrijving eigen research project (max. 250 woorden): I lead two PhD project within the DCOG LATER collaborative group: the DCOG LATER dosimetry project (PhD student J.Kok) and the second cancer project (PhD student J.Teepen, funding KWF) and am one of the PI s for the project on mortality and cause of death evaluation in the DCOG-LATER cohort (PhD student E.Kilsdonk) and I am one of the DCOG LATER representatives in the EU-FP7 funded PanCareSurfup collaborative study (local PI: Kremer). I collaborate with I. van Dijk who introduced radiobiologic measures of exposure in late effects research and on a Cochrane systematic review and meta-analysis of radiotherapy-related breast cancer. I aim to initiate further retrospective studies on breast cancer and on normal tissue damage in the DCOG LATER cohort (thyroid disease with H van Santen), cataract, and pulmonary damage) and am involved in a recently funded KIKA Program (PI: T. Alderliesten, Dept of RT) to develop a novel dosimetry method (2D-3D) to increase the clinical application of our late effects results. Also together with L. Kremer and G Janssens I wrote a grant proposal to study side effects of 3D-planned pediatric RT in the period in a national cohort with contributions from many different disciplines (KWF, under review). Finally I contribute as expert to several international review and guideline groups in the area of late effects of radiotherapy (PENTEC,, IGHG,, ICRP, EU-PCSF, EU-ENCCA Passport), and aim to spearhead/be involved in future initiatives for proper prospective RT registration nationally and internationally. 128

129 NAAM: Nina Streefkerk Promovendus Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) Long term morbidity and healthcare consumption in childhood cancer survivors: the DCOG LATER national linkage study Background Over the past decades, survival rates for children with cancer have substantially improved. However, childhood cancer survivors (CCS) are at risk of developing chronic health conditions, among which are organ dysfunction and second neoplasms. Little is known about the overall burden of long-term morbidity in CCS and how that translates to health care consumption. Purpose To perform a comprehensive assessment of the extent of long term morbidity, health care consumption and associated risk factors in a nationwide cohort of CCS. Methods Our study population is the DCOG LATER (Dutch Childhood Oncology Group) cohort that includes 6,168 5-year CCS treated in one of the 7 Dutch oncology centers between 1963 and Firstly, we will use DCOG questionnaires, validated with medical records, to quantify the prevalence, severity and risk factors of health conditions among CCS compared to a sibling control group. Secondly, we will perform record linkage between the DCOG LATER cohort and the Dutch Hospital Discharge Register. We will use longitudinal analyses to evaluate hospitalizations, related health conditions and associated risk factors among CCS compared to the general population. Thirdly, we will perform record linkage with the NIVEL Primary Care Database to evaluate the number and type of health conditions presented at general practice consultation in CCS compared to control patients. Conclusion Different data sources will be used to provide a comprehensive overview of long-term morbidity and health care consumption in CCS and define risk factors. Understanding this is essential to provide CCS the optimal patient centered follow-up care. 129

130 NAAM: Jop Teepen (SVP aankruisen wat van toepassing is) Promovendus (svp beschrijving research project) Naam Centrum: Academical Medical Center / Emma Children s Hospital Naam Research groep: Evidence based care research & LATER (Head: Leontien Kremer) 1 E P.I. s Cecile Ronckers Datamanager: Aslian Mantici LONG-TERM RISK OF SECOND MALIGNANT NEOPLASMS AMONG CHILDHOOD CANCER SURVIVORS: A DCOG LATER COHORT STUDY Purpose To analyze the long-term risk of second malignant neoplasms (SMNs) in a large cohort of 5- year survivors of childhood cancer and quantify the contribution of associated treatmentrelated risk factors. Summarized description of project The DCOG LATER cohort includes 6,168 five-year childhood cancer survivors treated between 1/1/1963 and 12/31/2001 in one of the seven Dutch pediatric oncology/hematology centers before age 18. Detailed information on prior cancer diagnosis and treatment were collected, including information on radiotherapy dose, field, and fractionation schedule and chemotherapy dose per drug. SMNs were identified by linkage with the population-based Netherlands Cancer Registry ( ), and by clinical information from the pediatric oncology medical charts and from the late effects outpatient clinic; additional linkage with the Dutch Pathology Registry ( ) is ongoing. The incidence of SMNs (excluding basal cell carcinoma) was compared with age-, sex-, and calendar year-specific expected incidence numbers from the Dutch general population by calculating standardized incidence ratios (SIRs) and absolute excess risks (AERs) per 10,000 person-years. We are currently evaluating cumulative incidence of SMNs and the effects of potential risk factors for SMNs in multivariable risk models. Preliminary results The median follow-up from diagnosis of our cohort was 20.7 years (20% >30 y). So far, we observed 245 SMNs during 103,969 person-years of follow-up vs expected (SIR=4.7; AER=18.6/10,000 person-years). The most frequently occurring SMNs are breast cancer (n=40; SIR=4.7), thyroid cancer (n=24; SIR=15.9), and central nervous system tumors (n=22; SIR=8.5). Results of analyses of cumulative incidence and multivariable risk models will also be presented during the meeting. 130

131 PHASE I-II STUDIES 131

132 NAAM: Robin Kloos Promovendus Naam Centrum: Erasmus MC-Sophia Kinderziekenhuis Naam Research groep: Asparaginase/ALL (dr. Inge van der Sluis) Abstract Optimization and individualization of asparaginase treatment in children with acute lymphoblastic leukemia. Introduction: Asparaginase is an essential component of therapy of acute lymphoblastic leukemia in children. However, allergy and silent inactivation (neutralization in absence of clinical signs) hampers its efficacy. Therapeutic drug monitoring (TDM) is now used in the DCOG ALL-11 protocol to individualize the dosages based on activity levels. Besides, a randomized study is being performed to determine if a continuous dosing schedule leads to less hypersensitivity. Objectives/methods: This project consists of several studies, all part of the TDM or randomization study in the ALL-11 protocol. The main objective is to develop an optimal individualized asparaginase treatment protocol. Toxicity: Toxicity in the non-continuous schedule will be compared to both the continuous and the ALL-10 fixed dosing schedule. This toxicity includes allergy, thrombosis, pancreatitis, central neurotoxicity, increased liver enzymes, dyslipidemia and hyperglycemia. Pharmacokinetics: Asparaginase pharmacokinetics will be studied since right now, TDM is only based on trough levels. After measuring extra activity levels, a NONMEM analysis will be performed using anti-asparaginase antibody formation, treatment phase, comedication and others as covariates. Methotrexate: Patients in the continuous arm are treated with asparaginase and high dose methotrexate concomitantly, possibly causing differences in toxicity and efficacy of methotrexate. Polyglutamylation of methotrexate in erythrocytes will be measured in patients with and without concomitant asparaginase therapy. Overlapping toxicity will be compared as well. Costs: A cost-analysis of TDM of asparaginase in ALL-11 will be performed and compared to the costs of the ALL-10 fixed dosing schedule. 132

133 NAAM: Sebastiaan D.T. Sassen Promovendus Naam Centrum: Erasmus MC - Sophia Naam Research groep: Abstract Towards evidence-based use of ciprofloxacin prophylaxis and glucocorticoids for children with cancer This is a multicenter study focusing on the pharmacokinetics and -dynamics of predniso(lo)ne, dexamethasone and ciprofloxacin in pediatric patients with acute lymphoblastic leukemia (ALL). Currently the dose of the medication is adjusted for body weight or body surface area of the patients. This is however not optimal. Over a tenfold difference in plasma levels between patients has been observed. Hence some patients (e.g. younger patients) have a lower exposure compared to others and might receive suboptimal treatment. High levels on the other hand might lead to toxicities. The aim of this study is to develop individualized therapy. By studying the pharmacokinetics we will determine which factors affect the plasma concentration (e.g. kidney function, age, BMI, formulation, comedication, etc) and build a model to calculate the individual doses according to the patient characteristics. In addition the pharmacodynamics are studied to provide information concerning the optimal plasma concentration by correlating the plasma levels to outcome, for example the mean residual disease for the glucocorticoids and the number of gram negative infections during ciprofloxacin prophylaxis. NONlinear Mixed-Effect Modeling (NONMEM) is utilized for the population pharmacokinetic modeling. In addition the long term safety of ciprofloxacin prophylaxis on cartilage is studied utilizing 3 Tesla MRI. This study is another step in the direction of optimal individualized therapy for children with ALL. 133

134 NAAM: Natasha van Eijkelenburg Promovendus Naam Centrum: Prinses Maxima Centrum voor kinderoncologie Naam Research groep: DCOG-Early Clinical Trial Consortium (DCOG-ECTC) Abstract Titel: vroege fase geneesmiddelen onderzoek in de kinderoncologie Many drugs in pediatric oncology are used despite the fact that the drugs are not specifically labeled or licensed for use in pediatric indications. The Dutch medicine law restricts the use of off-label and unlicensed drugs, and requires that additional studies are performed to provide the evidence where this is lacking. Over the past few years, as a result of the current revolution in molecular biology, many new potential treatment targets have been discovered and hence many new drugs have been developed. The next challenge is to evaluate these drugs not only in adults, but also in children with cancer. Pediatric studies are essential as there may be differences in pharmacokinetics, safety and efficacy between children and adults. In this research project Natasha van Eijkelenburg evaluates new drugs and expands the knowledge on existing drugs in children with cancer. Firstly, the safety and efficacy of gemcitabine in addition to 131 I-MIBG therapy is evaluated in pediatric relapsed neuroblastoma patients. This mulitnational phase II study is currently enrolling patients in the Netherlands and Germany and uptill now 12 patients have been treated. Second, following a new dosing guideline for Vancomycine, pharmacokinetics of this drug is evaluated prospectively throughout all pediatric oncology patients in 2 sites. Besides these prospective clinical trials, 2 systematic reviews are performed: 1 on skeletal related events and 1 regarding target dependence in tumor specific context and targeted therapy. 134

135 NAAM: Inge van der Sluis Klinisch-projectleider Naam Centrum: ErasmusMC-Sophia Children s Hospital Naam Research groep: early clinical trials asparaginase/all Abstract Efficacy, drug resistance and toxicity of extensive use of asparaginase in childhood acute lymphoblastic leukemia (PhD-project W Tong, co-promotor IM van der Sluis) 1. Pharmacokinetics and pharmacodynamics of PEGasparaginase and Erwinia asparaginase in the DCOG ALL11 protocol: towards improved therapeutic drug monitoring. (PhDproject R Kloos, co-promotor IM van der Sluis) 2. Therapeutic drug monitoring (TDM) of asparaginase and randomized PEGasparaginase study in the DCOG-ALL11 protocol 3. Pharmaco-economic analysis of asparaginase therapy and TDM 4. Recombinant asparaginase in ALL 5. Participating as (principal/coordinating/sub-) investigator in early clinical trials, e.g.: - Clofarabine, daunoxome and cytarabine in AML (phase I/II). - Bortezomib in ALL (phase II). - PKC412 in relapsed/refractory leukemia. (phase I/II). - Gemcitabine/MIBG therapy in neuroblastoma (phase II). - NECTAR: Nelarabine, Etoposide and Cyclophosphamide in T-ALL (phase I). - Dasatinib in Ph+ Leukemia with Resistance/Intolerance to Imatinib (phase II) - Posaconazole in children with neutropenia (phase IB). - Blinatumomab in BCP-ALL (phase II). - LDK378 in malignancies with a genetic alteration in anaplastic lymphoma kinase (ALK) (phase I). - nilotinib in newly diagnosed Ph+ CML in chronic phase (CP) or with Ph+ CML in CP or accelerated phase (AP) resistant or intolerant to imatinib or dasatinib (phase II). - bevacizumab in high-grade glioma (phase II). - Vincristine/irinotecan with or without temozolomide in rhabdomyosarcoma (phase II). - VINILO: Vinblastine and nilotinib in low-grade glioma (phase I/II). - DACOGEN: (decitabin and cytarabine) in AML (ph I-II) - Volasertib in acute leukemias (ph I-II) - Carfilzomib in ALL (ph I-II) 135

136 NAAM: Dr. C.M. Zwaan (SVP aankruisen wat van toepassing is) Centrumhoofd Naam Centrum: Erasmus MC Sophia kinderziekenhuis, kinderoncologie/hematologie Naam Research groep: New Agents 136

137 ONCOGENOMICS 137

138 NAAM: Marjolijn Jongmans Postdoc Naam Centrum: Naam Research groep: Radboudumc Tumor Genetics Nijmegen Beschrijving eigen research project: It has been estimated that up to 10% of all childhood malignancies result from a genetic predisposition. This figure likely represents an underestimation since it is primarily based on patients with a recognizable clinical syndrome or a positive family history for cancer. With recent rapid technological developments in next generation sequencing (NGS), including whole exome sequencing, the identification of cancer predisposing genes in single patients has become a reality, thus providing enormous challenges as well as opportunities for patient care. We (this is a joint project with Esmé Waanders) apply whole exome sequencing on germline DNA of children, and their parents, with cancer and at least one of these features: intellectual disability, congenital anomalies, adult type of cancer, a family history for childhood cancer or multiple primary malignancies. All cases remained undiagnosed after consultation by a clinical geneticist and often multiple genetic tests. Analysis of the first 15 patients resulted in a high yield of causative mutations. Three patients carried mutations in the well-known cancer genes TP53 and DICER1 (n=2). In three other children, exome sequencing revealed syndromes that possibly contributed to their malignancy (EP300 based Rubinstein Taybi syndrome in a girl with acute myeloid leukemia; ARID1A based Coffin Siris syndrome and ACTB based Baraitser Winter syndrome in boys with acute lymphatic leukemia (ALL)). In addition, we identified novel candidate genes for which we are currently exploring their role in childhood cancer predisposition We expect that this research will result in an improved characterization of hereditary forms of childhood cancer, which will facilitate decision making on surveillance of patients and relatives and, in addition, may reveal new targets for treatment. 138

139 NAAM: Irsan Kooi Promovendus Naam Centrum: VU medisch centrum Naam Research groep: Department of clinical genetics, section oncogenetics Description of our work: Our multidisciplinary research team consisting of molecular biologists, bio-informaticians and clinicians works on the improvement of treatment and diagnosis of retinoblastoma (RB). By integrating innovative high-throughput genomics, transcriptomics and methylomics data with clinical, histo-pathological, radiological, and (functional) laboratorial determinations we try to learn about RB carcinogenesis and translate gained knowledge to improved care for RB patients. To obtain a comprehensive view, we analyze our results on human RB with results obtained from murine RB mouse models and available highdimensional published data. In parallel, we try to develop a fast, sensitive and specific genetic diagnosis for hereditary RB. Using multiple DNA amplification strategies (long-range PCR and innovative target locus amplification) followed by ultra-deep next-genereation sequencing we try to cover the detection of (low mosaic, splice-site and deep-intronic) mutations, exonic deletions and whole gene deletions in a single assay. Ultimately, this would allow for fast and cost-efficient genetic diagnosis that enables genetic diagnosis-based treatment decisions. Description of our team: Irsan E. Kooi a,e, Berber M. Mol a, Annette C. Moll b, Paul van der Valk c, Marcus C. de Jong d, Pim de Graaf d, Antoinette Y.N. Schouten- van Meeteren e, Hanne Meijers-Heijboer a, Gertjan J.L. Kaspers f, Hein te Riele a,g, Jacqueline Cloos f,h, Josephine C. Dorsman a a Department of Clinical Genetics, b Department of Ophthalmology, b Department of Pathology, d Department of Radiology and Nuclear Medicine, f Department of Pediatric Oncology/Hematology, h Department of Hematology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands. e Department of Pediatric Oncology, Emma Children s Hospital, Academic Medical Center (AMC), Postbus 22660, 1100 DD, Amsterdam, The Netherlands. g Division of Biological Stress Response, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands. 139

140 NAAM: Roland Kuiper Groepsleider Naam Centrum:Radboudumc, Nijmegen Naam Research groep:cancer Genomics Abstract The ultimate aim of my group is to perform genomic characterization of acute lymphoblastic leukemia in order to improve diagnosis, provide novel options for (targeted) therapy and recognize patients at risk for developing cancer. We are focusing on i) the multiclonal evolution of BCP-ALL and its role in therapy resistance, ii) the genetic characterization of relapsed BCP-ALL, iii) the role of genetic predisposition in childhood cancer, including ALL, and iv) the development and implementation of novel diagnostic procedures for genetic characterization of childhood ALL. 140

141 NAAM: Maroeska te Loo Klinisch-projectleider Naam Centrum:Radboudumc Naam Research groep: Pediatric Oncology Pharmacogenetics in pediatric cancer Abstract Pharmacogenetics of treatment response in patients with osteosarcoma Osteosarcoma is the most common bone tumor in children and adolescents. Despite multiagent chemotherapeutic treatment, osteosarcoma patients relapse frequently and survival has reached a plateau in the past decades. Additionally, survivors often experience long-term chemotherapy-induced toxicities. A poor response to chemotherapy seems to be the predominant risk factor for an unfavorable outcome. Pharmacogenomic research may provide more insight into the mechanisms underlying drug response and could offer risk stratification at diagnosis and optimize outcome. We have previously identified several genetic polymorphisms in genes in the metabolic pathways of cisplatin and doxorubicin which might be used for risk stratification of patients in relation to treatment response. However, the complex metabolism of the drugs used in osteosarcoma treatment involves a broader range of drug metabolic enzymes and transporters. Therefore we have performed large scale screening of 1,936 genetic variants in 231 genes known to be involved in drug metabolism and transport. Germline DNA from 310 pediatric and adult osteosarcoma patients treated in the Netherlands was genotyped using the Drug Metabolizing Enzymes and Transporters array. Associations between genetic variants and histological response to preoperative chemotherapy as well as ototoxicity were assessed using logistic regression models. Associations between genetic variations and Disease Free Survival were evaluated using Cox proportional hazards models. Results from these pharmacogenomic analyses may help to identify patients at risk of a poor response or toxicities. Upon validation in functional studies and in larger prospective studies, pharmacogenetic markers could eventually enable risk stratification at diagnosis and thereby improve treatment for osteosarcoma patients. 141

142 NAAM: Simon van Reijmersdal Research technician Naam Centrum:Radboudumc, Nijmegen Naam Research groep:cancer Genomics (PI Roland Kuiper) Abstract Tasks within the Cancer Genomics group: 1. development of Targeted Locus Amplification (TLA) as a novel single-test detection method for a diverse repertoire of gene fusions, deletions and mutations in childhood ALL. 2. technical support on running projects (genomic profiling and data analysis). 3. IT support department of Human Genetics Nijmegen. 142

143 NAAM: Hanneke Vos Promovendus Naam Centrum: Radboudumc Naam Research groep: Pediatric Oncology Pharmacogenetics in pediatric cancer Abstract Pharmacogenetics of treatment response in patients with osteosarcoma Osteosarcoma is the most common bone tumor in children and adolescents. Despite multiagent chemotherapeutic treatment, osteosarcoma patients relapse frequently and survival has reached a plateau in the past decades. Additionally, survivors often experience long-term chemotherapy-induced toxicities. A poor response to chemotherapy seems to be the predominant risk factor for an unfavorable outcome. Pharmacogenomic research may provide more insight into the mechanisms underlying drug response and could offer risk stratification at diagnosis and optimize outcome. We have previously identified several genetic polymorphisms in genes in the metabolic pathways of cisplatin and doxorubicin which might be used for risk stratification of patients in relation to treatment response. However, the complex metabolism of the drugs used in osteosarcoma treatment involves a broader range of drug metabolic enzymes and transporters. Therefore we have performed large scale screening of 1,936 genetic variants in 231 genes known to be involved in drug metabolism and transport. Germline DNA from 310 pediatric and adult osteosarcoma patients treated in the Netherlands was genotyped using the Drug Metabolizing Enzymes and Transporters array. Associations between genetic variants and histological response to preoperative chemotherapy as well as ototoxicity were assessed using logistic regression models. Associations between genetic variations and Disease Free Survival were evaluated using Cox proportional hazards models. Results from these pharmacogenomic analyses may help to identify patients at risk of a poor response or toxicities. Upon validation in functional studies and in larger prospective studies, pharmacogenetic markers could eventually enable risk stratification at diagnosis and thereby improve treatment for osteosarcoma patients. 143

144 NAAM: Esmé Waanders Postdoc Naam Centrum: Radboudumc Naam Research groep: Cancer Genomics (PI Roland Kuiper) Abstract Due to increased treatment efficacy, more children than ever survive their primary malignancy. Inherently, germline predisposing variants will accrue in the population. It is my aim to identify and study these predisposing variants to improve our understanding of the cause, incidence, and mechanism of cancer development, which will subsequently have consequences for its clinical management. I use state-of-the-art genome wide profiling techniques to analyze aberrations in germline and tumor tissues of carefully selected and phenotyped patients. These include patients with two successive malignancies, patients with co-morbidities (intellectual disability, congenital anomalies), and patients with affected family members, mainly focusing on pediatric acute lymphoblastic leukemia (ALL), lymphoma and osteosarcoma. Sequencing of parent-child trios allows the identification of recessively inherited and de novo variants. Sequencing of tumor and germline samples facilitates the association of germline variants with oncogenic pathways. Candidate gene functions are assessed in cell model systems. A KWF-fellowship enabled me to work with Charles Mullighan at St. Jude Children s Research Hospital. There, I found a germline PAX5 mutation in two families with recurrent B-lineage ALL (Nat Genet 2013) and I study clonal evolution of relapse development. In patients with two fully discordant successive leukemia occurrences, I identified several predisposing aberrations (J Clin Oncol 2011). The trio approach revealed variants in well-known cancer genes (TP53, DICER), in genes associated with known syndromes (EP300, ARID1A) and novel candidate genes. These preliminary data indicate that rare germline aberrations are more frequently found than previously anticipated, which will be of significant clinical importance. 144

145 SUPPORTIVE CARE 145

146 NAAM: Aeltsje Brinksma Postdoc Naam Centrum:UMCG Naam Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract One of the themes of our research group focuses on assessment and treatment of malnutrition. Malnutrition (both under- and overnutrition) is frequently present during cancer treatment and has substantial implications for both survival rates and quality of life. In a prospective cohort study with more than 130 participants, we found that low levels of physical activity and tube feeding were the main contributory factors to increase in weight and fat mass during treatment. At this time we are preparing intervention studies in collaboration with University of Applied Sciences Utrecht to improve levels of physical activity and dietary intake during treatment. Other areas of our research on nutritional status are: Estimation of energy and protein requirements in the first weeks after diagnosis. It is hypothesized that newly diagnosed children lose weight and muscle mass due to increased metabolic rate and cachectic processes. However, evidence for this hypothesis is lacking. Development of methods to assess lean body mass and fat mass in clinical practice in order to prevent deterioration by taking timely measures. Evaluation of methods of feeding: enteral vs parenteral and nasogastric tube feeding vs PEG tube. To date, no consensus has been reached on which intervention should be used. The research focuses on patient preferences, efficacy of feeding, and complications of the different methods. Development of international guidelines for nutrition. Dr. Brinksma chairs the core group of this guideline in collaboration with the COG, Sick Kids in Canada and POCG United States. 146

147 NAAM: Eva Clemens Promovendus Naam Centrum: Erasmus MC Sophia Kinderziekenhuis / Prinses Máxima Centrum voor Kinderoncologie Naam Research groep: Toxiciteit Supervisors: M.M. van den Heuvel-Eibrink & A.C.H. de Vries Abstract/Beschrijving eigen research project (max. 250 woorden): (voor promovendi, postdocs, klinische research fellow, klinisch projectleider) Currently, the long-term survival of childhood cancer exceeds 80% due to improved treatments. Platinum derivatives are the basis of a family of chemotherapeutic agents, successfully used to treat solid tumors. However, their anti-tumor efficacy can cause severe side-effects for children. Hearing loss is a relevant side effect of platinumtreatment and can influence speech and language development, subsequent socialemotional development as well as educational achievement. Ototoxicity has been described in a variable frequency (11-73%) in childhood cancer survivors (CCS). Although several non-genetic risk factors were identified, such as type, initial and cumulative dosages of platinum agents, cranial irradiation, and patient s age, these factors explain only partially the inter-individual variability in ototoxic responses to platinum. This led to the hypothesis that genetic factors may render certain individuals more susceptible to the adverse effects of platinum derivatives. Results of previous studies vary, which may be due to sample size, case-control definitions and choice of selected candidate genes. The project is part of the EU Seventh Framework Programme and the determinants of ototoxicity, including genetics, after treatment with platinum derivatives will be studied. 147

148 NAAM: Sarah Clement Promovendus Naam Centrum: Emma Kinderziekenhuis/AMC Naam Research groep:endocrinologische effecten van tumorbehandeling op de kinderleeftijd Promoter: Prof.dr. H.N. Caron, co-promotoren: dr. H.M. van Santen en dr. L.C.M. Kremer Abstract Is Outcome of Differentiated Thyroid Carcinoma Influenced by Tumor Stage at Diagnosis? Authors: S.C. Clement, 1,2 L.C.M. Kremer, 2,3 T.P. Links, 4 R.L. Mulder, 2 C.M. Ronckers, 2,3 B.L.F. van Eck-Smit, 5 R.R. van Rijn, 6 H.J.H. van der Pal, 2,3,7 W.J.E. Tissing, 3,8 G.O. Janssens, 9 M.M. van den Heuvel-Eibrink, 3,10 S.J. Neggers, 3,11 E.J.M. Nieveen van Dijkum, 12 R.P. Peeters, 11 H.M. van Santen 13 Author affiliations: 1 Department of Pediatric Endocrinology, Emma Children s Hospital/Academic Medical Center, Amsterdam, the Netherlands 2 Department of Pediatric Oncology, Emma Children s Hospital/Academic Medical Center, Amsterdam, the Netherlands 3 Dutch Childhood Oncology Group (DCOG-LATER), The Hague, The Netherlands. 4 Department of Endocrinology, University Medical Center, University of Groningen, Groningen, the Netherlands 5 Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands 6 Department of Radiology, Emma Children's Hospital/ Academic Medical Center, Amsterdam, The Netherlands 7 Department of Medical Oncology, Academic Medical Center, Amsterdam, The Netherlands, 8 Department of Pediatric Oncology, University Medical Center Groningen (UMCG), University of Groningen, Groningen, The Netherlands 9 Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands 10 Department of Pediatric Hematology/Oncology, Erasmus MC/Sophia Children s Hospital, Rotterdam, The Netherlands 148

149 11 Department of Internal Medicine/Endocrinology, Erasmus MC-University Medical Center, Rotterdam, The Netherlands 12 Department of Pediatric Surgical Center Amsterdam, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands 13 Department of Pediatric Endocrinology, Wilhelmina Children s Hospital/ University Medical Center Utrecht, The Netherlands. Abstract Background: There is no international consensus on surveillance strategies for differentiated thyroid carcinoma (DTC) after radiotherapy for childhood cancer. Ultrasonography could allow for early detection of DTC, however, it is unclear whether this is of value since the prognosis of DTC is excellent. We addressed the evidence for answering the question: Is outcome of DTC influenced by tumor stage at diagnosis? Methods: A multidisciplinary working group answered the following sub-questions: Is recurrence or mortality influenced by DTC stage at diagnosis? If early-stage DTC results in less aggressive treatment, does it contribute to a decline in complications of surgery or radioiodine therapy?' All literature was systematically reviewed and conclusions were drawn based on the level of evidence (A: high, B: moderate to low, C: very-low). Results: In children, level C evidence was found that early-stage DTC is associated with lower recurrence or mortality rates. No evidence was found that it influences morbidity rates. In adults, clear evidence was found that early-stage DTC is a favorable prognostic factor for recurrence (level B) and mortality (level A). Additionally, more extensive surgery increases the risk to develop transient hypoparathyroidism (level A) and higher doses of radioiodine increases the risk to develop second primary malignancies (level B), in adults. Conclusion: Identification of DTC at an early stage is beneficial for both children (very-low level evidence) and adults (moderate to high level evidence), even considering that the overall outcome is excellent. These results are an important cornerstone for the development of future guidelines for childhood cancer survivors at risk for DTC. 149

150 NAAM: Ivana van der Geest Promovendus Naam Centrum: Naam Research groep: Princess Máxima Centre for Pediatric Oncology, in close collaboration with Erasmus MC Sophia Kinderziekenhuis Toxicity & Quality of Life Supervisors: M.M. van den Heuvel-Eibrink & A.S.E.Darlington, R.Pieters Abstract: Although survival rates of childhood cancer have increased tremendously over the past decades, still 25% of children will eventually die due to disease progression or early treatment toxicity. Whereas adult palliative care has received substantial attention in terms of research leading to evidence-based practice, paediatric palliative care only recently gained more attention. Nowadays, palliative care is regarded as integrated in care for the child and its family, and ideally starts early in the diagnostic phase of a life-limiting illness. In addition, it is important to stress that palliative care is extended beyond the child s lifetime, as it encompasses care for the family after the child s death as well. As previously established by Himelstein and colleagues, important domains of palliative care are 1) physical care, 2) psychosocial care and bereavement care, 3) spiritual care, 4) advance care planning and 5) practical care. The first aim of my thesis is to explore the perspectives of parents and health care professionals with these domains of paediatric palliative care, the second aim is to investigate the long-term impact of paediatric palliative care on parents, siblings and health care professionals. 150

151 NAAM: Marissa Anna Hermina den Hoed Promovendus Naam Centrum: Prinses Maxima Centrum,ism ErasmusMC-Sophia Kinderziekenhuis Begeleiders: R.Pieters, S.Pluijm, MM van den Heuvel-Eibrink Naam Research groep: Toxicity Research interesses/expertises Epidemiology / Statistiek Bone Mineral Density Obesitas Acute Lymphoblastic Leukemia Methotrexate Abstract Het research project bestaat uit het onderzoek naar korte en lange termijn gevolgen van de behandeling van kinderkanker. We kijken naar de effecten van behandeling op de botdichtheid, omdat we zien dat kinderen een lagere botdichtheid hebben door chemotherapeutica met tot gevolg een verhoogd risico op fracturen. Ook onderzoeken we of de botdichtheid gerelateerd is aan het wel of niet krijgen van onsteking en afsterving van het bot (osteonecrose). Graag willen we gaan voorspellen welke riscofactoren er voor zorgen dat patienten een lage botdichtheid ontwikkelen door de therapie, zodat deze patienten onder controle gehouden kunnen worden om complicaties van een lage botdichtheid te voorkomen. Tevens wordt het effect van gewicht op de overleving bij kinderen met leukemie, en genetische variatie in methotrexaat toxiciteit 151

152 NAAM: M.M. van den Heuvel-Eibrink UHD X Postdoc x Klinisch-projectleider X Groepsleider Naam Centrum: Prinses Maxima Center in close connection with and supervising projects in Erasmus MC-Sophia KinderZiekenhuis Naam Research: 1. Myeloide mailigniteiten(shared leadership CM. Zwaan/M.Fornerod) 2. Toxicity (during and after childhood cancer treatment) 3. Renal tumours Research interesses/expertises : Translational research on Renal tumors, Quality of Care and Cure(direct and late side effects), Myeloid malignancies 1. Toxicity research groep The main focus is the identification of clinical, and genetic determinants of early and late toxicity. The main focus is on endocrine toxicity.(metabool syndroom,fertiliteit, osteopenie, lichaams samenstelling), ototoxicity and psychological factors. (see further application forms L.Warris, M. den Hoed, S.Pluijm, E. Clemens, IMM van der Geest, M.Wijnen, B.Boon, A van Noortwijk) 2. Renal tumours: Renal tumor research involves identification of clinical characteristics and survival, and particular the identification of high risk categories of remnal tumors. Unraveling high risk phenotypes and the molecular and genetic deteterminants is important for designing novel treament strategies. In addition, the design of regimens that involve reduction treatment is important to avoid serious direct and late side effects. Ongoing: Clearcell sarcomas in children, clinical and molecular determinants of outcome. S.Gooskens(zie beschrijving Gooskens) Comprehensive Molecular analysis of nephroblastoma(a.ooms) Voor myeloid malignancies: see description research groep myeloid malignancies (EMC) for ongoing postdoc projects Ongoing PhD projects: J.D.E. de Rooij, molecular characterization of NUP98 positive pediatric AML J.Obenauer, Molecular background of clonal evolution of pediatric myeloid malignancies 152

153 NAAM: Mischa Keizer Promovendus Naam Centrum: Department of Immunopathology, Sanquin Research and landsteiner Laboratory AMC, University of Amsterdam, Amsterdam, the Netherlands Emma Children s Hospital, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands Naam Research groep: Immunpathologie (Sanquin) Kinderoncologie, Kinderimmunologie (EKZ,AMC) Chemotherapeutic agent Asparaginase directly inhibits the activation of the classical and lectin pathway of complement. Mischa P. Keizer 1,2*, Cathelijn Aarts 1, Angela M. Kamp 1, Huib N. Caron 2, Marianne D. van de Wetering2, Diana Wouters 1 and Taco W. Kuijpers 2,3. 1 Department of Immunopathology, Sanquin Research and Landsteiner laboratory AMC, University of Amsterdam, Amsterdam, the Netherlands. 2 Emma Children s Hospital, Academic Medical Center (AMC), University of Amsterdam, Amsterdam, the Netherlands. 3 Department of Blood Cell Research, Sanquin Research and Landsteiner laboratory AMC, University of Amsterdam, Amsterdam, the Netherlands. The introduction of Asparaginase (ASNase) has greatly benefitted the treatment of ALL and has become a standard and successful component of leukemia-therapy. The reduction of extracellular asparagine, an essential amino acid for leukemic cells, into L-aspartic acid and ammonia selectively induces apoptosis due to suppression of cellular protein synthesis and nutritional deprivation. An increased incidence of thrombosis is associated with the use of ASNase and represents a potentially reversible cause of morbidity and mortality. Although this association has been confirmed in several clinical studies, the precise mechanism that causes these thromboembolic events remains unclear but has been attributed to reduced biosynthesis of coagulation proteins. The complement system and the coagulation pathway show a high degree of functional and phylogenetic similarity. There is increasing evidence supporting interaction between both systems. We therefore hypothesized that ASNase is able to exert an inhibitory effect on the complement system. Using an ex vivo setting, we show that ASNase is able to interact with proteases of the complement system and hereby significantly reduces the activation of the classical and lectin pathway of complement. In vivo a reduced activation of the complement system in pediatric ALL patients shortly after infusion of ASNase was seen. In contrast to previous studies, we here show that ASNase is able to directly inhibit different complement proteases, independent of protein synthesis. This study may provide a novel insight into the interaction of ASNase with serum proteins. 153

154 NAAM: Mariëlle Klein Hesselink Promovendus Naam Centrum: Universitair Medisch Centrum Groningen Naam Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract Differentiated thyroid carcinoma (DTC) during childhood is rare. Children with DTC present more frequently with advanced disease compared with adults. Nevertheless, the prognosis of childhood-onset DTC is excellent. The treatment is comparable in children and adults and consists of (near) total thyroidectomy and ablation therapy with radioactive iodine (131-I), followed by TSH suppressive therapy. Long-term follow-up data in children are limited, and especially data about long-term morbidity and quality of life (QoL) are lacking. Furthermore, it is not known if there is a relation between the presence of somatic mutations and the clinical course in children with DTC outside the Chernobyl region. More knowledge on the pathophysiological background and treatment related damage might result in recommendations regarding (patient tailored) treatment of pediatric patients. More insight in QoL and determinants of the psychosocial sequelae of childhood-onset DTC may improve aftercare. The Beatrix Children s Hospital and the Department of Endocrinology of the UMCG have initiated a multicenter study to evaluate the late effects of treatment and QoL in patients with childhood-onset DTC. All university medical centers in the Netherlands are involved. In collaboration with the University Hospital in Essen, Germany, thyroid tumors are analyzed for the presence of BRAF mutations and RET/PTC translocations. The project is funded by a grant from the Dutch childhood cancer fund KiKa. The study is closed and 105 patients are included. Currently, analyses are being performed. The results will be presented in the near future. 154

155 NAAM: Nicoline Kuiken Promovendus Naam Centrum: UMCG Naam Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract Mucositis, a severe side effect of chemotherapy and radiotherapy, is a complex inflammatory reaction of the mucous membranes of the alimentary tract. Mucositis can be subdivided in oral and gastrointestinal mucositis (GI mucositis), and can significantly affect the nutritional status and influence the quality of life. Moreover, the symptoms and consequences of mucositis eventually cause a delay of the next chemotherapy cycle, a reduction of the doses or even discontinuation of the regimen, which eventually affects survival. The aim of this project is to study possible interventions for the treatment or prevention of GI mucositis. Therefore we use different growth factors, minimal enteral feeding and TNFalpha inhibitor, in our previous established rat model of MTX-induced mucositis. Furthermore we study the feeding strategy during GI mucositis in two clinical studies. First, we study the current feeding strategy during GI mucositis in pediatric cancer patients in an observational study. Second, we compare tube feeding with TPN in adult stem cell transplantation patients. Considering oral mucositis in this project, we perform a double blind placebo controlled multicenter clinical trial to determine the effect of divergent low level laser therapy as treatment for oral mucositis in pediatric cancer patients. 155

156 NAAM: Saskia Pluijm Postdoc Naam Centrum: Naam Research groep: Erasmus MC Sophia Kinderziekenhuis en Princess Maxima Centrum (PMC), Utrecht Toxicity werkgroep leider: Dr. M.M. van den Heuvel-Eibrink Research interesses/expertises Epidemiologie en biostatistiek (o.a. cohortstudies, predictiemodellen, multivariate analyses) Bijwerkingen en late effecten van kinderkanker (m.n. op bewegingsapparaat) Bewegen, voeding en leefstijl Abstract: Er is steeds meer aandacht voor de bijwerkingen die kunnen optreden tijdens behandeling en de chronische late effecten van kinderkanker. Ongeveer 75% van de overlevenden van kinderkanker ontwikkelt minimaal een laat effect. In het project worden de korte en lange termijn effecten van behandeling van kinderkanker op het bewegingsapparaat onderzocht, waaronder verminderde botdichtheid, osteonecrose en spiermassaverlies). Het is niet bekend hoe vaak deze effecten precies voorkomen en welke factoren, genetische, hormonale, levensstijl (voeding, roken en bewegen) en/of behandelings-gerelateerde factoren (bestraling, chemotherapie, dexamethasone) deze kunnen beïnvloeden. De kennis die we opdoen op basis van epidemiologische cohort studies gebruiken we om preventieve maatregelen (bijvoorbeeld aanpassen van de medicatie, bevorderen actieve leefstijl of eiwitrijk dieet) te ontwikkelen, en op effectiviteit te onderzoeken in gerandomiseerde studies. Tevens ontwikkelen we predictiemodellen om kinderen en overlevers met een grote kans op bijwerkingen vroegtijdig op te sporen. Op bovenstaand onderwerp ben ik copromotor van Marissa den Hoed. Tevens consulteer ik promovendi en studenten op het gebied van methodologie en statistiek. 156

157 NAAM: Erik Loeffen Promovendus Naam Centrum: Universitair Medisch Centrum Groningen Naam Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract Our research project titled Towards evidence based guidelines for supportive care in childhood oncology focuses on the development of Clinical Practice Guidelines (CPGs) for the supportive care of childhood cancer. CPGs aim to bridge the gap between research and clinical practice and are regarded as powerful tools to improve the quality of care and reduce variation in practice. In this project we aim to develop these supportive care CPGs, implement them and monitor their use / effect, and set up the a supportive care research agenda for the next decade. The development of the CPGs is split up in various phases: 1. Supportive care topic prioritization by professionals; a Delphi study 2. Explore current supportive care practice; concordances and discordances between Dutch pediatric oncology hospitals 3. Parents and patients view on topic prioritization and shared decision making; a focus group study 4. Actual development of CPGs; literature searches, evidence selection and either writing a new guideline or adapting an existing guideline. Results from the already performed phases are: 1) professionals decided the top 10 topics for supportive care guidelines to be infection, sepsis, febrile neutropenia, pain, nausea/vomiting, restrictions in daily life and activities, palliative care, procedural sedation, terminal care and oral mucositis. 2) from this top 10 we explored daily practice in the pediatric oncology hospitals in the Netherlands, where we found discordant practice among the hospitals in 3 out of every 4 topics, underlining the relevance of new CPGs, optimizing care and outcomes in childhood cancer patients. 157

158 Endocrine consequences of pediatric oncology treatment. PI HM van Santen, MD PhD Pediatric Endocrinologist WKZ/UMCU, Utrecht, The Netherlands Prevention and Detection of Endocrine disorders during and after cancer treatment in children. PI : Dr HM van Santen, MD PhD Senior investigators: Prof Dr HN Caron Dr LC Kremer PhD student: Drs S Clement 1. Endocrine disorders after treatment with 131 I-MIBG for neuroblastoma Thyroid disorders after MIBG - Goal: prevention of thyroid damage due to radiation exposure with 131I-MIBG Study 1a: The incidence of thyroid and parathyroid disorders ten years after the introduction of a new thyroid protection during 131I-MIBG treatment in children with neuroblastoma PI : Dr H.M. van Santen Senior investigators: Dr G.A. Tytgat Dr B van Eck-Smit Dr LC Kremer Prof H.N. Caron Study 1b Thyroid function after the use of diagnostic 123I-MIBG PI : Dr H.M. van Santen Senior investigators: Dr G.A. Tytgat Dr B van Eck-Smit Dr LC Kremer Prof H.N. Caron Study 1c Genome-wide sequencing for the identification of potential genomic denominators between tumorgenesis factors in neuroblastoma and differentiated thyroid carcinoma in children PI : Dr H.M. van Santen, pediatric endocrinologist (WKZ, UMCU) Senior investigators: Dr J.J. Molenaar, research oncogenomics(amc) Dr G.A. Tytgat, pediatric oncologist (AMC) Prof. dr. R. Versteeg, research oncogenomics (AMC) Prof H.N. Caron, pediatric oncologist (AMC) Gonadal dysfunction after MIBG Study 1d Hypergonadotropic Hypogonadism in Neuroblastoma Survivors PI : Dr H.M. van Santen Senior investigators: Dr G.A. Tytgat Dr BLF van Eck-Smit Dr M.M. van den Heuvel-Eibrink Dr W v Dorp Dr H vd Pal Dr C Ronckers Dr LC Kremer Prof H.N. Caron 158

159 2. Early detection of Radiation-induced Thyroid cancer Study 2a: Clinical Presentation and Outcome of Differentiated Thyroid Carcinoma in Patients with a Previous History of Radiation for Childhood Cancer PI : PhD students : HM van Santen S Clement, M Klein-Hesselink Senior investiagators; Dr L Kremer Dr H vd Pal Dr C Ronckers Dr W Tissing Prof Dr T Links Study 2b: International Harmonization Group for Thyroid Toxicity (nodules and carcinoma) in CCS Evidence Based Guideline for Screening and Follow-up of Thyroid Nodules and Carcinoma after Exposure to Irradiation in Childhood Cancer Survivors PI s : H.M. van Santen, P.C. Nathan Coordinator: S.C. Clement Advisors: L.C.M. Kremer, M.M. Hudson, R. Skinner, R Mulder 3.Detection DEtection and Therapy of Early endocrine disorders after Childhood Cancer Treatment - DETECT-study PI : Dr HM van Santen PhD Student : SC Clement Senior investigators : Dr. A.Y.N. Schouten-van Meeteren, pediatric oncologist Dr. L.C.M. Kremer, pediatrician (AMC) Prof. dr. H.N. Caron, pediatric oncologist (AMC) Participating hospitals: Academic Medical Center, Amsterdam VU Medisch Centrum, VUmc Amsterdam Sophia Children s Hospital, Erasmus MC Rotterdam Beatrix Children s Hospital, UMCG Groningen St Radboud ziekenhuis, UMCN Nijmegen Leiden Medical Center, LUMC, Leiden Wilhelmina Children s Hospital, UMCU Utrecht 4. Endocrine consequences after treatment for childhood craniopharyngioma Study 4.1 Risk factors for development of hypothalamic obesity after treatment for childhood craniopharyngeoma PI : Dr HM van Santen/ Dr. A.Y.N. Schouten-van Meeteren Student : R Meijneke Study 4.2. Fluctuations in serum sodium concentration and neurological consequences in children with diabetes insipidus after neurosurgical intervention: a national cohort analysis. PI : Dr HM van Santen Student : R Kruis Senior investigators : Dr. A.Y.N. Schouten-van Meeteren Study 5. Endocrine Disorders among Survivors of Childhood Head and Neck Rhabdomyosarcoma PI : Dr JH Merks Senior investigator: Dr HM van Santen Prof H.N. Caron PhD Students Drs S Clement Drs R vd Schoot 159

160 AAM: Esther Sulkers Postdoc Naam Centrum: Universitair Medisch Centrum Groningen (UMCG) Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract In February 2015, I obtained my PhD degree at the University Medical Center Groningen. My thesis was about psychological adaptation to childhood cancer. Most of my research has focused on psychological mechanisms underlying resilience in children with cancer (curative patients aged years) during the first year post-diagnosis. I also looked into the course of caregiving stress (the difficulty/tension that may be experienced when giving care) in parents (mothers) of childhood cancer patients during this period of time. The findings of the study revealed that caregiving stress is an important factor in understanding parental adjustment to childhood cancer. My current postdoctoral position provides opportunities to continue conducting research in pediatric oncology. My main research interest at the present is to develop new lines of research in the field of pediatric (oncology) caregiving. Based on the fact that a large part of pediatric oncology treatment is given on an outpatient basis, the parents are faced with serious responsibilities (e.g. the delivery of enteral feeds, the administration of medication, interpreting the meaning and urgency of side-effects). Caregiving requires knowledge, skills, and judgment to carry out the tasks of care. When not done properly caregiving can be hazardous for the child (e.g. medication errors, failures in interpreting patient symptoms). In sum, both the caregiving responsibility itself, as the time involved and interference with other roles and plans for the future, may take a huge toll on the parent physically and emotionally and indirectly affect the child with cancer. Research interests: Gender differences (mother vs. father) in caregiving Determinants (socio-demographic factors, dispositional characteristics, aspects of the healthcare system) of: o caregiving experiences o caregiving competence Spousal support in the context of caregiving Caregiving experiences and child outcomes (e.g. child distress) Caregiving competence in relation to adherence, adverse events and healthcare use. Patterns of caregiving experiences in relation to parental physical and mental health Cross-cultural differences in caregiving (experiences) 160

161 NAAM: Wim Tissing Groepsleider Naam Centrum: University Medical Center Groningen Naam Research groep: Decreasing side effects of the treatment of childhood cancer patients Abstract Decreasing side-effects of the treatment of children with cancer improves mortality, morbidity and quality of life. Therefore, improving supportive care is of great importance. Our research line involves 3 items. First, mucositis. Using a rat model, we perform preclinical studies on the prevention and treatment of gastro-intestinal mucositis, but also on the function of the gut during mucositis with respect on the possibilities of nutrition. The results of these studies are subsequently studied in patient studies, both in children and in adults. Secondly, we study febrile neutropenia in children with cancer, from which many children suffer during their treatment. By looking for better decision tools on who is at high risk for complications and who s not, we try to improve care for those at great risk, and to keep those at lowest risk out of the hospital. Thirdly, we do studies on the nutritional state in children with cancer. Knowing that the nutritional state is of importance for eg infectious complications but also for survival, improving nutritional state is clinically very relevant. Lastly, we are involved in the development evidence based guidelines for supportive care and their implementation. Internationally we collaborate with many other centers eg the Gut Microbiome and Mucositis Research Group, university of Adelaide,Australia (mucositis), Bob Philips, PICNICC collaboration, University of York, UK (infections), and Lilian Sung and Lee Dupuis, Sick Kids, Toronto (guideline development). 161

162 NAAM: M.D. van de Wetering Klinisch-projectleider Naam Centrum:AMC/EKZ Naam Research groep:supportive care Abstract 1) ARISTOCATHS preventing catheter related infection with ethanol lock solution RCT PhD student R Schoot Thesis 2015 collaboration with Hematology Dr C van Ommen The Aristocaths study is a randomized, double blind clinical trial in supportive care. The objective is to evaluate the efficacy and safety of ethanol lock solution for prevention of catheter-related infections in children treated for cancer compared to standard heparin solution. Results will be published in ) COMPLEMENT study PhD student M Keizer Thesis 2015 collaboration with Clinical immunology Prof Dr T Kuijpers Complement activation defects in pediatric oncology patients: hidden factors contributing to the increased risk of infection Single centre study, results will be published in ) Thromboprophylaxis in Children treated for Acute Lymphoblastic Leukemia with Low-molecular weight heparin a randomized controlled trial (TropicALL study) PhD student I Klaassen (start 2014) collaboration with Hematology Dr C van Ommen 162

163 The aim of this study is to assess the effect and safety of thromboprophylaxis by high prophylactic dose LMWH in children treated for primary ALL on the overall incidence of symptomatic VTE. In addition, we will investigate the pathogenesis of VTE during ALL treatment by exploring the presence of potential clinical risk factors and hematological biomarkers to enable identification of high risk patients for VTE. 4) Restoring fertility in infertile childhood cancer survivors: bringing autotransplantation of human spermatogonial stem cells to the clinic Collaboration fertility clinic PI prof Repping Testicular biopsies in prepubertal boys diagnosed with cancer. Single center study 5) Clinical practice guidelines for fertility preservation in both boys and girls (PhD) A Font Gozalez started 2014 (collaboration L Kremer, Tissing, van de Wetering) fertility preservation guidelines for newly diagnosed children with cancer (0-18 years of age) (2 guidelines: male and female) as part of the European project PanCareLIFE 6) Towards evidence based supportive care guidelines in pediatric oncology (PhD) E Loeffen started 2014 (collaboration L Kremer, Tissing, van de Wetering) In order to improve supportive care for children treated for cancer in the Netherlands it is needed 1. to develop guidelines for supportive care for children with cancer by involving health care providers and patients/ parents 2. to implement the guidelines for supportive care for children with cancer for health care providers and patients/parents to identify gaps in knowledge and to set up a research agenda for the next decade were evidence is lacking 7) PANDA study: palliative care in children with advanced cancer.phd student C Jagt (thesis 2016) Collaboration; AYN Schouten-van Meeteren, pediatric oncologist, M Kars, nurse researcher;ma Grootenhuis, psychologist Prospective research in palliative care for children with cancer aims to gain detailed insight in the course of progressive childhood malignances and the abilities to reduce the burden of disease and gain quality of life despite infaust prognosis. 163

164 NAAM: Lidewij Warris Promovendus, MD Naam Centrum: Erasmus MC Sophia Kinderziekenhuis / Prinses Máxima Centrum voor Kinderoncologie Naam Research groep: Toxiciteit Supervisors: Dr. M.M. van den Heuvel-Eibrink, Dr. E.L.T. van den Akker, Prof.dr. R. Pieters Research interesses/expertises Clinical Research Neuropsychological side effects of treatment of childhood cancer Metabolic effects of treatment of childhood cancer Glucocorticoids Abstract: Double blind randomized intervention study aiming at reducing dexamethasone related side effects in children with acute lymphoblastic leukemia (ALL). The primary aim of this double-blinded randomized controlled trial is to diminish the dexamethasone-related neuropsychological side effects in children with acute lymphoblastic leukemia (ALL). Neuropsychological side effects, like behavioral difficulties, mood disorders and cognitive effects are reported during dexamethasone. We also study the effects on sleep, eating behavior, physical activity and metabolism. Based on recent studies the neuropsychological side effects arise by cortisol depletion of the mineralocorticoid receptor in the brain, since the endogenous cortisol production is suppressed by dexamethasone. We hypothesize that addition of a physiological dose of hydrocortisone could diminish the neuropsychological side effects of dexamethasone. Our preclinical pilot study showed no interference of hydrocortisone with dexamethasone efficacy in in vitro cell lines and ex vivo patients cells. Patients from the EMC, AMC, VUMC, UMCG and UMCU have been participating in the clinical trial. Last month we reached the final inclusion number of 50 patients. The data will be analyzed in the following months. 164

165 NAAM: Mark Wijnen Promovendus Naam Centrum: Erasmus Universitair Medisch Centrum Rotterdam Begeleiders: Dr. M.M. van den Heuvel-Eibrink, dr. S.J.C.M.M. Neggers, prof. dr. A.J. van der Lelij Naam Research groep: Toxicity Research interesses/expertises Brain tumors (including craniopharyngiomas) Late effects Endocrinology Cardiovascular disease risk factors Quality of life Abstract Craniopharyngiomen vormen een belangrijke groep hersentumoren, komen zowel bij kinderen als volwassenen voor en kennen een goede overleving. Helaas krijgen veel overlevenden van craniopharyngiomen te maken met gezondheidsproblemen op de lange termijn, veroorzaakt door tumor en/of behandeling. Hormoondeficiënties, visusstoornissen, neurologische uitvalsverschijnselen en ernstig overgewicht zijn late effecten waarmee veel patiënten die voor een craniopharyngioom behandeld zijn te maken krijgen. Eerder onderzoek heeft aangetoond dat deze lange termijn problemen kunnen bijdragen aan een verminderde kwaliteit van leven. Craniopharyngiomen kunnen op verschillende manieren worden behandeld, waarbij neurochirurgie en bestraling een belangrijke rol spelen. Verschillende vormen van bestraling, zoals conventionele radiotherapie, stereotactische radiotherapie en brachytherapie kunnen worden toegepast. Onderzoeken naar de verschillen op lange termijn tussen craniopharyngiomen die zich presenteren op de kinderleeftijd en op volwassenleeftijd leveren tegenstrijdige resultaten op. Ook zijn de late effecten en kwaliteit van leven na bepaalde behandelingen, zoals stereotactische radiotherapie en brachytherapie niet goed bekend. Meer onderzoek naar deze onderwerpen kan de lange termijn zorg en kwaliteit van leven van patiënten die voor een craniopharyngioom behandeld zijn verbeteren. Met dit onderzoeksproject willen we de verschillen op lange termijn tussen craniopharyngiomen welke zich presenteren op de kinderleeftijd en welke zich presenteren op volwassenleeftijd in kaart brengen. Hiernaast willen we de late effecten en kwaliteit van leven na verschillende behandelingsmodaliteiten beschrijven, waarbij we de nadruk willen leggen op stereotactische radiotherapie en brachytherapie. Als late effecten zullen ook cardiovasculaire risicofactoren in kaart gebracht worden. 165

166 PSYCHO-ONCOLOGY 166

167 NAAM: Boudewijn Boon Promovendus Naam Centrum: Prinses Máxima Centrum i.s.m. Technische Universiteit Delft Begeleiders: M. Rozendaal (TU Delft), P.J. Stappers (TU Delft), M.M. van den Heuvel- Eibrink (PMC), J. van der Net (WKZ) Naam Research groep: Meedoen = Groeien! Research interesses/expertises (trefwoordsgewijs, max.50 woorden): Development-Oriented Care Design Research Physical play Co-design with children Beschrijving eigen research project In het kader van ontwikkelingsgerichte zorg stelt dit project zich ten doel ontwerpinterventies te ontwikkelen die kunnen bijdragen aan de fysieke ontwikkeling van jonge kinderen met kanker.hierbij richten we ons op ontwerpinterventies die fysiek en vrij spel ontlokken in de ziekenhuisomgeving en daarbij positief bijdragen aan de (ziekenhuis)beleving van kinderen met kanker, alsmede aan hun fysieke fitheid en motorische vaardigheden. Tegelijkertijd trachten we met de ontwerpinterventies kinderfysiotherapie en revalidatie te ondersteunen door oefeningen aantrekkelijker te maken en beter te integreren in het dagelijks leven van kinderen en ouders. Het ontwerpen onderzoeksproces wordt op een participatieve wijze uitgevoerd; kinderen, ouders, broers en zussen, fysiotherapeuten, pedagogisch medewerkers en andere zorgverleners worden nauw betrokken als co-ontwerpers. Het project combineert ontwerp en onderzoek met als resultaat concrete implementeerbare interventies en kennis op het gebied van ontwerpen voor fysiek spel. 167

168 NAAM: Anouk van Eijndhoven Anders, namelijk Junior projectmedewerker Ontwikkelingsgerichte Zorg in Beeld Naam Centrum: Prinses Máxima Centrum Naam Research groep: Zorginnovatie onderzoek 168

169 NAAM: Martha Grootenhuis Groepsleider Naam Centrum: Emma Kinderziekenhuis AMC Naam Research groep: Pediatric Psycho-Oncology Research interesses/expertises Psychosocial outcomes; Quaility of Life, anxiety, depression, PTSS: Patient reported outcomes in clinical practise Intervention development: empowerment; Emental healh Neuopsychological Screening and monitoring Involved in projects / PhD Students: Marieke de Ruiter (Prisma), Simone Sintnicolaas (Improve), Sasja Schepers (Improve), Charissa Jagt (PANDA), Lisa Verberne (PANDA), Lindseay Steur (Sleep), Marieke de Vries (postdoc Yield), OGZ in Beeld 169

170 NAAM: Marijke Kars X Postdoc Naam Centrum: UMCUtrecht Naam Research groep: Julius Centrum, Medical Ethics Abstract Main focus of research: (paediatric) palliative care, end-of-life decision-making, parenting the chronically ill child and illness perceptions (parent and child perspective) Finished projects The lived experience of parents of children with ALL: a qualitative study exploring the parents perception and experiences during the first year after their child s diagnosis (Funding: 1e geldstroom UMCU) Parenting the chronically ill child: a qualitative exploration of the parents experiences with providing care and raising their chronically ill child (Funding: Landelijke Stichting Beheer Kruiswerk) The PRESENCE-study: Parenting and palliative care in paediatric oncology, a multicentre study into EOL care in paediatric oncology (KWF UU ) Current projects: Follow up and evaluation of transmural case management in paediatric palliative care (ZonMw ). Focus of this study is the evaluation of case management and of anticipated palliative care in paediatrics and paediatric oncology. Advanced Care Planning; an Innovative Palliative Care Intervention to Improve Quality of Life in Cancer Patients - A Multi-Centre Cluster Randomized Clinical Trial. This study is conducted in close collaboration with the Erasmus MC (Agnes van der Heide et al.) who initiated this study (FP7 European Union). Future plans: State of the art-study: aimed at exploration the process of death and dying in paediatric oncology. Collaboration is sought with Joanne Wolfe (USA), Erna Michiels (ErasmusMC, Meggie Schuiling Stichting PAL, SKION) A study on advance care planning in paediatric oncology: identification of the building blocks of an advance care planning intervention in paediatric oncology 170

171 NAAM: Raphaële van Litsenburg Postdoc Naam Centrum: VU medisch centrum Amsterdam Naam Research groep: Kwaliteit van leven kinderoncologie SLAAP study: SLeep in children with Acute leukemia and Additional costs to the Parents; the effect on quality of life. Background The progress in treatment of pediatric malignancies has made psychosocial well-being increasingly important. Previous research has shown that sleep problems are more prevalent in children treated for acute lymphoblastic leukemia (ALL) and that they are negatively associated with quality of life (QoL). In addition, sleep disturbances in children affect parental functioning. Management of sleep problems may therefore be an important tool to improve QoL of the patients and the rest of the family. Additional costs to the parents as a consequence of their child s disease may also have a large impact on family functioning and QoL, but studies on the extent and effect of these costs are lacking. The main objectives of this research project are to study sleep (types of sleep problems, prevalence and risk factors) and costs to parents of children during and after treatment for acute leukemia, and to investigate their effect on QoL and psychosocial functioning. Plan of investigation Children ( 2 years) with ALL or AML and their parents will be included in this prospective, multicenter study. The main outcomes, sleep and QoL, will be assessed using validated questionnaires. Sleep will also be assessed with actigraphy. As a biomarker of circadian rhythm, morning urinary melatonin levels will be measured. Psychosocial burden, sleep and QoL of the parents will be evaluated at the same time. Possible/relevance for cancer research More insight in sleep disturbances will help design a future intervention study with the ultimate goal to improve QoL. Information on the exact nature and extent of the extra costs will lead to better counselling regarding financial consequences 171

172 NAAM: Patrizia D Olivo P.DOlivo@tudelft.nl Promovendus (Meedoen = Groeien! Project in samenwerking met TUDelft) Naam Centrum: TUDelft Naam Research groep: ID StudioLab - HICD section Analysing of the impact of the experienced burden of cancer on the social network of children with cancer to explore opportunities for product service systems. The research will focus on designing and validating Product Service Systems (PSS) that foster the development of children with cancer. The aim is to understand the impact of the experienced burden of cancer on children and their social network by specifically looking into the quality of relationships. Patients that experience longterm treatment need to maintain (and further build upon) the relationships: within their family, with their peers and within the healthcare system. We make the assumption that every relationship counts: each person in the social network can contribute to the wellbeing through active engagement. The method used for this project is research through design: in this project the intersection between design and the medical field will be explored. Design research method methods combine creativity and aesthetic sensitivity with engineering. During the project, tangible hypothesis are built such as demonstrator and prototypes. Research on the burden of cancer on the social network will be conducted through focus groups and interviews, co-creation and usability testing and co-creation. 172