MOLECULAR STUDIES IN THE PATHOLOGICAL DIAGNOSIS OF LYMPHOMA

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Brittney Reed
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1 MOLECULAR STUDIES IN THE PATHOLOGICAL DIAGNOSIS OF LYMPHOMA CIQC/CAP-ACP SEMINAR DAVID LE BRUN DEPARTMENT OF PATHOLOGY AND MOLECULAR MEDICINE QUEEN S UNIVERSITY KINGSTON, ONTARIO

2 This lecture aims to make attendees aware of: 1. The range of molecular tests that are commonly used in the pathological diagnosis of lymphomas 2. The manner in which these tests may be applied and interpreted in the context of scenarios that arise typically in diagnostic practice.

3 Mature B-cell Neoplasms According to the WHO Classification Chronic lymphocytic leukemia/small lymphocytic lymphoma B-cell prolymphocytic leukemia Lymphoplasmacytic lymphoma Splenic marginal zone lymphoma Plasma cell neoplasms Extranodal marginal zone B-cell lymphoma, also called MALT lymphoma Nodal marginal zone B-cell lymphoma Follicular lymphoma Mantle cell lymphoma Diffuse large B-cell lymphoma Mediastinal (thymic) large B-cell lymphoma Intravascular large B-cell lymphoma Primary effusion lymphoma Burkitt lymphoma/leukemia Hairy cell leukemia

4 Morphology and immunohistology are usually sufficient Clinical information, conventional microscropy and immunohistochemistry Immunophenotyping by flow cytometry ~10% Confident Pathological Diagnosis Molecular studies

5 1. PCR-based clonality testing Topics 2. Detection of MYC rearrangements in the diagnosis of Burkitt-like lymphoma 3. The challenge of small specimens

7 Germline configuration V 1 V 2 V ~50 D 1 D 2 D ~25 J 1 J 2 J 6 μ δ γ 3 γ 1 α 1 γ 2 γ 4 ε α 2 V-D-J rearranged Exponential amplification

8 Non-lymphoid Clone 1 Clone 2 Clone 3 Clone 4 Clone 5 Clone 6 Clone 7 Polyclonal

9 + - M

10 Application of Lymphoid Clonality Testing by PCR 1. Distinguish neoplastic from reactive lymphoid infiltrates 2. Determining the (T- vs. B- vs. non-lymphoid) lineage of a neoplasm 3. Evaluating anatomical dissemination of a lymphoproliferative disease (N.B. sensitivity is limited) 4. Establish clonal relationship between multiple lesions

11 Pitfalls Failed amplification due to poor DNA quality/quantity (ex., FFPE samples) Non-representative sample Nonspecific products from multiplex PCR reaction Failed amplification due to somatic hypermutation (especially FL) Spurious mono- or oligoclonal bands due to few lymphoid cells True oligoclonality in non-neoplastic processes

12 Expert Opin Med Diagn 1:451, 2007

13 Case 1

14 Case 2 CD20 S100

15 Case 3 Orbital mass in a 49 year-old man Specimen consisted of soft, pink tissue and measured 1.5 x 0.8 x 0.7 cm Tissue allocated between formalin fixation and freezing

18 CD20 CD3 CD5 CD21 BCL2 CD43 MZBL vs Kappa Lambda Reactive?

19 Factor that justify the use of clonality testing and contribute to success: Well-defined question: lymphoma versus chronic inflammation Absence of demonstrable immunophenotypic abnormality Sample of adequate size Availability of frozen tissue Prevalence of B-cells demonstrated by IHC

20 B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma Diffuse large B- cell lymphoma Burkitt lymphoma Common Mostly adults Treated with R-CHOP MYC translocations <10% Uncommon Mostly children Treated with intensive chemotherapy including CNS prophylaxis MYC translocations approach 100%

21 Burkitt Lymphoma Diagnosis based on a combination of clinical, pathological and cytogenetic findings Pathology and cytogenetics: Typical morphology Mature B-cell immunophenotype CD10+, BCL6+, BCL2- Ki-67 approaching 100% MYC translocation

22 B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL Has some, but not all, pathological features of Burkitt lymphoma Presents a pathological dilemma Presents a clinical dilemma MYC rearrangement may be associated with translocations involving BCL2 or BCL6 (i.e., double- or triple-hit lymphomas)

23 Chromosomal Translocations Involving MYC in Lymphoma J Clin Oncol 18:3707, 2000

24 chr14 IGH μ J D V MYC chr8 der14 IGH Eμ MYC

26 Case Mesenteric mass in a 55 year-old man

29 CD20 CD3 BCL6 Ki-67 CD10 BCL2 FISH indicated MYC rearrangement Dx: B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma

30 DLBCL vs. BL vs. B-UNC/BL/DLBCL? Numerous mitoses, prevalent Ki-67 expression and starry sky pattern? Yes MYC rearranged by FISH? Yes Perfect Burkitt morphology, CD10+, BCL6+, BCL2-? Yes BL No No No DLBCL B-UNC/BL/DLBCL

31 Farmer et al. Am J Clin Pathol 128:474, 2007

32 Needle biopsy from a lung opacity in a middle-aged man

34 CD20 Kappa Lambda CD3 CD43 CD5 Keratin Marginal zone B-cell lympoma vs Inflammation?

35 Flow cytometry from BAL specimen

36 Criteria for submitting tissue from cutting needle biopsies for flow cytometry: 1. The sample submitted for flow is no greater than the equivalent of a 0.5 cm-long core from an 18 gauge needle 2. The sample submitted for flow accounts for no more than 10% of the sample

37 Flow cytometry in small biopsy samples Case Bx type Specimen Cells (x10 6 ) Markers Lymphoid (%) Flow opinion Histopathology 1 needle Right para-? 0 2 nd nd Peripheral T-cell lymphoma? 2 needle Right chest wall 0 0 nd nd Plasma cell neoplasm 3 needle R supraclavicular node nd nd Inflammation and fibrosis 4 needle Right pelvis LN T-cell predominant, "non-diagnostic" Carcinoma 5 needle Left axillary node % B-cells, CD10+, CD5-, insufficient cells for light chains, "possible follicle centre cell lymphoma" Follicular lymphoma grade 1 6 needle Right groin LN B-predominant, kappa monotypic, CD5+, CD10-, FMC7-, "CW mantle cell lymphoma" Mantle cell lymphoma 7 endoscopic Tumour right orbit nd nd Carcinoma 8 endoscopic bx pyloric mass T-cell predominant, "non-diagnostic" Chronic inflammation 9 needle LN unknown location T-cell predominant, "non-diagnostic" Atypical lymphoid infiltrate 10 needle Left neck node 2 0 nd nd Classical Hodgkin lymphoma 11 needle Left cervical LN T-cell predominant, "non-diagnostic" Classical Hodgkin lymphoma 12 needle Mesenteric mass B-predominant, kappa monotypic, CD5-, CD10+, "CW follicle centre cell-derived lymphoma" Follicular lymphoma grade 2 13 endoscopic Bx L posterior nares 3 8 nd nd Chronic inflammation 14 needle Left axillary node B-predominant, lambda monotypic,cd5-, CD10+, FMC7-, "CW follicle centre cell-derived lymphoma" Follicular lymphoma grade 3A 15 needle Right inguinal LN B-cells 25%, lambda monotypic, CD5-, CD10+, "CW follicle centre cell-derived lymphoma" Follicular lymphoma grade 3B 16 needle LN tonsils B-predominant, lambda monotypic,cd5-, CD10+, "CW follicle centre cell-derived lymphoma" Follicular lymphoma grade 1 17 needle Left neck node nd nd Carcinoma 18 endoscopic Bx nasopharynx Mixed T- and B- cells, ligh chains polytypic, "non-diagnostic" Lymphoid hyperplasia 19 needle Right inguinal LN Mixed T- and B- cells, ligh chains polytypic, "non-diagnostic" Lymphoid hyperplasia 20 needle Right groin mass T-cell predominant, "non-diagnostic" Melanoma 21 needle Right axillary LN B-predominant, lambda monotypic, CD5+, CD10-, FMC7+, "CW mantle cell lymphoma" Mantle cell lymphoma 22 needle Left neck mass B-predominant, lambda monotypic, CD5-, CD10+/-, "CW lymphoma" Diffuse large B-cell lymphoma 23 needle Core needle bx spleen T-cell predominant, "non-diagnostic" Classical Hodgkin lymphoma Interpretable flow data obtained from 16/23 (70%) of cases Light chain monotypia detected in 7/8 (88%) B-lineage, non-hodgkin lymphomas False positive calls in non-lymphoma samples: 0/8 Classical Hodgkin lymphoma detected: 0/2

38 Needle biopsy of a retroperitoneal mass

41 CD20 CD3 CD5 BCL6 CD21 BCL2 Follicular lymphoma vs Other indolent lymphoma vs Reactive?

42 chr14 IGH V D J C chr18 BCL2 der14 Eμ

43 Immunostain for Bcl-2

45 Take Home Messages 1. In most cases, the pathological diagnosis of lymphoma may be made based exclusively on morphology and immunophenotype 2. Lymphoid clonality studies or FISH for rearrangements involving MYC or BCL2 may be useful to address specific questions under specific circumstances 3. These results should be interpreted conservatively and in the context of the clinical information and morphological and immunophenotypic findings 4. Results should be reported in the context of the morphological and immunophenotypic findings

LYMPHOMA. BACHIR ALOBEID, M.D. HEMATOPATHOLOGY DIVISION PATHOLOGY DEPARTMENT Columbia University/ College of Physicians & Surgeons

LYMPHOMA. BACHIR ALOBEID, M.D. HEMATOPATHOLOGY DIVISION PATHOLOGY DEPARTMENT Columbia University/ College of Physicians & Surgeons LYMPHOMA BACHIR ALOBEID, M.D. HEMATOPATHOLOGY DIVISION PATHOLOGY DEPARTMENT Columbia University/ College of Physicians & Surgeons Normal development of lymphocytes Lymphocyte proliferation and differentiation: