A Guide to Inherited Breast and Ovarian Cancer Research and Services

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1 A Guide to Inherited Breast and Ovarian Cancer Research and Services Dr Lisa Jeffers Macmillan Genetic Nurse Counsellor Northern Ireland Regional Genetics Service

2 Inheritance The majority of breast/ovarian cancer is not due to an inherited condition, approximately 5-10% of breast cancer that occurs is due to an inherited predisposition (inherited breast cancer). Two major genes associated with familial breast/ovarian cancer are the BRCA1 and BRCA2 genes (<3%). Everyone has two copies of the BRCA1/BRCA2 gene a copy inherited from each parent. The BRCA1/BRCA2 gene plays an important part in correcting unwanted changes that occur in DNA. An alteration in just one of the two copies of the gene is sufficient to increase the likelihood of developing breast cancer.

3 several women who have had breast cancer and ovarian cancer on one side of the family breast cancer being diagnosed at a younger age than is usual a breast cancer diagnosed with grade 3 triple negative histology (ie it tests negative for oestrogen, progesterone and HER2 receptors), especially at a young age an individual who has had primary breast cancer more than once or had early breast cancer and ovarian cancer a male with breast cancer in a family where female relatives have also had breast cancer.

4 Using genomic information to sub-classify breast cancer Breast cancer is the most commonly diagnosed cancer in the UK, affecting around 1 in 11 women in Northern Ireland during their lifetime. Cancer is usually a disease of older people, so why do some women develop it at an earlier age? Do they have an increased predisposition to developing cancer? Is their cancer of a different type? Two things try to answer these questions: 1. Take a family history 2. DNA test for changes in genes known to be involved in increasing the likelihood of developing breast cancer. Ongoing advances mean that it is now possible to test a larger number of genes that are known to play a part in breast cancer risk.

5 NICE 164 NICE guidelines (164) state that genetic testing for BRCA1 and BRCA2 gene alterations should be available to women where there is a 10% or greater chance of carrying a gene mutation. Genetic testing is most useful if carried out in an affected member of the family first to establish the specific alteration for that family. If a gene alteration is identified in an affected family member, then other relatives can also be tested to see whether they carry the same gene alteration. This is known as predictive genetic testing. If there are no affected relatives available to test (eg if everyone who has had breast cancer is deceased) genetic testing may still be possible for unaffected women in the family if there is a strong family history of breast and/or ovarian cancer.

6 Eligibility for BRCA testing Testing score = 15 Testing unaffected score = 20 Pathology triple negative Lobular Hormone status Serous adenocarcinoma/epithelial

7 What does the diagnosis of this type of cancer mean for the family? The results of the DNA tests allows a doctor to sub-classify the type of breast/ovarian cancer and choose the appropriate treatment for someone who has a change in one copy of the BRCA1/ BRCA2 gene. A woman with one altered BRCA1/BRCA2 gene can have a lifetime risk of developing breast cancer of up to 80%. The lifetime probability of developing ovarian cancer is between 15% and 60%. This is an example of where genomic information can inform management and surveillance.

8 Inheritance pattern An individual with a gene alteration has a 1-in-2 (50%) chance of passing on the usual gene and a 1-in-2 (50%) chance of passing on the altered gene to each of their children, male or female.

9 This information means that adult members of a family can also be tested. Those found to have the change in the gene can be offered close surveillance to ensure early diagnosis, or preventative treatment to reduce the risk of breast cancer (for instance, risk-reducing mastectomy

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11 Other breast cancer genes TP53 PTEN CHEK2 ATM (ataxia telangiectasia mutated) BRIP1 PALB2 STK11 RAD51 Clinical utility of above findings remains uncertain

12 The Breast Cancer and Ovarian Cancer Susceptibility (BOCS) study Inclusion criteria Any individual with breast and ovarian cancer Any individual with bilateral breast cancer Any individual with male breast cancer Any individual with ovarian cancer who has at least one relative with ovarian or breast cancer Any individual in whom a BRCA1/2gene test has been performed.

13 GENPROS Analysing outcomes after prostate cancer diagnosis and treatment in carriers of rare germline mutations in cancer predisposition genes Men diagnosed with PCa are eligible for the study if they are either: known carriers of a germline mutation in a gene associated with PCa risk (e.g. BRCA1, BRCA2, HOXB13 and Lynch Syndrome genes) known not to carry a mutation in one of the genes above

14 Multiple Primary Tumours (MPT) Inclusion Patients with a histological diagnosis of multiple primary tumours (either at least two primary tumours at age <60 years or three primary tumours at age <70 years) and a clinical diagnosis of likely inherited cancer syndrome Exclusion Patients with a known underlying genetic cause of multiple primary tumour (e.g. BRCA1 mutation). Patients with a clinical phenotype that fits a known inherited cancer syndrome will be excluded until they have tested negative for a mutation in the relevant inherited cancer gene(s).

15 Cancer genetic referral guidelines Referrals can be made for individuals affected by cancer or for their close relatives. If possible, refer the affected person in the first instance. It is essential as much detail is given in the referral including the age of diagnosis and if known the names of affected individuals. Close relatives are first and second degree relatives. Affected relatives must be close relatives of each other, through either the maternal or the paternal side. In breast/ovarian cancer families, women related through unaffected men are considered close relatives (i.e. a paternal family history may still be significant). Few families have a mutation in a known cancer gene. For many it will not be appropriate to offer genetic testing. In general, a living relative affected by cancer is tested prior to offering testing to unaffected family members. This maximizes the chance of finding the family gene mutation if one exists. Not all individuals referred will be eligible for additional screening. Not all individuals referred will be offered a clinic appointment; some may receive a risk assessment by letter.