Cumulative BRCA mutation analysis in the Greek population confirms that homogenous ethnic background facilitates genetic testing

High frequency of BRCA recurrent mutations in a consecutive series of unselected ovarian cancer patients

Hereditary predisposition to breast and ovarian cancer (HBOC) is diagnosed by molecular analysis of deleterious mutations in BRCA genes, allowing oncogenetic follow-up of patients and of their families. BRCA testing addresses only to HBOC families, using restrictive inclusion criteria based on familial history of cancer and age at diagnosis. Sporadic ovarian cancer has high incidence and mortality in Romania, with low median age of diagnosis and possibly a higher magnitude of hereditary contribution comparing to othe populations. However, sporadic ovarian cancers do not qualify for BRCA testing according to inclusion criteria, and a complete BRCA screening of all cancers is neither feasible nor recommended. Despite the large diversity of BRCA mutations worldwide, some recurrent mutations have higher frequencies in diverse populations. Precisely screening for recurrent mutations in a target population allows to rapidly identifying mutation carriers without sequencing the entire BRCA genes. In Romanian population and neighboring countries, several recurrent mutations have already been described. In a consecutive series of 50 sporadic ovarian cancer patients, not qualifying for BRCA complete testing, we screened for 9 most common BRCA mutations, by multiplex-PCR, RFLP and targeted Sanger sequencing. Our results revealed 6 different BRCA mutations in 8 unrelated patients, with a frequency of 16%, much higher than expected. We further recommend screening for the identified mutations in larger series of cancer patients. The results are highly beneficial to cancer patients, healthy relatives, and overall, considering prevention in cancer a priority, to public health system and future of oncogenetics in Romania

BRCA1/2 associated cancer susceptibility: a clinical overview

The most frequently identified genetic cause of breast cancer is the germline mutation of BRCA1 and 2 genes. The carriers of these mutations are at high risk for breast and ovarian cancers and increased risk for pancreatic and prostate cancers. Personal and family history are routinely used to identify individuals at risk for carrying such mutations. Genetic counselling is required to guide them through genetic testing and risk management. Positive testing corresponds to a deleterious mutation, whereas negative testing is considered as uninformative; variants of unknown clinical significance are also classified as uninformative.

The most effective risk reduction strategy involves bilateral prophylactic mastectomy and bilateral salpingo-oophorectomy, eliminating 90% of breast and 97% of ovarian cancer risks, respectively. Before and until such surgery, surveillance with physical examination, mammography and magnetic resonance mammography, starting at 25–30 years of age, are recommended for the early diagnosis of breast cancer; semi-annual surveillance with physical examination, transvaginal ultrasound and serum CA-125 is recommended for women who have not had prophylactic surgery. Carriers diagnosed with breast cancer run a high risk for a new breast primary and this information should be used accordingly. PARP inhibitors is a new class of antineoplastic agents, already approved for advanced BRCA1/2 mutant (germline or somatic) ovarian cancer.

Multigene panel testing may follow a negative BRCA genetic test, often identifying other genetic causes of cancer, expanding its role in oncology. Further adoption of PARP inhibitors, refinement in estimation of BRCA-associated cancer risks and wider population testing, through NGS technology, may become available in the near future.