Purpose: There is increasing evidence that BRCA1 and BRCA2 associated tumors may differ from sporadic cancers. The purpose of this report is to review the current state of knowledge of BRCA1 and BRCA2, the biology of associated tumors, and possible risk reduction strategies in women with these deleterious mutations.
Design and methods: We conducted an extensive literature search of all published articles (including Medline) on preclinical data on the function of BRCA1 and BRCA2, associated tumor pathology, and the clinical management for both unaffected carriers and affected patients.
Results: BRCA1 and BRCA2 are likely to act as tumor suppressor genes, and together with RAD51 operate in a common DNA damage response pathway implicated in double-strand repair. Breast cancers associated with BRCA1 are frequently of a higher grade, steroid hormone receptor negative, and appear to have a higher proportion of atypical or typical medullary subtype. Conversely, BRCA2 associated breast cancers do not differ significantly from sporadic cancers. No special tumor phenotype has been ascribed to BRCA1 or BRCA2 associated ovarian cancers. Guidelines for risk reduction strategies for the high risk unaffected carrier have been recommended by expert panels in the USA and Europe. Lifestyle changes, multi-modality screening, chemoprevention, and prophylactic oophorectomy and mastectomy, with their possible benefits and attendant risks are described. Finally, locoregional and systemic treatment in breast and ovarian cancers associated with these mutations, and differences between these and sporadic cancers are discussed.
Conclusions: Although the incidence of breast or ovarian cancers that can be attributed to BRCAI or BRCA2 mutations account for less than 5% of all cancers, these cancers may differ from sporadic cases in terms of tumor biology and phenotype. These differences may impact directly on clinical management of breast and ovarian cancer patients, and their relatives. Further recommendations of these patients are constantly changing as new information emerges on the clinical behavior of these cancers.