BACKGROUND: Every year, 60,000 women in Germany are found to have breast cancer, 
and 9000 to have ovarian cancer. Familial clustering of carcinoma is seen in 
about 20% of cases.
METHODS: We selectively review relevant articles published up to December 2010 
that were retrieved by a search in PubMed, and we also discuss findings from the 
experience of the German Consortium for Hereditary Breast and Ovarian Cancer.
RESULTS: High risk is conferred by the highly penetrant BRCA1 and BRCA2 genes as 
well as by other genes such as RAD51C. Genes for breast cancer that were 
originally designated as moderately penetrant display higher penetrance than 
previously thought in families with a hereditary predisposition. The role these 
genes play in DNA repair is thought to explain why tumors associated with them 
are sensitive to platin derivatives and PARP inhibitors. In carriers of BRCA1 
and BRCA2, prophylactic bilateral mastectomy and adnexectomy significantly 
lowers the incidence of breast and ovarian cancer. Moreover, prophylactic 
adnexectomy also lowers the breast-and-ovarian-cancer-specific mortality, as 
well as the overall mortality. If a woman bearing a mutation develops cancer in 
one breast, her risk of developing cancer in the other breast depends on the 
particular gene that is mutated and on her age at the onset of disease.
CONCLUSION: About half of all monogenically determined carcinomas of the breast 
and ovary are due to a mutation in one or the other of the highly penetrant BRCA 
genes (BRCA1 and BRCA2). Women carrying a mutated gene have an 80% to 90% chance 
of developing breast cancer and a 20% to 50% chance of developing ovarian 
cancer. Other predisposing genes for breast and ovarian cancer have been 
identified. Clinicians should develop and implement evidence-based treatments on 
the basis of these new findings.