Abstract
Genetic predisposition is responsible for 5% 10% of all breast cancer cases. Therefore, the inherited susceptibility to breast cancer has been intensively investigated during the last 10 years. In particular, the identification of the breast cancer susceptibility genes BRCA1 (breast cancer gene 1) and BRCA2 and the current genetic testing for mutations in both genes are the basis for estimating disease risks for women with a strong family history of breast cancer and will provide important information on the prevention and treatment of familial breast cancer.