BREAST CANCER, FAMILIAL

A number of factors have been identified that increase the risk of breast cancer. One of the strongest of these risk factors is the history of breast cancer in a relative. About15-20% of women with breast cancer have such a family history of the disease, clearly reflecting the participation of inherited (genetic) components in the development of some breast cancers. Dominant breast cancer suceptibility genes, including BRCA1 and BRCA2, appear responsible for about 5% of all breast cancer. See related entries to: Breast cancer susceptibility genes; BRCA1; BRCA2.