While the lifetime risk of breast cancer is 12% in the general population [4], the cumulative risk by the age of 80 increases to 72% among BRCA1 mutation carriers and 69% among BRCA2 mutation carriers [5]; and with regard to ovarian cancer, the corresponding risk estimates are 1.3% in the general population [4], increasing to 44% and 17% among BRCA1 and BRCA2 carriers, respectively [5]. This evidence concerns the gene BRCA1 and breast cancer.