Studies have found that BRCA1 mutations lead to a breast cancer risk of 40 to 87% and an ovarian cancer risk of about 16 to 68% by age 70, while BRCA2 mutations lead to a breast cancer risk of 40 to 84% and an ovarian cancer risk of 11 to 27% by that age [1]. This evidence concerns the gene BRCA1 and breast cancer.