BRCA1 and breast cancer: Penetrance by the age of 70 years for breast cancer in BRCA1 mutation carriers has been estimated to be 64.6% (95% confidence interval (CI), 59.5–69.4%) and 61.0% (95% CI, 48.1–72.5%) in BRCA2 mutation carriers, meanwhile for ovarian cancer it is 48.3% (95% CI, 38.8–57.9%) for BRCA1 and 20.0% (95% CI, 13.3–29.0%) for BRCA2 mutation carriers [10].