BRCA1 and breast cancer: The cumulative breast cancer risk to age 80 is estimated at 72% and 69% for women with a BRCA1 or BRCA2 mutation, respectively.1 Prophylactic mastectomies and oophorectomies can substantially reduce this risk,2 but many women only learn of their mutation status at the time of a first cancer diagnosis or when a cancer occurs despite the preventative interventions.