A prophylactic salpingo-oophorectomy reduces the risk of ovarian cancer by more than 96%, reduces the risk of breast cancer by 72% in patients with the BRCA2 mutation, reduces the risk of breast cancer by 39% in patients with the BRCA1 mutation, and also reduces the overall cancer-specific mortality [47,48,49]. The gene discussed is BRCA2; the disease is ovarian cancer.