In the case of breastcancer, for example, prospective and retrospective studies have shown that prophylacticbilateral mastectomy is the intervention with higher breast cancer risk reduction inwomen with a mutation in the BRCA1/BRCA2 genes (reduction of up to 90%of the risk) (Hartmann et al.,2004) Prophylactic bilateral salpingo-oophorectomy in patients with mutationspromotes a 90% reduction in the risk of ovarian cancer and a 50% risk reduction forbreast cancer (Roukos, 2007). The gene discussed is BRCA2; the disease is ovarian cancer.