In the 1990s, the two major breast cancer susceptibility genes BRCA1 and BRCA2 were identified (Miki et al., 1994; Wooster et al., 1995) revealing that harmful mutations in these genes confer to a cumulative disease risk by age 70 years of 65 and 45%, respectively (Antoniou et al., 2003). The gene discussed is BRCA2; the disease is breast carcinoma.