BRCA1 and breast cancer: In a systemic analysis of 19,581 carriers of BRCA1 mutations, Rebbeck et al. identified that mutation clusters mapped to the 5′ (BCCR1, c.179 to c.505) and 3′ (BCCR2, c.4328 to c.4945 and BCCR2′, c.5261 to c.5563) regions of BRCA1 were associated with increased breast cancer risk, while mutations mapped to exon 11 were associated with increased ovarian cancer risk [28].