BRCA1 and breast cancer: Similar studies on BRCA1 mutations are less conclusive, but suggest that mutations in the central part of the gene (nt 2401–4190) are associated with lower breast cancer risk (RR=0.71; 95% CI 0.58–0.86), and that mutations in the 3′ end (beyond nt 4191) could be associated with lower ovarian cancer risk (RR=0.81; 95% CI 0.66–1.00) (Thompson and Easton, 2002).