BRCA2 and breast cancer: In a retrospective case–control study of 981 BRCA1 and 330 BRCA2 carrier pairs, there was no effect of OC on breast cancer risk in BRCA2 carriers, but in BRCA1 carriers risk for early-onset (<40 years) breast cancer was increased in women who first used OC before 1975 (OR=1.42, 95% CI 1.17–1.75), who used OC before age 30 years (OR=1.29, 95% CI 1.09–1.52), or who used them for 5 or more years (OR=1.33, 95% CI 1.11–1.60) (Narod et al, 2002b).