The risks of breast cancer associated with gene faults in BRCA1 and BRCA2 have been reported to vary from as little as 30% (especially BRCA2) to as high as 90% by age 70 years. However, most studies that assessed risk look backwards at what has happened in families rather than forwards. These studies make adjustments for biases, but include women born before 1930 when breast cancer incidence rates were much lower. We assessed breast cancer risk prospectively in 254 unaffected women with BRCA1 and 238 with BRCA2 mutations.Nineteen breast cancers occurred in BRCA1 and 23 in BRCA2. Estimates of risk to 70 years of were 55.1% for BRCA1 and 71.5% for BRCA2. Breast cancers were associated with stronger family histories especially for BRCA2. (By Prof. D Gareth Evans, http://jmg.bmj.com/content/early/2014/07/22/jmedgenet-2014-102336 )