Li H, Terry MB, Antoniou AC, et al. - Since mutation carriers have high breast cancer (BC) risk and BRCA1 and BRCA2 hold importance in DNA repair, researchers investigated the links of alcohol intake and tobacco smoking with the risk of breast cancer in a large international pooled cohort of BRCA1 and BRCA2 mutation carriers. Employing Cox proportional hazards models, retrospective (5,707 BRCA1 mutation carriers; 3,525 BRCA2 mutation carriers) and prospective (2,276 BRCA1 mutation carriers; 1,610 BRCA2 mutation carriers) analyses of alcohol and tobacco intake were carried out. The HR from retrospective analysis and from the prospective analysis was 1.19 and 1.36, respectively, for BRCA1 mutation carriers. There was no link between alcohol intake and BC risk, for both carrier groups. Overall, an increased BC risk related to smoking during the pre-reproductive years was revealed for mutation carriers.