Berrandou T, et al. - In a case–control study of 1,125 cases and 1,172 controls, the link between breast cancer risk and genetic variation in xenobiotics metabolism (XM) genes [seen as a set of single nucleotide polymorphisms (SNPs)] and in the XM pathway (seen as a set of genes) was studied by using a gene-set analysis method. Also, the interaction between variants in XM genes and tobacco smoking was also examined. Researchers analyzed genotyping data of 585 SNPs in 68 XM genes. A significant association was observed between genetic variation in the whole XM pathway and premenopausal breast cancer risk. Genetic variation in NAT2, CYP2C18, CYP2C19, AKR1C2 and ALDH1A3 was the predominant driver of this link. Current and previous smokers, but not never smokers, exhibited a link between the XM gene pathway and breast cancer. Overall, via their detoxification function of environmental pollutants, such as those contained in tobacco smoke, XM genes variants may be involved in breast carcinogenesis.