The compiled information indicates worse outcomes (higher recurrence risk or shorter breast cancer-specific survival) for the polymorphisms CYP1A1m2, CYP1B1*3, CYP2B6*2, *4, and *9, CYP3A4*1B, GSTP1A313G, and UGT2B7His268Tyr, whereas a beneficial effect is observed for the variant genotype GSTA1*B/*B (better overall survival) and for the GSTT1Null genotype (longer breast cancer-specific survival). This evidence concerns the gene CYP2B6 and breast cancer.