Do single nucleotide polymorphisms in xenobiotic metabolizing genes determine breast cancer susceptibility and treatment outcomes?

SNPs in CYP1A1, CYP2A1, CYP2B6, CYP2C, CYP2D6, CYP3A, GSTM1, GSTT1, GSTP1, SULT1A1, SULT1A2, UGT, and MTHFR are associated with breast cancer susceptibility; however, lack of such associations are also reported in some populations. The contradictory findings are explained on the basis of ethnic variation among populations and due to lack of proper sample size, detailed genotype-phenotype combinations and validation of gene expression studies at protein level. In this review, SNPs in these genes that have tremendous potential in identification of susceptible individuals, development of preventive strategies, treatment outcomes and their limitations are discussed.