Tamoxifen, cytochrome P450 genes and breast cancer clinical outcomes

Abstract

Tamoxifen has a key role in the management of women with hormone receptor (HR) positive breast cancer. It is the endocrine treatment of choice in premenopausal women with HR positive breast cancer and is also clinically indicated in significant numbers of post-menopausal women who have relative contraindications to aromatase inhibitors. Tamoxifen is a pro-drug that is metabolised to its active metabolites by the cytochrome P450 (CYP) enzymes including CYP2D6, CYP3A, CYP2B6, and CYP2C19. The CYP genes are polymorphic resulting in variable enzyme activity. Retrospective clinical data suggests that specific single nucleotide polymorphisms (SNPs) of CYP2D6 can lead to null or reduced enzyme acti..