CYP2D6 and tamoxifen: DNA matters in breast cancer

Tamoxifen is the most widely used anti-oestrogen for the treatment of hormone-dependent breast cancer. The pharmacological activity of tamoxifen is dependent on its conversion by the hepatic drug-metabolizing enzyme cytochrome P450 2D6 (CYP2D6) to its abundant metabolite, endoxifen. Patients with reduced CYP2D6 activity, as a