Tamoxifen is a prodrug, and it is converted in part by cytochrome P450 2D6 (CYP2D6)−mediated oxidation into its most active metabolite, endoxifen. OncologySTAT: Would you describe the results of your work surrounding the pharmacogenetics of tamoxifen biotransformation and CYP2D6 metabolism? Why is this clinically relevant?Dr. Goetz: Endoxifen is the most abundant, active metabolite of tamoxifen.1 A key question is whether genetic and drug-induced variability in the CYP2D6 enzyme (and other enzymes...