Related Experiment Video
Updated: May 18, 2026

A Method to Study the C924T Polymorphism of the Thromboxane A2 Receptor Gene
Published on: April 1, 2019
Laboratory testing of CYP2D6 alleles in relation to tamoxifen therapy
Elaine Lyon1, Julie Gastier Foster, Glenn E Palomaki
1Department of Pathology, University of Utah School of Medicine, Molecular Genetics, ARUP Laboratories, Salt Lake City, Utah, USA. lyone@aruplab.com
Abstract:
Tamoxifen, a widely prescribed drug for the treatment and prevention of breast cancer, is metabolized to more potent metabolites by the cytochrome P450 2D6 (CYP2D6) enzyme. Variants in the CYP2D6 gene can cause patients to be either intermediate or poor metabolizers, thereby rendering tamoxifen treatment less effective. Testing for CYP2D6 gene variants is available in Clinical Laboratory Improvement Amendments-certified clinical laboratories; however, the biological complexity of the variants makes result interpretation and phenotype prediction challenging. This article describes the clinical significance of variants as well as important analytical, interpretative, and reporting issues. It is designed to be a guideline for clinical laboratory professionals in performing tests and interpreting results with respect to CYP2D6 genetic variants.
Related Concept Videos
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Pharmacogenetics of Drug Metabolism: Overview
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Drug toxicity: Idiosyncratic Reactions
