Acmg Standards and Guidelines

introduction Laboratories are beginning to offer pharmacogenetics assays in support of continuing efforts toward more personalized medicine. In patients with breast cancer for whom treatment with tamoxifen is being considered, the clinical validity of CYP2D6 genotyping is not well established. Nonetheless, the results may be helpful in identifying patients who will not respond well to the treatment. This article is intended to help clinical laboratory personnel who are offering or intending to offer CYP2D6 genotyping in patients for whom tamoxifen therapy is being considered. The compound tamoxifen belongs to the class of drugs known as selective estrogen receptor modulators. Our focus here is on laboratory implementation including analytical and clinical validity, available platforms, challenges in the interpretation and reporting of complex test results, and the potential for clinical utility. Clinical CYP2D6 genotyping can also be ordered in the context of other drugs and potential adverse outcomes (e.g., antidepressants, antipsychotics, and codeine). However, a detailed description of implementing CYP2D6 genotyping for these other medications falls outside the scope of this article.