Impairment of endoxifen formation in tamoxifen-treated premenopausal breast cancer patients carrying reduced-function CYP2D6 alleles.

ABSTRACT:

Aims

Tamoxifen is bioactivated to endoxifen by polymorphic CYP2D6-dependent metabolism. Here, endoxifen levels were compared to CYP2D6 diplotypes, tentative target concentrations and side effects.

Methods

In total, 118 Swedish premenopausal breast cancer patients diagnosed 2006-2014, with on-going postoperative tamoxifen treatment January 2017, were included. Biobanked DNA from peripheral blood was used for CYP2D6 genotyping by TaqMan real-time polymerase chain reaction (CYP2D6*1, *3, *4, *5, *6, *9, *10, *41, *1xN). Plasma levels of tamoxifen and 3 major metabolites were quantified by liquid chromatography-tandem mass spectrometry. Clinical information on treatment and side effects was retrospectively obtained from medical records.

Results

In the final analysis of 11

SUBMITTER: Thoren L 

PROVIDER: S-EPMC9328423 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature