Perspectives of pharmacogenetics approach to personalized tamoxifen therapy

Tamoxifen is the selective modulator of estrogen receptors. Nowadays, it is widely used in the treatment of ER(+) breast cancer and substantially decreases the risks of recurrence and disease progression. However, high interindividual variability in response is observed, calling for a personalized approach to tamoxifen treatment. Tamoxifen is metabolized by cytochrome P450, resulting in the formation of active metabolites, including 4-hydroxy-tamoxifen and endoxifen. The effectiveness and success of treatment depends largely on concentrations of the active tamoxifen metabolites in blood plasma. Polymorphisms in the genes encoding these enzymes are proposed to influence on pharmacokinetics and pharmacodynamics of tamoxifen. Therefore, pharmacogenetic approach may form the basis of personalized treatment of breast cancer. In this systematic review, we analyze all current data about the potential use of genotyping of CYP2D6, CYP3A4/5, CYP2B6 to predict an individual response on tamoxifen treatment.

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