POLYMORPHISMS EVALUATION OF CYP2D6 IN PATIENTS WITH BREAST CANCER AND TAMOXIFEN USERS OF TWO BREAST SERVICES OF BELO HORIZONTE-BRAZIL.

Breast cancer (BC) is a heterogeneous and complex disease, comprising multiple forms of clinical and morphological presentation, with different degrees of tumor aggressiveness and metastatic potential. Treatment is multidisciplinary, being the use of tamoxifen (TAM) a consecrated important therapeutic modality. It is metabolized by the CYP2D6 enzyme in its active metabolites, 4 – hydroxytamoxifen (HTF) and endoxifen (EDF), which are up to 100 times more potent than TAM in suppressing the proliferation of estrogen dependent tumor cells. This study aimed to evaluate the polymorphism of CYP2D6*4 variant. Interview with 138 patients with BC treated with TAM was performed and also was collected blood samples for genotyping CYP2D6*4. Regarding the polymorphism, 81.15 % were extensive metabolizers (* 1 / * 1) 16.66% were intermediate metabolizers (* 1 / * 4) and 2.17% were poor metabolizers (* 4 / * 4). These data corroborate with the literature in relation to CYP2D6*4 polymorphism.