CYP2D6*4 polymorphisms and breast cancer risk
CYP2D6 gene plays an important role in detoxification of many drugs and plays a crucial role in the metabolism of tamoxifen, used in endocrine therapy. In the present study, the heterozygous frequency IM (40.8%) was significantly increased in breast cancer patients when compared to controls. When the data on IM and PM were pooled, significant increase in the frequency of pooled genotype in disease group (42.4%) was observed as compared to controls (27.6%). The frequency of IM genotype was found to be increased in women with premenopausal breast cancer patients (43.5%) and patients with familial history of cancer (43.2%). Higher frequency of IM as well as pooled genotypes PM+IM was found in cases with higher BMI and in patients occupied in agriculture (55.6%), patients positive for estrogen receptor (47.8%), progesterone receptor (44.8%), HER2/neu (26.9%) and advanced stage. Our results suggested that the CYP2D6*4 polymorphism plays an important role in the breast cancer etiology and might help in planning hormonal therapy where tamoxifen is used.