The Role of ESR1 Gene Polymorphic Markers in the Development of Breast Cancer and Resistance to Tamoxifen Therapy.

We studied the effect of functionally significant polymorphic markers of the ESR1 gene on the risk of breast cancer, tamoxifen resistance, and survival of patients with this type of cancer. The study included 239 primary breast cancer patients without distant metastases. The analysis of genotype frequency distribution for the studied ESR1 gene polymorphic markers showed the association of the rs2228480 and rs2234693 markers with tamoxifen resistance in the group of patients with luminal B type breast cancer. An association of these two polymorphic markers with the risk of tumor development was also revealed; for rs2234693 polymorphic marker, a relationship with the survival of patients was also showed.