Association of TNF-α and TNF-β gene polymorphism with steroid receptor expression in breast cancer patients

The presence of estrogen and progesterone receptors is correlated with good prognosis in breast cancer. The effect of TNF-alpha on down-regulation of estrogen receptor and blocking the proliferative response of breast cancer cells to estradiol have been demonstrated. However, the effect of TNFA and TNFB gene polymorphisms on the expression of steroid receptors in breast cancer cells is not well documented. Therefore, 160 breast cancer patients were recruited to investigate the association of TNFA and TNFB gene polymorphism with the level of steroid receptor expression. This association was not found to be significant for TNFA polymorphism and estrogen receptor expression (p = 0.07). However, when combined genotypes of TNFA and TNFB polymorphism was considered, homozygous patients for lower TNF-alpha producer genotypes (TNFA1/A1 and TNFB1/B1) showed significantly higher progesterone receptor expression (p = 0.041). Our findings indicate that TNFA and TNFB polymorphisms may be associated with the levels of steroid receptor expression in breast cancer patients. Further studies on a larger group of breast cancer patients are recommended.