ESR1 and GPX1 genes expression level in human malignant and non-malignant breast tissues

Abstract

Background: The aim of this study was to find out whether the mRNA expression of estrogen receptor alpha (encoded by ESR1) correlates with the expression of glutathione peroxidase 1 (encoded by GPX1) in tumor and adjacent tumor-free breast tissue and whether this correlation is affected by breast cancer. Such relationships may give further insights into breast cancer pathology with respect to the status of estrogen receptor. Methods: We used the quantitative real-time PCR technique to analyze differences in the expression levels of the ESR1 and GPX1 genes in paired malignant and non-malignant tissues from breast cancer patients. Results: ESR1 and GPX1 expression levels were found to be significantly down-regulated by 14.7% and 7.4% (respectively) in the tumorous breast tissue compared to the non-malignant one. Down-regulation of these gene were independent of tumor histopathology classification and clinicopathological factors while ESR1 mRNA level was reduced with increasing tumor grade (G1: 103% vs. G2: 85.8% vs. G3: 84.5%; p<0.05). In the non-malignant and malignant breast tissues, the expression levels of ESR1 and GPX1 were significantly correlated with each other (Rs=0.450 and Rs=0.360; respectively). Conclusion: These data suggest that down-regulation of ESR1 and GPX1 are independent on clinicopathological factors. Down-regulation of ESR1 gene expression enhanced with the development of the disease. Moreover, GPX1 and ESR1 genes expression are interdependent in the malignant breast tissue and further work is needed to determine the mechanism underlying this relationship.