Prognostic Role of Estrogen Receptor a and Estrogen Receptor β in Gastric Cancer

Background. The presence of estrogen receptor alpha (ER alpha) and estrogen receptor beta (ER beta) have been reported in cell and tissue level in gastric cancer, but its impact on patients' survival remains unclear. This study was designed to investigate the expression level of ER alpha and ER beta and to assess clinical significance of ER alpha and ER beta expression in gastric cancer. Methods. The expression level of ER alpha and ER beta were assessed by reverse-transcriptase polymerase chain reaction (RT-PCR) in 35 surgically resected gastric cancer and corresponding normal tissues and by immunohistochemical staining in 211 surgically resected gastric cancer and match normal tissues. Results. The expression level between ER alpha mRNA expression in gastric cancer tissues and match normal tissues had no statistically significant difference. The ER beta mRNA level in normal tissues was significantly higher than that observed in gastric cancer tissues (P = 0.001). Neither ER alpha nor ER beta mRNA expression levels had significant correlation with clinicopathologic parameters. Forty-eight of 211 (22.7%) gastric cancer tissues showed positive expression of ER alpha and ER beta detected in gastric cancer. ER alpha-positive expression correlated with poorer overall survival (P = 0.014), as did the absence of ER beta expression in patients with gastric cancer (P = 0.001). In multivariate analysis, the positive expression of ER alpha and the absence of ER beta were significant independent prognostic factors for overall survival (hazard ratio 2.159, P = 0.013, and hazard ratio 2.016, P = 0.025 respectively). Conclusions. Our results indicated that ER alpha and ER beta were expressed in both gastric cancer and corresponding normal tissues. ER alpha expression and the absence of ER beta expression are associated with poor survival.