Background: The presence of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) 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 ERalpha and ERbeta and to assess clinical significance of ERalpha and ERbeta expression in gastric cancer.
Methods: The expression level of ERalpha and ERbeta 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 ERalpha mRNA expression in gastric cancer tissues and match normal tissues had no statistically significant difference. The ERbeta mRNA level in normal tissues was significantly higher than that observed in gastric cancer tissues (P = 0.001). Neither ERalpha nor ERbeta mRNA expression levels had significant correlation with clinicopathologic parameters. Forty-eight of 211 (22.7%) gastric cancer tissues showed positive expression of ERalpha and ERbeta detected in gastric cancer. ERalpha-positive expression correlated with poorer overall survival (P = 0.014), as did the absence of ERbeta expression in patients with gastric cancer (P = 0.001). In multivariate analysis, the positive expression of ERalpha and the absence of ERbeta 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 ERalpha and ERbeta were expressed in both gastric cancer and corresponding normal tissues. ERalpha expression and the absence of ERbeta expression are associated with poor survival.