Expression of estrogen receptor beta wild-type and its variant ERbetacx/beta2 is correlated with better prognosis in breast cancer

Abstract

Background: The clinical value of estrogen receptor (ER) beta and its variants has been investigated. However, reported results have frequently been discordant.

Methods: We investigated mRNA and protein expression of ERbeta wild type (ERbeta1) and its variant, ERbetacx/beta2, by quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry in 150 breast cancer tissues, and analyzed association between their expression and clinicopathological factors and prognosis.

Results: ERbeta1 mRNA expression was significantly correlated with progesterone receptor expression and low histological grade. ERbeta1 protein expression was significantly correlated with small tumor size, negative lymph node status and low histological grade. ERbetacx/beta2 protein expression was significantly correlated with ERalpha expression and low histological grade. Patients with high expression of ERbeta1 or ERbetacx/beta2 had a significantly better disease-free and overall survival than those with low expression. In multivariate analysis, ERbetacx/beta2 mRNA expression was identified as a prognostic factor in disease-free and overall survival.

Conclusion: Our results indicate that ERbetacx/beta2 mRNA expression is an independent prognostic factor in breast cancer. ERbeta expression status, both wild-type and the variant cx/beta2, might represent significant predictors of breast cancer prognosis.