Expression and prognostic value of estrogen receptor beta in breast cancer patients

This study is to determine the expression of estrogen receptor beta (ERβ) in breast cancer patients and to evaluate its relationship with clinicopathological parameters of breast cancer and its effects on the prognosis of breast cancer patients. Paraffin-embedded primary tumor tissue sections from 490 breast cancer patients were collected consecutively from January 2000 to December 2010. They had complete clinical data and follow-up records. Immunohistochemical staining was conducted to determine ERβ expression. The Kaplan-Meier method was used for survival analysis. Difference in survival was analyzed by the Log-Rank test. The Cox proportional hazard model was performed to evaluate the prognostic value of ERβ expression in breast cancer patients. The ERβ high and over expression rate in 490 breast patients was 22.4% (110/490). ERβ expression was not associated with clinicopathological parameters of breast cancer. The mean survival time in patients with ERβ negative expression, ERβ low expression, ERβ high expression and ERβ over expression was 9.9 years, 9.2 years, 8.6 years and 5.6 years. Statistically, patients with ERβ high and over expression had significantly shorter disease-free survival (DFS) time compared with the patients with ERβ negative and low expression. The Cox multivariate analysis revealed that ERβ high and over expression, the pathologic stages of tumor and chemotherapy were the independent predictors for poor DFS in breast cancer patients. ERβ expression is an independent prognostic factor of breast cancer patients and its high and over expression indicates poor prognosis of breast cancer. There was no correlation between ERβ expression and clinicopathological parameters in breast cancer.