Association of the oestrogen receptor beta with hormone status and prognosis in a cohort of female patients with colorectal cancer

Background The oestrogen receptor beta (ERβ) is the predominant oestrogen receptor in the normal colon mucosa and has been reported to exert anti-proliferative and pro-apoptotic effects. However, the role of ERβ in colorectal cancer (CRC) progression remains unclear. Aim To investigate the role of ERβ and its association with hormone status and lifestyle indicators in a female cohort of patients with CRC. Methods Tissue microarrays of primary CRC tumour samples from 320 female patients were conducted with a monoclonal anti-ERβ antibody. The staining intensity was evaluated using immunohistochemistry. The association of ERβ expression with overall survival, disease-free survival, hormone status and lifestyle was evaluated, and effect estimators with 95% confidence intervals (CIs) were reported. Results Among the 314 samples with successfully detected ERβ, 182 (58%) had low expression and 132 (42%) had high expression. The Cox multivariate analysis indicated that patients with high ERβ expression had a decreased risk of overall mortality by 50% (hazard ratio [HR], 0.50; CI, 0.30–0.83) and of cancer recurrence by 76% (HR, 0.24; CI, 0.11–0.52) after adjusting for age, tumour-node-metastasis stage and tumour intravascular invasion. Furthermore, high ERβ expression was significantly correlated with shorter breastfeeding time and longer use of hormone replacement therapy. No association was found between ERβ expression and lifestyle indicators. Conclusion Elevated ERβ expression is independently associated with a better prognosis and hormone status but not lifestyle indicators in female CRC patients