High expression of estrogen-related receptor α is significantly associated with poor prognosis in patients with colorectal cancer

Colorectal cancer (CRC) is one of the most common types of malignancy with high morbidity and mortality rates worldwide. This biologically heterogeneous disease results in diverse therapeutic responses, thus, novel prognostic biomarkers are required to improve CRC treatment. Estrogen-related receptor a (ERR alpha) is a nuclear orphan receptor, which is associated with estrogen receptor a. The present study aimed to investigate the expression of ERR alpha in patients with CRC, and explore the association between ERR alpha expression and clinicopathological factors, local recurrence and prognosis. In the present study, ERR alpha expression was detected in 15 fresh CRC tissues using quantitative real-time polymerase chain reaction (RT-qPCR) and in 128 paraffin-embedded CRC tissues using immunohistochemistry. The associations between ERR alpha expression and prognosis of CRC patients were evaluated by univariate, and multivariate (Cox proportional hazards model) analysis. RT-qPCR demonstrated that the mRNA expression of ERR alpha in CRC tissues was significantly higher compared with that in matched normal tissues. Immunohistochemistry revealed that ERR alpha high expression was detected in the nuclei of cancer cells from 39.1% (50/128) of CRC tissues. ERR alpha expression based on immunohistochemical staining was significantly associated with tumor differentiation, tumor invasion, lymph node status and Dukes stage (all P<0.05). Furthermore, patients with high ERR alpha expression were significantly associated with an increased risk of recurrence and poor prognosis, compared with patients with low ERR alpha expression. ERR alpha expression was identified as an independent prognostic factor for patients with CRC. In conclusion, ERR alpha serves important roles in the progression of CRC and is a potential prognostic factor for patients with CRC.