High expression of meningioma 1 is correlated with reduced survival rates in colorectal cancer patients.

The identification of prognostic markers for colorectal cancer (CRC) has important clinical implications. However, the association between meningioma 1 (MN1) expression and clinical outcomes of CRC has not been fully investigated. The aim of this study was to investigate the expression of MN1 in the clinical context of CRC. We first used immunohistochemistry (IHC) staining to examine and compare MN1 expression between multiple human cancer tissues and normal tissues. Initial screening revealed that the expression of MN1 proteins was significantly higher in tumor tissues of the breast, colon, and liver than in normal tissues. In further testing conducted on 59 paired CRC samples, we observed that the expression of MN1 in CRC tissue samples was significantly higher than in adjacent normal tissues. Moreover, high MN1 expression was not significantly associated with clinicopathological characteristics. Kaplan-Meier survival analysis revealed that high expression of MN1 mRNA or MN1 protein was significantly associated with poor CRC prognosis. Furthermore, univariate Cox analysis revealed that a high MN1 score was significantly associated with prognostic factors. Multivariate Cox analysis further indicated that gender, histologic grade, tumor-node-metastasis (TNM) stage, and a high MN1 score were independent factors of overall CRC survival rates. Finally, MN1 and PCNA protein levels were positively correlated, which suggests that MN1 may be involved in the cell proliferation process during CRC formation. Our results, which confirm those of other studies, indicate that (1) high levels of MN1 expression contribute to poor CRC prognosis and (2) MN1 can serve as a novel potential biomarker in predicting the prognosis of CRC patients.