Downregulation of microRNA-124 is an independent prognostic factor in patients with colorectal cancer.

PURPOSE: Recently, microRNA-124 (miR-124) has been demonstrated as a potential tumor suppressor in several types of cancers. However, the role of miR-124 in colorectal cancer remains unclear. This study was aimed at investigating the clinicopathological significance of miR-124 expression in colorectal cancer. METHODS: Quantitative real-time PCR was used to analyze miR-124 expression in 96 colorectal cancers and individual-matched normal mucosa samples. The expression of miR-124 was assessed for associations with clinicopathological characteristics using chi-square test. The survival curves were calculated by the Kaplan-Meier method. The influence of each variable on survival was examined by the Cox multivariate regression analysis. RESULTS: The miR-124 expression was significantly downregulated in colorectal cancer compared to normal mucosa (P = 0.001). In colorectal cancer, miR-124 decreased expression correlated significantly with the grade of differentiation (P = 0.021). Univariate survival analysis showed that the downregulated miR-124 was significantly correlated with worse prognosis, both in terms of overall survival (P = 0.017) and disease-free survival (DFS) (P = 0.014). Further, the downregulated miR-124 was demonstrated as a prognostic factor for overall survival (hazard ratio, HR = 4.634; 95 % confidence interval, CI, 1.731-12.404; P = 0.002) and DFS (HR = 4.533, 95 % CI 1.733-11.856, P = 0.002), independently of gender, age, location, maximum tumor size, depth of invasion, differentiation, and TNM stage. CONCLUSIONS: MiR-124 may play a certain role in the development of colorectal cancer. The downregulation expression of miR-124 is an independent prognostic factor in patients with colorectal cancer.