MicroRNA-15a down-regulation is associated with adverse prognosis in human glioma.

OBJECTIVE: The aim of this study was to investigate whether miR-15a has prognostic relevance in human gliomas.

METHODS: The expression levels of miR-15a were analyzed in glioma surgical resection tissues by microarray and quantitative real-time PCR. Survival analysis by the Kaplan-Meier method was performed to assess prognostic significance.

RESULTS: Downregulation of miR-15a was detected in most primary gliomas, which was confirmed by qRT-PCR analysis. Additionally, the down-regulation of miR-15a was significantly associated with the WHO grade (P = 0.003), the low KPS (P = 0.027), time to recurrence (P = 0.044) and the poor OS (P = 0.046). Using Kaplan-Meier analysis, a comparison of survival curves of low versus high expresser of miR-15a revealed a highly significant difference in OS (P = 0.001) and DFS (P = 0.006), which suggested that low expression of miR-15a is associated with a worse prognosis. Multivariate analyses showed that miR-15a expression was independent risk factors predicting OS [Hazard ratio (HR), 7.52; 95 % confidence interval (CI), 2.63-21.47; P = 0.002] and DFS [HR, 11.56; 95 % CI, 5.17-25.96; P < 0.001] in glioma.

CONCLUSIONS: These findings indicated for the first time that the expression of miR-15a is significantly correlated with prognosis in glioma patients, suggesting that the miR-15a may serve as independent prognostic marker.