Upregulation of microRNA-224 confers a poor prognosis in glioma patients

MicroRNA-224 (miR-224) has been consistently reported to be dysregulated in various human malignancies and can potentially affect many cancer-related cellular processes, including transcription, cell differentiation, cell death, growth, and cell proliferation. However, its roles in human glioma have not been reported. The aim of this study was to explore the expression pattern, clinical significance, and prognostic value of miR-224 in glioma patients using large cohorts. Quantitative real-time polymerase chain reaction analysis was used to characterize the expression patterns of miR-224 in 108 glioma and 20 normal brain tissues. The associations of miR-224 expression with clinicopathological factors and prognosis of glioma patients were also statistically analyzed. miR-224 expression is significantly upregulated in glioma tissues compared with normal brain tissues (P < 0.001). In addition, high expression of miR-224 was significantly associated with advanced pathological grade (P = 0.006) and low Karnofsky performance score (KPS, P = 0.01). Moreover, Kaplan-Meier survival analysis showed that high miR-224 expression group had significantly shorter disease-free survival (DFS) and overall survival (OS) rates than low miR-224 expression group (both P < 0.001). Multivariate analysis with the Cox's proportional hazards model revealed that high expression of miR-224 (P = 0.006 and P = 0.01, respectively) and advanced pathological grade (both P = 0.02) were independent factors for shorter DFS and OS. Furthermore, subgroup analyses showed that miR-224 expression was significantly associated with poor DFS and OS in glioma patients with high pathological grades (for grade III-IV: P < 0.001 and P = 0.005, respectively). MiR-224 is upregulated and confers a poor prognosis in glioma patients.