Combined aberrant expression of microRNA-214 and UBC9 is an independent unfavorable prognostic factor for patients with gliomas

microRNA-214 (miR-214) plays an important role in tumor cell proliferation, migration and invasion, as well as tumor angiogenesis. Ubiquitin-conjugating enzyme 9 (UBC9) is implicated in regulating several critical cancer-related pathways. Recent study has demonstrated that miR-214 reduction may facilitate UBC9 expression and may be involved in the regulation of glioma cell proliferation. The aim of this study was to clarify the clinical significance of miR-214 and UBC9 in human glioma, which has not been fully elucidated. Quantitative real-time polymerase chain reaction analysis was used to characterize the expression patterns of miR-214 and UBC9 mRNA in 108 glioma and 20 normal brain tissues. The associations of miR-214 and UBC9 mRNA expressions with clinicopathological factors and prognosis of glioma patients were also statistically analyzed. Compared with normal brain tissues, the expression levels of miR-214 and UBC9 mRNA in glioma tissues were significantly downregulated and upregulated, respectively (both P < 0.001). There was a negative correlation between miR-214 and UBC9 mRNA expression in glioma tissues (r = -0.61, P = 0.01). Additionally, the combined miR-214 downregulation and UBC9 upregulation (miR-214-low/UBC9-high) was significantly associated with advanced pathological grade (P = 0.008). Moreover, Kaplan-Meier survival and Cox regression analyses showed that the glioma patients with miR-214-low/UBC9-high expression had poorest overall survival (P < 0.001) and conjoined expression of miR-214-low/UBC9-high was an independent prognostic indicator of glioma (P = 0.01). Furthermore, subgroup analyses showed that miR-214-low/UBC9-high expression was significantly associated with poor overall survival in glioma patients with high pathological grades (for grade III-IV: P < 0.001). This prospective study offers the convincing evidence for the first time that miR-214 and its target gene UBC9 may contribute to the development and the clinical outcome of glioma, and are valuable prognostic factors for glioma patients. A combined detection of miR-214/UBC9 expression may benefit us in predicting the prognosis of patients with advanced gliomas.