Expression of microRNA-218 and its Clinicopathological and Prognostic Significance in Human Glioma Cases

Background: MicroRNAs are a class of noncoding RNAs which regulate multiple cellular processes duringtumor development. The purpose of this report is to investigate the clinicopathological and prognostic significanceof miR-218 in human gliomas. Materials and
Methods: Quantitative RT-PCR (qRT-PCR) was conducted todetect the expression of miR-218 in primary normal human astrocytes, three glioma cell lines and 98 pairedglioma and adjacent normal brain tissues.Associations of miR-218 with clinicopathological variables of gliomapatients were statistically analyzed. Finally, a survival analysis was performed using the Kaplan-Meier methodand Cox’s proportional hazards model.
Results: The expression level of miR-218 in primary normal humanastrocytes was significantly higher than that in glioma cell lines (p<0.01). Also, the expression level of miR-218in glioma tissues was significantly downregulated in comparison with that in the adjacent normal brain tissues(p<0.001). Statistical analyses demonstrated that low miR-218 expression was closely associated with advancedWHO grade (p=0.002) and low Karnofsky performance score (p=0.010) of glioma patients. Kaplan-Meier analysiswith the log-rank test showed that patients with low-miR-218 expression had poorer disease-free survival andoverall survival (p=0.0045 and 0.0124, respectively). Multivariate analysis revealed that miR-218 expressionwas independently associated with the disease-free survival (p=0.009) and overall survival (p=0.004) of gliomapatients.
Conclusions: Our results indicate that miR-218 is downregulated in gliomas and that its status mightbe a potential valuable biomarker for glioma patients.