MicroRNA-200b expression level is negatively associated with pathological grading in human gliomas

AIM: To elucidate the clinical implication of microRNA (miRNA)-200b in the pathological grading of gliomas. METHODS: We searched the Chinese National Knowledge Infrastructure, Web of Knowledge, Embase, and PubMed databases. Related articles were assessed, and ORs with 95% CIs were calculated to examine the relationship between miRNA-200b expression levels and the World Health Organization (WHO) glioma grade, patients’ sex and age, tumor size, and extent of surgical resection. Heterogeneity, publication bias, and stability of the pooled results of the included studies were also analyzed. MiR-200b expression in 87 human glioma tissues (50 high grade and 37 low grade) and matched 41 non-neoplastic brain tissues was measured by real-time quantitative RT-PCR assay. RESULTS: Five eligible studies involving 630 patients were included in the present meta-analysis. The miRNA-200b expression in glioma tissues was negatively associated with the WHO glioma grade (OR, 0.070; 95% CI, 0.007–0.678; P=0.022). No significant correlations were found between miRNA-200b and sex (P=0.858), age (P=0.776), tumor size (P=0.134), or extent of resection (P=0.778). In our own test, compared with non-neoplastic brain tissues, the expression level of miR-200b was significantly decreased in glioma tissues (tumor vs normal: 4.29±1.90 vs 10.45±2.34, P<0.001). In addition, we found that the glioma tissues from high-grade tumors (grade III and IV) had much lower miR-200b expression than glioma tissues from low grade tumors (grade I and II). CONCLUSION: Our results suggest that the miRNA-200 expression level may be negatively associated with the WHO glioma grade (malignancy). MiRNA-200 might serve as a prognostic and diagnostic biomarker or a helpful therapeutic target.