Prognostic Value of Expression of MicroRNAs in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Background: microRNAs are widely involved in a variety of life processes and considered as potential biomarkers of tumor prognosis. A growing number of studies have documented that miRNAs were associated with outcome in NSCLC patients and can act as a prognostic marker. However, existing studies concerning the relationship between miRNAs and outcome in NSCLC patients were contentious and dispersive. Therefore, a systematic meta analysis to explore the prognostic value of miRNAs on NSCLC patients is urgently needed. Methods: Electronic databases, including PubMed, EMBASE, and Web of Science were searched for all relevant articles. Only articles investigating the survival effect of microRNAs on NSCLC patients were included in this meta-analysis. Hazard ratios (HRs) with 95% confidence interval (CI) were extracted and pooled on overall survival (OS) and progression free survival (PFS)/disease-specific survival (DSS). Results: 28 articles were finally included in the overall meta-analysis. The pooled results revealed that high expression miR-21 (HR = 2.82, 95% CI: 2.10 - 3.79), miR-200c (HR = 2.05, 95% CI: 1.36 - 3.07), and miR-125b (HR = 1.72, 95% CI: 1.30 - 2.28) were negatively associated with survival in NSCLC patients. Conversely, high expression miR-148b (HR = 0.37, 95% CI: 0.19 - 0.70), miR-365 (HR = 0.40, 95% CI: 0.27 - 0.59), miR-124 (HR = 0.29, 95% CI: 0.16 - 0.53), miR-32 (HR = 0.46, 95% CI: 0.33 - 0.65), miR-146a (HR = 0.35, 95% CI: 0.18 - 0.68), and miR-375 (HR = 0.66, 95% CI: 0.45 - 0.96) were significantly associated with better prognosis. Meanwhile, the expression of miR-93 (HR = 1.19, 95% CI: 0.38 - 3.69) and miR-126 (HR = 0.38, 95% CI: 0.12 - 1.16) showed no relationship with NSCLC prognosis. Conclusions: Our meta-analysis provided the evidence that miR-21, miR-200c, miR-125b, miR-148b, miR-365, miR-124, miR-32, miR-146a, and miR-375 can act as prognostic biomarkers in NSCLC.