Prognostic significance of MiR-34a in solid tumors: A systemic review and meta-analysis with 4030 patients

Purpose: The aim of the present meta-analysis and systematic review was to explore the association between the expression of miR-34a and prognosis in solid tumor. Methods: PubMed, Google Scholar, Web of Science and NCBI databases were used to search studies to evaluate the effect of miR-34a expression on clinical outcomes, including overall survival (OS), recurrence-free survival (RFS), disease-free survival (DFS), progression-free survival (PFS) and event-free survival (EFS) in solid tumor. The pooled random effect models were performed to calculate pooled hazard ratio (HR), 95% confidence interval (CI) to assess the association. Results: Twenty-three eligible studies with 4030 patients were included in this meta-analysis. It was confirmed that increased expression of miR-34a was in relevant with better DFS/RFS/PFS/EFS, which was identified with both univariate and multivariate models (univariate model: HR = 0.62, 95% CI: 0.42-0.92, P = 0.019; multivariate model: HR = 0.55, 95% CI: 0.34-0.88, P = 0.013). Furthermore, in the analysis of relationship between miR-34a and DFS/RFS/PFS/EFS, the results remained similar when excluding the studies contributed to the heterogeneity (univariate analysis: HR = 0.57, 95% CI: 0.46-0.70, P < 0.001; multivariate analysis: HR = 0.57, 95% CI: 0.43-0.75, P < 0.001). With univariate analysis, it was also demonstrated that miR-34a overexpression might be positively associated with a favorable OS in solid tumor (HR = 0.73, 95% CI: 0.54-1.00, P = 0.005) with considering an obvious heterogeneity. Conclusion: Our current study supports the notion that miR-34a may be a potential biomarker to predict OS and RFS/PFS/DFS/EFS in solid tumor.