Prognostic value of the microRNA-214 in multiple human cancers: a meta-analysis of observational studies

Previous studies showed that microRNA-214 (miR-214) may act as a prognostic biomarker of cancer. However, the available evidence is controversial. This study summarizes evidence and evaluates the prognostic role of miR-214 in various cancers. We carried out a systematic literature review and assessed the quality of included studies based on Oxford Centre for Evidence-based Medicine Criteria and Newcastle-Ottawa Scale (NOS). Pooled hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) for overall survival (OS) and disease free survival/progressive free survival/recurrence free survival (DFS/PFS/RFS) were calculated to measure the effective value of miR-214 expression on prognosis. Thirteen studies were included in pooled analysis. We found that miR-214 was significantly correlated with OS (HR=2.21, 95%CI: 1.33-3.68, P=0.00), no significant difference was found with DFS/PFS/RFS (HR=1.73, 95%CI: 0.78-3.83, P=0.18) in various carcinomas. In subgroup analysis, higher expression of miR-214 was significantly associated with poor OS in Asians (HR=2.27, 95%CI: 1.09-4.73, P=0.00) and Caucasians (HR=2.04, 95%CI: 1.47-3.30, P=0.00). On the contrary, high miR-214 expression significantly predicted favorable DFS/PFS/RFS (HR=0.50, 95%CI: 0.31-0.82, P=0.00) in hepatocellular carcinoma (HCC) group. Our data indicates that high miR-214 could be a promising biomarker for prognosis prediction of cancer. However, further clinical studies are needed for the current insufficient relevant data.