Prognostic Role of MicroRNA-21 in Gastric Cancer: A Meta-Analysis

BACKGROUND: Mounting evidence shows that microRNAs may be useful as prognostic biomarkers of gastric cancer. The aim of this meta-analysis was to summarize the predictive role of miR-21 for survival in patients with gastric cancer and to verify the association between expression of miR-21 and clinical characteristics. MATERIAL/METHODS: All the eligible studies were searched by PubMed and EMBASE and clinical characteristics and survival results were extracted. Then a meta-analysis was carried out to clarify the prognostic role of the miR-21 expression in different subgroups. RESULTS: We included 8 studies dealing with gastric cancer in this meta-analysis. For overall survival, the pooled hazard ratio of higher miR-21 expression in tumor tissue was 2.00 (95% CI: 1.39–2.88, P<0.01), which could significantly predict poorer survival in gastric cancer patients. Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with tumor differentiation 0.42 (95% CI: 0.25–0.70 p<0.01), lymph node metastasis 6.39(95% CI: 3.11–13.14, P<0.01), and TNM stage 0.38 (95% CI: 0.21–0.67, P<0.01). CONCLUSIONS: This meta-analysis indicates that miR-21 detection has a prognostic value in patients with gastric cancer. In addition, overexpression of miR-21 is associated with worse tumor differentiation, lymph node metastasis, and TNM stage.