miR-218 tissue expression level is associated with aggressive progression of gastric cancer.

The aim of the present study was to investigate the clinical significance of microRNA-218 (miR-218) in gastric cancer. We enrolled 112 patients having undergone surgery for gastric cancer between May 2008 and June 2014. Expression of miR-218 was determined by real-time quantitative reverse transcription-polymerase chain reaction. Survival curves were plotted using the Kaplan-Meier method and compared by the log-rank test. We found that miR-218 expression was significantly downregulated in gastric cancer tissues compared to adjacent normal tissues (P < 0.001). Low miR-218 expression was significantly associated with tumor differentiation (P < 0.001), depth of tumor invasion (P = 0.006), and tumor node metastasis stage (P < 0.001). Kaplan-Meier survival analysis revealed that patients with low miR-218 levels showed significantly lower 5-year overall survival than those demonstrating high expression (P = 0.04). Multivariate Cox regression analyses indicated that low miR-218 expression constitutes an independent molecular biomarker for prediction of poor overall survival of gastric cancer patients (hazard ratio = 3.187, 95% confidence interval = 1.551-8.365, P = 0.037). In conclusion, miR-218 was remarkably downregulated in gastric cancer tissues and may serve as a prognostic biomarker for patients suffering from this disease.