C-Met as a potential novel prognostic marker in squamous cell carcinoma and adenocarcinoma of esophagus: evidence from a meta-analysis

INTRODUCTION. The prognostic value of c-Met in patients with esophageal cancer (EC) remains inconsistent and controversial. Our study aims to clarify the correlation between c-Met overexpression and clinical outcome in EC patients. EVIDENCE ACQUISITION. We performed a comprehensive search of EMBASE, PubMed, Web of Science, Chinese National Knowledge Infrastructure (CNKI) and Chinese Biomedical Database (CBM) (from inception to May 1, 2016) for published literature regarding the potential association between c-Met overexpression and clinical outcome in EC patients. A fixed-effects or random-effects model according to heterogeneity was applied to calculate the pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS), disease-free survival (DFS) and disease-specific survival (DSS). EVIDENCE SYNTHESIS. Nine eligible studies totaling 1062 patients were identified in this meta-analysis. C-Met overexpression was significantly associated with shorter OS (HR: 2.04, 95% CI: 1.66-2.52, P<0.001) and DSS (HR: 3.03, 95% CI: 2.04-4.48, P<0.001) in patients with EC. However, no significant relationship between high expression of c-Met and DFS that was found (HR: 1.81, 95% CI: 0.77-4.26, P=0.176). For OS, similar associations were demonstrated in either esophageal squamous cell carcinoma (ESCC) (HR: 2.17, 95% CI: 1.62-2.90, P<0.001) or esophageal adenocarcinoma (EAC) (HR: 1.92, 95% CI: 1.42-2.59, P<0.001). Additionally, further subgroup analyses according to publication year, ethnicity, the sample size, and statistical methodology all revealed a significant association between high expression of c-Met and OS in patients with EC. CONCLUSIONS. The current evidence indicated that c-Met overexpression is significantly associated with a poorer prognosis in EC. C-Met may serve as a potential novel prognostic biomarker for EC patients.