PURPOSE: We aimed to investigate the prevalence and prognostic impact of tumor mesenchymal epithelial transition factor (MET) expression in stage IV gastric cancers in a real-world clinical setting because existing evidence is sparse.

METHODS: The study included archived cancer specimens from 103 stage IV gastric cancer patients (2003-2010). We analyzed MET-protein expression by immunohistochemistry (MET-positive if ≥25% of tumor cells showed MET expression). We calculated overall survival using the Kaplan-Meier method and hazard ratios comparing mortality among MET-positive and MET-negative patients using Cox regression adjusted for age, gender, and comorbidity.

RESULTS: We found that 62.1% (95% confidence interval, 52.0-71.5) of patients had MET-positive tumors. Median survival was lower among patients with MET-positive tumors (3.5 months) than among patients with MET-negative tumors (9.6 months), corresponding to an adjusted hazard ratio of 2.2 (95% confidence interval, 1.3-3.7).

CONCLUSIONS: Tumor MET expression is prevalent and has substantial prognostic impact in stage IV gastric cancer patients.