AIM: To assess the correlation between decreased Muc5 AC expression and patients’ survival and clinicopathological characteristics by conducting a metaanalysis.METHODS: Literature searches were performed in Pub Med and EMBASE,and 11 studies met our criteria. Summary hazard ratios or odds ratios(ORs) with 95% confidence intervals(CIs) were calculated to estimate the effect. For the pooled analysis of the correlation between decreased Muc5 AC expression and clinicopathological characteristics(tumour invasion depth,lymph node metastasis,tumour-node-metastasis stage,tumour size,venous invasion and lymphatic invasion),ORs and their variance were combined to estimate the effect. RESULTS: Eleven retrospective cohort studies comprising 2135 patients were included to assess the association between Muc5 AC expression and overall survival and/or clinicopathological characteristics. Decreased Muc5 AC expression was significantly correlated with poor overall survival of gastric cancer patients(pooled HR = 1.35,95%CI: 1.08-1.7). Moreover,decreased Muc5 AC expression was also significantly associated with tumour invasion depth(pooled OR =2.12,95%CI: 1.56-2.87) and lymph node metastasis(pooled OR = 1.56,95%CI: 1.00-2.44) in gastric cancer.CONCLUSION: Decreased Muc5 AC expression might be a poor prognostic predictor for gastric cancer. AIM: To assess the correlation between decreased Muc5 AC expression and patients’ survival and clinicopathological characteristics by conducting a metaanalysis. METHODS: Literature searches were performed in Pub Med and EMBASE, and 11 studies with our criteria. Summary hazard ratios or odds ratios (ORs For the pooled analysis of the correlation between decreased Muc5 AC expression and clinicopathological characteristics (tumor invasion depth, lymph node metastasis, tumor-node-metastasis stage, tumor size, ORs and their variance were combined to estimate the effect. RESULTS: Eleven retrospective cohort studies comprising 2135 patients were included to assess the association between Muc5 AC expression and overall survival and / or clinicopathological characteristics. Decreased Muc5 AC expression was significantly correlated with poor overall survival of gastric cancer patients (pool (pooled OR = 2.12, 95% CI: 1.56-2.87) and lymph node metastasis (pooled OR = 2.12, 95% CI: 1.08-1.7). Moreover, decreased Muc5 AC expression was also significantly associated with tumor invasion depth 1.56, 95% CI: 1.00-2.44) in gastric cancer. CONCLUSION: Decreased Muc5 AC expression might be a poor prognostic predictor for gastric cancer.