Purpose To investigate the expression of gelsolin-like actin-capping protein (CapG) in gastric cancer and adjacent normal gastric tissues and its relationship with clinicopathological features and prognosis.Methods The immunohistochemical (IHC) assay was performed to detect the expression of CapG protein in 125 specimens of gastric cancer (study group) and 30 specimens of matched adjacent normal gastric tissues (control group).No patients had received chemotherapy or radiotherapy before surgery.Immunostaining was scored semiquantitatively by two independent observers who were blinded to the patients' outcome and other clinicopathological parameters.The correlation of the expression of CapG with clinicopathological characteristics and prognosis was analyzed.Results Cytoplasmic and nuclear CapG protein staining was detected in all gastric cancer tissues.CapG protein expression was absent or low in matched adjacent normal gastric tissues but significantly higher in gastric cancer tissues.Expression of CapG in the tumor was not significantly associated with gender,age,tumor size,tumor location (P ＞ 0.05).However,elevated CapG expression was strongly correlated with the depth of invasion (P =0.044),lymph node metastasis (P =0.026),distant metastasis (P =0.001),and AJCC stage (P =0.012).Significant poorer overall survival was observed in the high CapG expression group compared with that of the low CapG expression group (P ＜0.001).Multivariate analysis showed overall survival correlated with the patients' tumor location,lymph node metastasis,distant metastasis,AJCC stage and the expression of CapG protein.Conclusion CapG is highly expressed in gastric cancer.Tumors with CapG up-regulation tend to have poorer prognosis,suggesting overexpression of CapG may contribute to the prediction of poorer prognosis and may be a potential therapeutic target for gastric cancer.