AIM:To investigate the expression of Popeye domain containing 3(Popdc3) and its correlation with clinicopathological features and prognosis of gastric cancer.METHODS:The method of immunohistochemistry was used to investigate the expression of Popdc3 in 306 cases of human gastric cancer and 84 noncancerous gastric tissues.Simultaneously,the relationship between Popdc3 expression and the survival of the patients was retrospectively analyzed.RESULTS:Popdc3 was detected in 72(85.71%) of 84 human nontumor mucosa.High expression of Popdc3 protein was detected in 78(25.49%) of 306 human gastric cancer cases,and low expression was detected in 228(74.51%).Low expression of Popdc3 correlated with depth of invasion(P < 0.0001),regional lymph nodes(P < 0.0001) and distant metastasis(P = 0.02),and tumor,nodes,metastasis(TNM) stages(P < 0.0001).On multivariate analysis,only the patient’s gender,regional lymph node metastasis,distant metastasis,TNM stages,and the expression of Popdc3 were independent prognostic factors in patients with gastric cancer.The Kaplan-Meier plot showed that low Popdc3 expression had a much more significant effect on the survival of those patients with early-stage tumors(χ 2 = 104.741,P < 0.0001),with a > 51.9% reduction in the three-year survival compared with high Popdc3 expression.In late stages,the difference was also significant(χ 2 = 5.930,P = 0.015),with a 32.6% reduction in the three-year survival.CONCLUSION:Reduced expression of Popdc3 may play a significant role in the carcinogenesis and progression of gastric cancer.Popdc3 may be an independent prognostic factor. AIM: To investigate the expression of Popeye domain containing 3 (Popdc3) and its correlation with clinicopathological features and prognosis of gastric cancer. METHODS: The method of immunohistochemistry was used to investigate the expression of Popdc3 in 306 cases of human gastric cancer and 84 noncancerous gastric tissues. Simultaneously, the relationship between Popdc3 expression and the survival of the patients was retrospectively analyzed. RESULTS: Popdc3 was detected in 72 (85.71%) of 84 human nontumor mucosa. High expression of Popdc3 protein was detected in 78 (25.49%) Of the 306 human gastric cancer cases, and low expression was detected in 228 (74.51%). Low expression of Popdc3 correlated with depth of invasion (P <0.0001), regional lymph nodes (P <0.0001) , and the tumor, nodes, metastasis (TNM) stages (P <0.0001) .On multivariate analysis, only the patient’s gender, regional lymph node metastasis, distant metastasis, TNM stages, and the expression of Popdc3 were independent prognostic factors in patients with gastric cancer. Kaplan-Meier plot showed that low Popdc3 expression had a much more significant effect on the survival of those patients with early-stage tumors (χ 2 = 104.741, P <0.0001) with a> 51.9 % reduction in the three-year survival compared with high Popdc3 expression. late stages, the difference was also significant (χ 2 = 5.930, P = 0.015), with a 32.6% reduction in the three-year survival. of Popdc3 may play a significant role in the carcinogenesis and progression of gastric cancer. Popdc3 may be an independent prognostic factor.