Wen-Li Jiang,1 Peng-Fei Zhang,2 Guo-Feng Li,1 Jian-Hua Dong,1 Xue-Song Wang,1 Yuan-Yu Wang3 1Department of Surgery, Juxian People’s Hospital, 2Department of Surgery, Rizhao People’s Hospital of Traditional Chinese Medicine, Rizhao, 3Department of Gastrointestinal Surgery, Zhejiang Provincial People’s Hospital, Hangzhou, People’s Republic of China Aim: To investigate the clinical significance of Oct-4 in the development and progression of gastric cancer.Methods: Immunohistochemistry was used to analyze Oct-4 expression in 412 gastric cancer cases. Oct-4 protein levels were upregulated in gastric cancer tissues compared with adjacent noncancerous tissues.Results: Positive expression of Oct-4 correlated with age, depth of invasion, Lauren classification, lymph node metastasis, distant metastasis, and TNM stage. In stages I, II, and III, the 5-year survival rate of patients with high expression of Oct-4 was significantly lower than that in patients with low expression of Oct-4. In stage IV, Oct-4 expression did not correlate with the 5-year survival rate. Furthermore, multivariate analysis suggested that the depth of invasion, lymph node metastasis, distant metastasis, TNM stage, and upregulation of Oct-4 were independent prognostic factors of gastric cancer.Conclusion: Oct-4 protein is a useful marker in predicting tumor progression and prognosis. Keywords: gastric carcinoma, invasion, metastasis, survival rate