摘要Background FOXP3 was thought to express in the T-cell lineage exclusively until recently when FOXP3 was shown to be expressed by cancer cells. It was indicated that FOXP3 may play a wider role in biology by endowing tumor cells with immune suppressive activity. However, researches between FOXP3 and lymph node metastasis of gastric cancer were relatively infrequent, so the present work was aimed to investigate the relationship between FOXP3 expression and lymph node metastasis in human gastric cancer.Methods A total of 122 gastric cancer patients were enrolled in this study, and gastric tumor specimens and lymph nodes were acquired. Thirty patients who had chronic superficial gastritis diagnosed by gastroscopy contemporaneously in the Peking University People's Hospital were chosen randomly as the control group. Immunohistochemistry was performed to evaluate FOXP3 expression. A survival analysis on the 122 patients was then performed. Then, NCI-N87cell lines were used to confirm FOXP3 expression in gastric carcinoma cells. Finally, evaluation of FOXP3 expression in gastric tumor and peritumor tissues in 12 patients were conducted using immunohistochemistry and Western blotting. A X2 test or Fisher's exact test (bilateral) was conducted to compare the percentage of positive percentage staining between groups. Kaplan-Meier analysis was performed for survival analysis.Results FOXP3 was expressed by gastric cancer cells and peritumor epithelial cells. FOXP3 expression was increased in primary tumors (58.2%) than that in control group (26.7%). In the lymph-node metastasis group, the incidence of lymph node metastasis which was less than 60% had a significant upregulation of FOXP3 in primary tumors and lymph nodes.However, the frequency of FOXP3 expression had no relationship with survival.Conclusion FOXP3 probably has a relationship with lymph node metastasis of gastric cancer.