confirmed that in the gastric cancer microenvironment, tumors could up-regulate the expression of Forkhead transcription factor 3 (Foxp3) in tumor-infiltrating Treg cells and inhibit the proliferation of autologous CD4(+) CD25(−) T cells by producing COX-2/PGE (2) (158). This evidence concerns the gene PTGS2 and gastric cancer.