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Abstract LB-139: The effects and mechanisms of TNF-α/TNFR2 in regulatory T cells on microenvironment and progression in gastric cancer

Background: Regulatory T cells (Tregs) are potent immunosuppressive cells of the immune system. They facilitate the survival and progression of tumor through their ability to suppress the antitumor immunity. The expression of tumor necrosis factor receptor type II (TNFR2) on Tregs is reported to identify the maximally suppressive Treg population in both mice and human. According to our previous research, expression of TNFR2 appeared to correlate better than CD25+ and CD127− with FoxP3 expression. Aim: The effects and mechanisms of TNF-α/TNFR2 in regulatory T cells on microenvironment and progression in gastric cancer are needed to be studied. Methods: The expression and phenotype of TNFR2 + Tregs in peripheral blood and tumor tissues of 33 cases of gastric cancer patients and in peripheral blood of 15 normal controls were detected by flow cytometry. The ratio of Foxp3+Tregs and TNFR2+Tregs of 145 cases of gastric cancer patients was analyzed by multicolor immunofluorescence assay. We analyzed their relationship with gastric cancer stage, metastasis and other clinical indicators by clinical and pathological data. Results: Flow cytometry showed that the expression of TNFR2 in human peripheral blood Tregs was significantly higher than that in conventional T cells (Tconvs) in peripheral blood CD4 + T cell subsets of gastric cancer patients and healthy individuals (P Conclusion: Our findings revealed that TNFR2 could be a promising molecular marker associated with poor prognosis. The mechanism by which TNFR2+Tregs promote tumor survival and progression in gastric cancer is still needed further research. Citation Format: Yang Qu, Gang Zhao, Hui Li. The effects and mechanisms of TNF-α/TNFR2 in regulatory T cells on microenvironment and progression in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-139.