Preventive Treatment with PD-1 Antibody Increases Tissue-resident Memory T Cells Infiltration and Delays Esophageal Carcinogenesis.

Numerous studies and clinical trials have shown that immune checkpoint inhibitors can effectively prevent tumor growth and metastasis in esophageal squamous cell carcinoma (ESCC) patients. In this study, we aimed to evaluate the anti-tumor effects of PD-1 antibody preventive treatment in patients with early stages ESCC as well as patients with high-grade intraepithelial neoplasia (HGIN). We first established an ESCC model using C57BL/6J mice treated with the chemical carcinogen 4- NQO and observed esophageal lesions at different time points. Second, we compared the antitumor efficacy of PD-1 antibody treatment in mice at the ESCC stage and PD-1 antibody preventive treatment in mice at the HGIN stage. The results showed that PD-1 antibody preventive treatment effectively impeded the progression of 4NQO-induced esophageal tumorigenesis. IHC analysis was performed to observe the infiltration of immune cells into the tumor microenvironment. It has been shown that active tissue-resident memory T cells can be induced and resided into the tumor microenvironment for a long period after treatment with PD-1 antibody. Reexposure to the oncogenic environment colonized by CD8+TRM cells can still exert antitumor effects. These results provide new strategies for the treatment of patients with early stage ESCC and HGIN. PREVENTION RELEVANCE: Immune checkpoint inhibitors have shown promising results in multiple tumor species. However, there is currently no clinical application to evaluate their therapeutic value in cancer preventive treatment. Prophylactic use of immune checkpoint inhibitors in the early stages of ESCC may provide long-term benefits to patients.