The Immunological Impact of Neoadjuvant Chemotherapy on the Tumor Microenvironment of Esophageal Squamous Cell Carcinoma

Abstract

Esophageal cancer is an aggressive cancer with poor prognosis. However, little is known about the immune response in the tumor microenvironment after neoadjuvant chemotherapy.To investigate the immunological impact of neoadjuvant chemotherapy in the tumor microenvironment of esophageal squamous cell carcinoma.Eighteen patients with esophageal squamous cell carcinoma with and without neoadjuvant chemotherapy were analyzed using immunohistochemical methods for human leukocyte antigen (HLA) class I heavy chain, CD4-, CD8-, and Foxp3-positive cell infiltration.The number of CD4 T cells in the stroma and within the cancer nest was significantly higher in the neoadjuvant chemotherapy group. The number of CD8 T cells in the stroma was significantly higher in the neoadjuvant chemotherapy group. HLA class I expression was more downregulated in the control group compared with the neoadjuvant chemotherapy group.Neoadjuvant chemotherapy utilizing 5-fluorouracil and cisplatin in esophageal squamous cell carcinoma is useful to induce CD4 and CD8 T lymphocytes in the tumor microenvironment and to maintain HLA class I expression levels in combination with its direct cytotoxic effects.