The immunological impact of neoadjuvant chemotherapy on the tumor microenvironment of esophageal squamous cell carcinoma

Abstract

Background: Esophageal cancer is an aggressive cancer with poor prognosis. However, little is known about the immune response in the tumor microenvironment after neoadjuvant chemotherapy.

Purpose: To investigate the immunological impact of neoadjuvant chemotherapy in the tumor microenvironment of esophageal squamous cell carcinoma.

Methods: 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.

Results: 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.

Conclusion: 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.