Characterization of the occurrence and distribution of specific immune cells throughout the esophageal squamous cell carcinoma progression.

Esophageal squamous cell carcinoma (ESCC) is recognized as one of the most prevalent malignancies globally, with a notably high incidence in China. The disease often presents with subtle symptoms in its early stages, resulting in diagnoses at mid to late stages, which diminishes the possibility for radical surgical intervention. Additionally, the effectiveness, side effects, and resistance associated with radiotherapy and chemotherapy further constrain their use in treating ESCC. The advent of immune checkpoint inhibitors has expanded the array of immunotherapeutic strategies available for managing this condition. This study aims to delineate the occurrence and distribution of specific immune cell types throughout the progression of ESCC, utilizing a 4-NQO-induced murine model that most accurately reflects the initiation and progression of ESCC as observed in humans. This model encompasses various stages of ESCC development, including normal (NOR), inflammation (INF), hyperplasia (HYP), dysplasia (DYS), carcinoma in situ (CIS), and invasive cancer (ICA). Immunohistochemical analysis reveals an increase in the number of Ki67+ cells correlating with the advancement of ESCC, indicating elevated tumor cell proliferation. Notably, CD4+ and CD8+ T cells are prominently observed during the dysplastic stage, while CD20+ B cells and CD68+ macrophages are more prevalent during the hyperplastic stage. Furthermore, CD4+ and CD8+ T cells are actively involved in tumor recognition and elimination within the esophageal epithelium, whereas CD20+ B cells and CD68+ macrophages are primarily localized in the submucosal layer. This study underscores the role of immune cells in the pathogenesis of ESCC and suggests the timely application of immune checkpoint inhibitors may enhance anti-tumor immunity.