Impact of tumor-infiltrating LAMP-3 dendritic cells on the prognosis of esophageal squamous cell carcinoma

Background Dendritic cells (DCs) are the most potent antigen-presenting cells to induce cytotoxic T lymphocytes in the tumor environment. After acquiring antigens, DCs undergo maturation and their expression of MHC and co-stimulation molecules are enhanced, along with lysosome-associated membrane glycoprotein 3 (LAMP-3), which is a specific marker of mature DCs. In general, mature DCs are usually considered to be immunostimulatory in the cancer microenvironment. In addition, it is known that tumor-infiltrating lymphocytes (TILs) are associated with a good prognosis in esophageal squamous cell carcinoma (ESCC). However, few studies have targeted the interaction between DCs and TILs in the local immunity of ESCC. We investigated the localization of mature DCs within ESCC tissue and their relationship to TILs as well as the clinical outcome. Methods We evaluated 80 ESCC patients who underwent surgical treatment without preoperative treatment, using immunohistochemistry with LAMP-3 and CD8. Results The results showed that LAMP-3 DCs were predominantly observed in the peritumoral area. Intratumoral CD8 T cells were found to be associated with a favorable prognosis, and the number of infiltrating LAMP-3 DCs was correlated with the number of intratumoral CD8 T cells. Conclusion At the local tumor site, mature LAMP-3 DCs might be associated with increasing tumor infiltrating CD8 T cells.