Comparative analysis of tumor-infiltrating lymphocytes in a syngeneic mouse model of oral cancer.

OBJECTIVE: To perform a comparative analysis of infiltrating immune cells in a newly developed C57BL/6 background syngeneic transplantable mouse oral cancer (MOC) model. STUDY DESIGN/
SETTING: Scientific study in an academic medical center.
METHODS: Use of carcinogen-induced tumorigenesis, tissue culture, cell line transplantation, and flow cytometric analysis techniques.
RESULTS: Previously, the authors established a series of cell line models that displayed dichotomous growth phenotypes when transplanted into immunocompetent mice. They now show that the indolent growth pattern of the MOC1-generated tumors is associated with increased baseline and inducible major histocompatibility complex class I expression and increased CD8(+) T-cell infiltration into the tumor microenvironment. Conversely, the aggressive and metastatic pattern of MOC2-generated tumors has decreased basal and inducible class I expression and is associated with FOXP3(+)CD4(+) regulatory T-cell infiltration. Delayed primary tumor growth after targeted monoclonal antibody therapy of these FOXP3(+) regulatory cells further suggests that these immune cells contribute to the aggressive phenotype of MOC2.
CONCLUSION: These data validate that key infiltrating immune cells identified here parallel findings in human head and neck cancer, making this newly developed syngeneic model a critical platform for the continued dissection of tumor-host interactions in head and neck cancer.