Squamous cell tumors recruit ?? T cells producing either IL17 or IFN? depending on the tumor stage

The identification of reciprocal interactions between tumorinfiltrating immune cells and the microenviromentmay help us understand mechanisms of tumor growth inhibition or progression. We have assessed the frequencies of tumor-infiltrating and circulating ?? T cells and regulatory T cells (Treg) from 47 patients with squamous cell carcinoma (SCC), to determine if they correlated with progression or survival. V?1 T cells infiltrated SSC tissue to a greater extent than normal skin, but SCC patients and healthy subjects had similar amounts circulating. However, V?2 T cells were present at higher frequencies in circulation than in the tissue of either cancer patients or healthy donors. Tregs were decreased in the peripheral blood of SCC patients, but were significantly increased in the tumor compartment of these patients. Tumor-infiltrating ?? T cells preferentially showed an effector memory phenotype and made either IL17 or IFN? depending on the tumor stage, whereas circulating ?? T cells of SCC patients preferentially made IFN?. Different cell types in the tumor microenvironment produced chemokines that could recruit circulating ?? T cells to the tumor site and other cytokines that could reprogram ?? T cells to produce IL17. These findings suggest the possibility that ?? T cells in SCC are recruited from the periphery and their features are then affected by the tumor microenvironment. Elevated frequencies of infiltrating V?2 T cells and Tregs differently correlated with early and advanced tumor stages, respectively. Our results provide insights into the functions of tumor-infiltrating ?? T cells and define potential tools for tumor immunotherapy.