A local enrichment of regulatory T cells within the tumor tissue might suppress an effective anti-tumor T cell response in patients with head and neck cancer

9666 Background: Head and neck cancer has traditionally been regarded as a tumor type exerting a suppressive effect on the T cell-mediated immune system. Here, we examined the expression of a variety of tumor-associated antigens as possible targets for a T cell response in tumors of patients with head-and-neck cancer. Next, we analyzed whether a local accumulation of regulatory T cells within the tumor might contribute to a suppression of an effective immune response. Methods: We analyzed the expression of cancer testis (CT) antigens NY-ESO-1, MAGE-A3, MAGE-C1, MAGE-E1, SSX-1, SSX-2, ADAM2 (CT15), LIP1 (CT17), and HOM-TES-85 in tumor samples and adjacent healthy tissue of patients with head and neck cancer (N=35) using rt-PCR. Furthermore, we analyzed the expression of Foxp3, a marker gene for regulatory T cells (Treg), in tissue samples of the same patients using real-time PCR. For comparison, quantitative PCR for Foxp3 expression was also applied to non-malignant tissue derived from inflamed tonsils of ...