TIGIT and head and neck squamous cell carcinoma: TIGIT can interfere with the cancer immunity cycle in a variety of ways, including suppression of NK12 and  CD8+ T cell-mediated killing,11 induction of immunosuppressive dendritic cells (DCs),10 and skewing CD4+ and CD8+ T cell priming and differentiation to immunosuppressive phenotypes.15,16 Data pooled from the TCGA database reveals several human cancers that have increased expression of TIGIT including colon, cervical, ovarian, head and neck squamous cell carcinoma (HNSCC), acute myeloid leukemia, multiple myeloma, and non-small cell lung cancer (NSCLC).