HLA-C and cancer: The IS involves interactions between immune killer cells (NK cells and CTLs) with their APCs or targeted cancer cells necessary to achieve maturation and production of TNF-α and IFN-γ, and their lytic functions (267–269) IS formation in T cells is regulated by cytoskeletal elements (i.e. actin), interaction of MHC-TCR, and the integration of integrin-based signals, generated when integral molecules (lymphocyte function-associated antigen 1, LFA-1) on the T cell interact with ICAM-1.