However, tumor cells have developed several mechanisms to circumvent NKG2D-mediated recognition, including the release of soluble ligands [118,119,120], the negative regulation of NKG2D ligand expression at the post-transcriptional level [121] and the secretion of immunosuppressive cytokines that reduce NK cell surface expression of NKG2D [122]. This evidence concerns the gene KLRK1 and neoplasm.