Tumour cells use various strategies for this immune suppression or escape: for example, multiple types of tumour cells suppress the expression of NK group D2 (NKG2D) ligands, such as UL16 binding protein (ULBP) 1/2/3 and MHC class I polypeptide-related sequence (MIC) A/B, which reduces their recognition by endogenous NK cells12. This evidence concerns the gene KLRK1 and neoplasm.