Solid evidence has demonstrated that NK group 2D (NKG2D) ligands, such as MICA/MICB in human HCC cells and RAE-1 in murine HCC cells, represent one of the determinant factors of NK cell cytotoxicity through interaction with the NKG2D receptor on NK cells [9, 10]. The gene discussed is MICB; the disease is hepatocellular carcinoma.