CD244 and neoplasm: NKp44 (encoded by NCR2) is another activating receptor capable of binding to HLA-DP (MHC-II) on viral peptide presentation, although a tumor ligand has not yet been identified, and the 2B4-CD48 interaction, expressed on NK and tumor cells, respectively, also induces NK cell activation by increasing cytotoxicity and IFNγ secretion [8,34].