NCR2 and neoplasm: In addition to recognizing pathogen expressed ligands, the NCRs also recognize several other known ligands, including Heparan sulfates, which are recognized differentially by the different NCRs, (47) as well as BAT3 (expressed by stressed cells) and B7-H6 (expressed by tumor cells), which are recognized by NKp30, (48, 49) and MLL5, which has recently been identified as a tumor expressed protein ligand of NKp44 (16).