The identity of ligands for NCRs is a field of intense investigations; nuclear leukocyte antigen-B-associated transcript 3 (BAT3) factor, which is released from tumor cells under stress conditions, and a member of the B7 family, B7-H6, only expressed on tumor cells, both have been identified as cellular ligands for NKp30 (7, 8). This evidence concerns the gene NCR3LG1 and neoplasm.