Stress-induced ligands, such as those recognized by the activating immunoreceptor natural killer group 2, member D (NKG2D) on NK cells (and on subpopulations of T cells) or danger signals, directly released from transformed cells (e.g. HMGB1), and damaged tissue may represent mechanisms of tumor cell recognition [97,98]. This evidence concerns the gene HMGB1 and neoplasm.