MHC class I chain related molecules A and B (MICA and MICB, danger signals), which are widely expressed in epithelial tumor cells, and virally or bacterially infected cells, can be recognized by γδ T cells and NK cells via NKG2D; a signaling pathway is responsible for enhanced cytotoxicity against infected cells or tumors [11], [12], [13]. The gene discussed is KLRK1; the disease is neoplasm.