KLRK1 and neoplasm: In contrast to the high specificity and memory of CAR T cells, CIK cells are capable of eliminating tumor cells by recognizing pathogen patterns through a variety of receptors (DNAM-1, NKG2D, NKp30, and TCR/CD3) (24), suggesting that ERBB2-CAR CIK cells may provide NK cell-like activities, mainly NKG2D-mediated functions, and specific anti-ERBB2-mediated cytotoxicity in combination, as indicated by NK and T-NK cells which were present at potential tumor sites in all ERBB2-CAR CIK cell-treated mice.