KLRK1 and neoplasm: This result is consistent with our previous study with Vγ9Vδ2 T cells modified with different NKG2D CARs, in which the 1st generation of NKG2D RNA CAR displayed a superior tumor cell cytolytic activity as compared to the 2nd and 3rd generation RNA CARs in a short-term cytotoxicity assay, possibly because mRNA encoding the 1st generation CAR is smaller in size [25].