Li optimized the CAR specially for NK cell, utilizing NKG2D, a type 2 transmembrane-anchored C-type lectin-like protein; the 2B4 costimulatory domain and the CD3z signaling domain have a better result compared with the specifically target cancer cells in an antigen-specific manner to improve survival in an ovarian cancer xenograft model [54]. The gene discussed is KLRK1; the disease is cancer.