KLRK1 and cancer: Consistent with previous studies [33], several activating receptors on NK cells, including CD69, NKG2D, NKp44, and 4-1BB, and functional molecules, such as IFN-γ, Granzyme B, CD107a, and TRAIL, were increased after treatment, which expression were decreased in cancer patients as a sign of NK cell exhaustion [34, 35].