KLRK1 and hepatocellular carcinoma: Another study confirmed that with anticancer drugs, HCC-derived exosomal HSP60, HSP70, and HSP90 were up-regulated, and these HSPs, including exosomes, efficiently enhanced NK cell cytotoxicity and granzyme B production by up-regulating inhibitory receptor CD94 and down-regulating activating receptors CD69, NKG2D, and NKp44 [44].