KLRK1 and hepatocellular carcinoma: NK cell intrinsic mechanisms. Recent investigations have demonstrated that, in HCC, NK cells upregulated the inhibitory receptors NKG2A, TIM3 and CD96 and downregulated TIGIT, NKG2D, NKp30, NKp46, sialic acid binding Ig-like lectin 7 (Siglec-7) and CD160 expression, which was associated with the impairment of NK cell function and poor prognosis [106,138,139,184,185].