Although reposition of functional NK cells in hepatic tissues of HCC patients could improve survival rate of them [58], often reduced infiltration and impaired functional activities, including TNF-α and IFN-γ production as well as releasing cytoplasmic granules (i.e., granzyme A, granzyme B and perforin), could be observed in advanced HCC patients and might be associated with the progression and invasion of HCC [54]. This evidence concerns the gene PRF1 and hepatocellular carcinoma.