PRF1 and hepatocellular carcinoma: The expression levels of perforin, granzyme-B and IFN-γ showed no significant difference in the combined treated group compared to control group and also TNF-α significantly down regulated in this group, indicating no synergic effect of NK cell and Sorafenib against HCC and the inhibitory effect of Sorafenib on the effector function of NK cells via cytokine production and degranulation.