The malignant proliferation, invasion, and metastasis of HCC cells have been associated with the NK cell immune function of the patients [10], such as the cytotoxicity of primary NK cells from the hepatoma patients against SMMC7721 or HepG2 cells displayed a significant reduction, and also were positively associated with the level of miR-506 and negatively correlated with the mRNA level of STAT3 [11]. Here, STAT3 is linked to hepatocellular carcinoma.