Activating receptors of NK cells, such as NKG2D, CD226, and NKp30, are downregulated on NK cells and correlate inversely with the progression and metastasis of melanoma, colorectal carcinoma, hepatocellular carcinoma (HCC), breast cancer, prostate cancer, gastric cancer, and others (18). This evidence concerns the gene NCR3 and hepatocellular carcinoma.