Since the frequency of activating KIR–HLA pairs did not differ significantly between the HCC and non-HCC groups, the inhibitory KIR3DL1+HLA-Bw4 pair, which showed a high and significantly greater frequency in the HCC group, might have contributed to HCC onset by escaping immune surveillance and other intrahepatic inflammatory processes. The gene discussed is KIR3DL1; the disease is hepatocellular carcinoma.