According to the reports that HBx-induced resistance of hepatoma cells from complement attack in HCC and expression of C4BP was increased in HBx-transfected hepatic LO2 cells using cDNA microarray analysis [12, 13, 33], we are interested in whether HBx activates C4BP in the protection of hepatoma cells from complement attack in HCC. The gene discussed is C4BPA; the disease is hepatocellular carcinoma.