Viral hepatitis and hepatocellular carcinoma prevention strategy in Japan

The study of human hepatitis, particularly in Asia, where the incidence rate has been the highest in the world, has contributed greatly to the understanding of carcinogenesis of the liver and related diseases. In this article, the history of research on hepatitis viruses and hepatocellular carcinoma (HCC) and the successful prevention of vertical transmission of hepatitis B virus (HBV) in Japan are reviewed, focusing on the studies that resulted in the identification of vertical transmission of HBV infection and the association of HBV-sustained infection and HCC. The vaccination trials for preventing HBV vertical transmission and the fruitful outcome of the nationwide vaccination strategy in Japan, on the basis of "selective" immunization by using anti-HBs immunoglobulin (HBIG) and HB vaccine, are highlighted. Ongoing studies on the mechanisms underlying hepatocarcinogenesis induced by viruses, e.g., the roles of viral proteins and inflammation, are also reviewed, and prospects for the control of HCC are discussed.