During the last years much attention has been given to the investigation of the roles of specific growth modulators acting on liver cell populations. HGF functions as a pleotropic factor in the liver as well as in other extrahepatic tissues. The hepatic stem cell compartment is thought to play a major role in liver tissue restoration. Mechanisms of cell growth and cell death of the liver are described in detail, with particular emphasis on apoptosis. The functions of HBV-pX protein and the roles of hepatitis B virus gene expression relation to hepatocellular carcinoma are discussed. Techniques for obtaining human and nonhuman hepatocytes and other liver cell