To gain a better understanding of the pathology of liver disease, the signaling system controlling hepatocyte differentiation, proliferation, and apoptosis was selected as the theme of the 12th Yamaguchi Symposium on Liver Diseases. Ten leading researchers presented their latest experimental results. Focusing on apoptosis, guest speaker Professor D.A. Brenner, USA, spoke on the regulation of tumor necrosis factor alpha and Fas ligand-induced hepatic apoptosis by nerve factor-kappa B. Other researchers covered the molecular basis for clonal deletion therapy in hepatocellular carcinoma, hepatitis C virus induction of proliferation signals, helix-loop-helix protein in liver-specific gene expression, and reconstitution of hepatic tissues using liver stem cells, among other topics of current interest. These proceedings thus serve as a useful resource for all involved in hepatology research.