The liver can regenerate, but this ability is lost in chronic liver disease. Because donor organs for liver transplantation are sparse, our goal is to establish novel means of liver regeneration. For example, we are working to develop liver cell therapy with hepatocytes derived from pluripotent stem cells. For this, we are using signals that regulate the proliferation and differentiation of primary liver stem/progenitor cells to convert pluripotent stem cells into therapeutically effective and expandable hepatocytes. In addition to losing its regenerative capacity, the diseased liver undergoes scarring and develops cancer. Another goal of our laboratory is to understand the mechanisms that lead to liver cancer formation, in particular with regard to the role of liver stem/progenitor cells.