The liver in subacute hepatic failure may become enriched for hepatic progenitor cells. Liver tissue from such a patient was collagenase digested and, from the nonparenchymal cell fraction, epithelioid colonies were developed. Albumin and alpha-1-antitrypsin (AAT) were secreted for greater than 120 days from these colonies. Reverse transcription-polymerase chain reaction showed expression of markers of both hepatocyte and biliary epithelial phenotypes (cytokeratins 7, 18, and 19, albumin and AAT, hepatocyte growth factor receptor, transforming growth factor beta receptor type II, gamma-glutamyl transpeptidase, biliary glycoprotein). The cell cycle regulator p21 was also expressed. The POU domain transcription factor octamer-binding protein 4 was present in these cells, but not in RNA or cDNA prepared from adult human liver. These markers were maintained even after 165 days culture. Proliferating epithelial-like cells with combined hepatocyte- and biliary-epithelial-specific functional markers and a stem cell marker can be isolated from the nonparenchymal fraction of liver cells in subacute hepatic failure.