Hepatic progenitor cells in hepatocellular adenomas

Hepatocellular adenoma is a benign tumor of the liver that has a small but not negligible risk of malignant transformation into hepatocellular carcino ma. In analogy with the established role of oval cells in hepatocarcinogene sis in rodent models, human hepatic progenitor cells may have a function in the development of liver tumors. To investigate this issue, we performed i mmunohistochemistry on biopsies of 10 consecutively resected hepatocellular adenomas using mark ers for hepatic progenitor cells. Sections of paraffin -embedded and frozen biopsies were stained using antibodies against cytoker atins 7, 8, 18, and 19, chromogranin-A, OV-6, and neural cell adhesion mole cule. Hepatic progenitor cells were observed in five of 10 hepatocellular a denomas. These five tumors also contained cells with an immunohistochemical phenotype intermediate be tween hepatic progenitor cells and hepatocytes. Hepatic progenitor cells and intermediate hepatocyte-like cells were scatte red throughout the tumors with a density that varied from area to area. Ult rastructural examination confirmed the presence of hepatic progenitor cells . Our study shows that hepatic progenitor cells are present in a considerab le proportion of hepatocellular adenomas, supporting the hypothesis that hu man hepatic progenitor cells can play a role in the development of heptocel lular tumors.