Are hematopoietic stem cells involved in hepatocarcinogenesis?

The liver has three cell lineages able to proliferate after a hepatic injury: the mature hepatocyte,the ductular “bipolar” progenitor cell termed “oval cell” and the putative periductular stem cell. Hepatocytescan only produce other hepatocytes whereas ductular progenitor cells are considerate bipolar since theycan give rise to biliary cells or hepatocytes. Periductular stem cells are rare in the liver, have a very longproliferation potential and may be multipotent, being this aspect still under investigation. They originatein the bone marrow since their progeny express genetic markers of donor hematopoietic cells afterbone marrow transplantation. Since the liver is the hematopoietic organ of the fetus, it is possible thathematopoietic stem cells may reside in the liver of the adult. This assumption is proved by the finding thatoval cells express hematopoietic markers like CD34, CD45, CD 109, Thy-1, c-kit, and others, which arealso expressed by bone marrow-derived hematopoietic stem cells (BMSCs). Few and discordant studieshave evaluated the role of BMSC in hepatocarcinogenesis so far and further studies in vitro and in vivo arewarranted in order to definitively clarify such an issue.