Bcl-2 protein expression in acute and chronic hepatitis, cirrhosis and hepatocellular carcinoma

Bcl-2 protein blocks apoptosis and is involved in human intrahepatic bile-d uct development. Formalin-fixed, paraffin-embedded archival tissue from 42 HBV and HCV hepatitis [20 acute AH, 22 chronic hepatitis (CH)], 12 active c irrhosis (CR) and 20 hepatocellular carcinoma (HCC) was immunostained for b cl-2 protein. In all cases, bcl-2 protein was detected in portal and intralobular lymphoc ytes but not in hepatocytes or Kupffer cells. Bcl-2 was positive in the cyt oplasm of small portal bile ducts of chronic hepatitis, while it was strong ly expressed in newly formed bile-ductules of the limiting plate, mainly in CH with marked activity and CR. Bcl-2 was detected in small bile ducts in only one case of acute hepatitis and was not detected in any case of HCC. Bcl-2 seems to be involved in the regulation of growth and apoptosis of cho langiolar cells. Its expression in small bile ducts and in newly-formed duc tules especially in CH with marked activity and CR, implies that the embryo nic model of intrahepatic bile duct development may be recapitulated in chr onic hepatic disease. Moreover, it supports evidence for the existence of t he controversial long-lived stem population in the liver. Bcl-2 does not se em to be involved in hepatocarcinogenesis.