Demonstration by light and ultrastructural immunoperoxidase study of α-fetoprotein-positive non-hepatoma cells and hepatoma cells during 3−methyl-4-dimethylaminoazobenzene hepatocarcinogenesis

Abstract

Immunoreaction of alpha-fetoprotein (AFP) has been described in cholangiolar "oval" cells in the early stage of 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis. The subcellular location of AFP in the oval cells was in the perinuclear space, rough endoplasmic reticulum and Golgi apparatus. In livers with hyperplastic nodules there were two different types of foci containing AFP-positive cells. One type had a normal nucleocytoplasmic ratio and was seen in well-preserved hepatic trabecular structures, and the other had less cytoplasm and occurred in trabecular structures in disarray. AFP-immunoreactivity in the former type was visible in the perinuclear space and rough endoplasmic reticulum but scarce in the Golgi apparatus, and in the latter type it was present in the proliferative smooth endoplasmic reticulum and in several parts of Golgi apparatus in the submembranous or pericanalicular areas. In livers with hepatocarcinoma, AFP immunoreaction was detected in well-differentiated hepatocellular carcinomas, and the subcellular location of AFP was in the perinuclear space, rough endoplasmic reticulum and many developed Golgi complexes. Therefore, AFP-positive cells in livers with hyperplastic nodules are a new cell population in hepatocarcinogenesis, and each type is morphologically different from the oval cell.