It has been reported that levels of soluble
intercellular adhesion molecule-1 (ICAM-1) in the blood are elevated in
hepatocellular carcinoma patients. In the present study, serial observations of the localization of
ICAM-1 in the liver were made by light and electron microscopy in rats with
carcinogen-induced
cancer. Male Fisher rats were given
diethylnitrosamine (DEN) orally in their
drinking water. Rats were sacrificed at 6, 8, 12, or 14 weeks after the start of DEN administration and the liver tissue was collected.
ICAM-1 expression in liver was assessed using indirect immunoperoxidase staining with anti-rat
ICAM-1 antibody. Although
ICAM-1 expression by endothelial cells in livers of DEN-treated rats was lower than in the control group at 8 weeks, it was higher in the membrane and cytoplasm of hepatocytes. The expression of
ICAM-1 in mesenchymal cells was decreased, paralleling development of cellular atypia, whereas in hepatocyte membranes and cytoplasm it was increased in these atypia.
ICAM-1 was localized to the cytoplasm of
cancer cells, but to the membrane of hepatocytes in the treated livers at 14 weeks. Furthermore, the levels of
ICAM-1 in mesenchymal cells tended to be lower in the cancerous area than in the atypical hyperplastic nodule, and were reduced as the density of cell atypia increased, in comparison to cells in areas without cancerous nodules. We concluded that
ICAM-1 may be influenced the development of
cancer induced in the rat liver by a chemical
carcinogen.