Comparative immunohistochemical investigation of rat and human hepatocellular carcinomas

Abstract

Previously identified comparable morphological features of human and rat hepatoproliferative lesions were identified, including hepatocellular carcinomas (HCCs). In this study we identified similarities and differences in immunohistochemical (IHC) detection of some key proteins important in carcinogenesis that may link pathogenesis pathways of human and rat HCC. The comparative features of six IHC markers (Ki-67, beta-catenin, CD34, glutamine synthetase (GS), c-myc, and transforming growth factor alpha (TGF-alpha)), previously shown to be positive or altered in rodent and human HCC when compared to normal hepatocytes, were investigated. Glutamine synthetase (a hepatocellular enzyme) was strongly positive in 5/5 (100%) human and 4/5 (80%) rat HCCs examined. CD34 (an endothelial marker) and Ki-67 (a cell proliferation marker) were consistently positive in five human HCCs (5/5 for both markers) but weakly positive in only 2/5 and 3/5 rat HCCs, respectively. Beta-catenin, c-myc, and TGF-alpha were infrequently altered, with immunopositivity found in only one or two of either rat or human HCCs (a total of five each examined; beta-catenin: 1/5 rat samples, c-myc: 2/5 human samples, TGF-alpha: 1/5 rat samples positive). It was concluded that Ki-67, CD34, and GS, are most likely to be useful in studying the pathogenesis of HCC in rats and humans.