INTERMEDIATE FILAMENT REACTIVITY IN HYPERPLASTIC AND NEOPLASTIC LESIONS FROM MEDAKA (ORYZIAS-LATIPES)

To determine if hyperplastic and neoplastic lesions from medaka showed similar immunoreactivity to intermediate filament antibodies as the t issues of origin, two week old medaka were exposed to 10 or 20 mg/L of methylazoxymethanol acetate for two hours and transferred to clean wa ter for up to six months. Using a streptavidin peroxidase method, para ffin embedded Bouins fixed neoplasms were incubated with cytokeratin, vimentin, or neurofilament antibodies. Like their nonneoplastic cellul ar counterparts, hepatocellular carcinoma, pancreatic acinar carcinoma and mesenchymal neoplasms including hemangioma and hemangiopericytoma reacted negatively to cytokeratin antibodies. Cholangiocarcinoma, mes othelioma, and proliferative lesions containing biliary epithelial cel ls reacted positively to cytokeratin antibodies. All neoplasms and pro liferative lesions were negative with vimentin and neurofilament antib odies. These data indicate that while some epithelial neoplasms showed cytokeratin reactivity similar to the parent tissues, additional mark ers are needed to identify mesenchymal tissues and neoplasms.