Immunohistochemical analysis of metastasising hepatocellular carcinomas in dogs

In this study, the immunohistochemical features of primary hepatocellular carcinomas and their metastases in visceral organs, including the lungs, spleen and kidneys were examined using antibodies against carcino-embryonic antigen (CEA) cytokeratin (CK) 7 and 20, CD4, CD8, minichromosome maintenance protein 3 (MCM3), vimentin, and alpha 1 foetoprotein (AFP). In addition, Mallory's connective tissue stain, van Gieson's stain and Gomori methenamine silver stain were used. The study was performed on liver samples collected post mortem from five mixed-breed dogs aged 9-12 years. The tumours were classified according to the World Health Organization Classification of Tumours. Strong expression of MCM3 and AFP was found in the hepatic cancer cells and in the metastases to the lungs, spleen and kidneys. The primary tumours and metastatic foci did not react positively with the anti-CD4, anti-CD8, CEA, CK7 and CK20 antibodies. The connective tissue in the primary tumour and the metastases showed a positive reaction to vimentin. Canine hepatocellular carcinomas that metastasise are highly-malignant well-differentiated tumours that produce AFP and trace amounts of both carcinoembryonic antigen and cytokeratin. Therefore, the metastasis resembles the primary tumour and has a common phenotype and genotype with the primary tumour.