Cytokeratin 8/18 is a Useful Immunohistochemical Marker for Hepatocellular Proliferative Lesions in Mice

In order to clarify whether cytokeratin (CK) 8/18 is a useful immunohistochemical market rot hepatocellular proliferative lesions in mice. partially hepatectomized male ICR mice were given 0.6% piperonyl butoxide (PBO) for 8 (Experiment I) or 25 weeks (Experiment II) alter N-diethylnitrosamine (DEN) initiation treatment, and the livers were subjected to histological examinations on hematoxylin and eosin (HE) stained sections. CK 8/18 immunohistochemistry and gamma-glutamyl transpeptidase (GGT) histochemistry In Experiment I. the multiplicity of hepatocellular foci in paraffin-embedded sections which were observed in HE-stained sections and positive rot CK8/18 was 10 17 and IS 50, respectively. while that or hepatocellular foci in frozen sections which were observed in HE-stained sections and positive/negative for GGT Was 6 17 and 8 17, respectively In Experiment II, the total multiplicity of hepatocellular foci in paraffin-embedded sections which were observed in HE-stained sections and positive/negative in CK8/18 was 4 47 and 23 17. respectively, while that of hepatocellular foci in frozen sections which were observed in HE-stained sections and positive/negative for GGT was 2 50 and 3 50. respectively Most of the hepatocellular adenomas and carcinomas observed in HE-stained sections were positive for CK8/18. but Sortie of the adenomas were negative for CK8/18 These findings indicate that more hepatocellular poliferative lesions can he detected in CK8/18 immunohistochemistry in addition to those observed in HE-stained sections. and suggest that CK8/18 may become a useful immunohistochemical marker lot detecting hepatocellular proliferative lesions in mice