title: Immunohistochemical detection of c-Ha-ras oncogene p21 product in pre-neoplastic and neoplastic lesions during hepatocarcinogenesis in rats.
abstract: An immunohistochemical study of c-Ha-ras expression was performed on preneoplastic and neoplastic stages of diethylnitrosamine (DENA)-induced hepatocarcinogenesis in rats, using an antibody raised against a peptide sequence of the Ha-ras p21 product. Moderate to high immunostaining intensity was observed in the following hepatocytic lesions: (1) hepatocellular carcinomas (14/14) and associated neoplastic nodules (8/8) and foci of phenotypic alterations (35/40) (after 13-20 months of treatment); (2) neoplastic nodules (6/6) and associated foci (42/50) (after 5-9 months); (3) foci (10/10) (after 2 months); and (4) small, slowly growing foci (26/40) found 9 months after treatment with DENA without prior partial hepatectomy, resulting in low number of nodules and no tumor even after 15 months. No c-Ha-ras p21 was detected immunohistochemically in normal nor in regenerating rat liver. Our results indicate that increased Ha-ras expression is an early and stable event in liver lesions associated with hepatocarcinogenesis. They also imply that increased Ha-ras expression is insufficient (if at all implicated) for inducing fully malignant hepatocyte transformation. It might be indicative of cell populations at an increased transformation risk.
authors.affiliation: Laboratory of Cytology and Experimental Cancerology, School of Medicine, Free University of Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Galand
authors.forename: D
authors.initials: D
authors.lastname: Jacobovitz
authors.forename: K
authors.initials: K
authors.lastname: Alexandre
mesh_terms: D000818:Animals; D004261:DNA Replication; D004052:Diethylnitrosamine; D005260:Female; D011905:Genes, ras; D007150:Immunohistochemistry; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000473:pathology*; D008565:Membrane Proteins / Q000032:analysis*; D009857:Oncogenes; D011230:Precancerous Conditions / Q000235:genetics / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000276:immunology; D016283:Proto-Oncogene Proteins p21(ras); D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D004052:Diethylnitrosamine; D016283:Proto-Oncogene Proteins p21(ras)