title: Rearrangement and enhanced expression of c-myc in hepatocellular carcinoma of hepatitis virus infected woodchucks.
abstract: Hepatocellularcarcinoma (HCC) that occur in woodchucks chronically infected with woodchuck hepatitis virus (WHV) were screened for activation of cellular oncogenes. Enhanced expression and allelic alterations of the c-myc oncogene were found in three HCC out of nine. Variations in the size of the c-myc transcripts, ranging from 2.0 kilobases (kb) to 5.6 kb, as well as in the level of c-myc gene expression, 5-50-fold higher than in adjacent liver tissues, were observed among the three HCC. Rearrangements of the c-myc locus were either upstream of the gene or within the first intron. Cloning and sequencing of the break-point region from one of the three tumours showed that the c-myc gene was truncated and joined to a unique cellular sequence of unknown function. WHV DNA was not integrated near the c-myc coding exons, excluding a direct role of the virus in c-myc activation. The novel type of rearrangement and activation of the c-myc gene, reported here in liver tumours of hepatitis virus infected animals, appears strikingly similar to those resulting from chromosomal translocations in human Burkitt's lymphomas, acute B- and T-cell leukaemias and mouse plasmacytomas.
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D005814:Genes, Viral; D006518:Hepatitis Viruses / Q000235:genetics*; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000382:microbiology*; D008392:Marmota; D009693:Nucleic Acid Hybridization; D009857:Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D004262:DNA Restriction Enzymes