title: Clonal expansion of hepatocytes with a selective advantage occurs during all stages of chronic hepatitis B virus infection.
abstract: Hepatocyte clone size was measured in liver samples of 21 patients in various stages of chronic hepatitis B virus (HBV) infection and from 21 to 76 years of age. Hepatocyte clones containing unique virus-cell DNA junctions formed by the integration of HBV DNA were detected using inverse nested PCR. The maximum hepatocyte clone size tended to increase with age, although there was considerable patient-to-patient variation in each age group. There was an upward trend in maximum clone size with increasing fibrosis, inflammatory activity and with seroconversion from HBV e-antigen (HBeAg)-positive to HBeAg-negative, but these differences did not reach statistical significance. Maximum hepatocyte clone size did not differ between patients with and without a coexisting hepatocellular carcinoma. Thus, large hepatocyte clones containing integrated HBV DNA were detected during all stages of chronic HBV infection. Using laser microdissection, no significant difference in clone size was observed between foci of HBV surface antigen (HBsAg)-positive and HBsAg-negative hepatocytes, suggesting that expression of HBsAg is not a significant factor in clonal expansion. Laser microdissection also revealed that hepatocytes with normal-appearing histology make up a major fraction of the cells undergoing clonal expansion. Thus, preneoplasia does not appear to be a factor in the clonal expansion detected in our assays. Computer simulations suggest that the large hepatocyte clones are not produced by random hepatocyte turnover but have an as-yet-unknown selective advantage that drives increased clonal expansion in the HBV-infected liver.
authors.affiliation: Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.|Centenary Institute, Sydney, NSW, Australia.|Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Tu
authors.affiliation: Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Mason
authors.affiliation: Centre for Liver Disease Research, School of Medicine, Faculty of Health Sciences, University of Queensland, Brisbane, QLD, Australia.
authors.forename: A D
authors.initials: AD
authors.lastname: Clouston
authors.affiliation: Centenary Institute, Sydney, NSW, Australia.|Sydney Medical School, University of Sydney, Sydney, NSW, Australia.|A. W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: N A
authors.initials: NA
authors.lastname: Shackel
authors.affiliation: Centenary Institute, Sydney, NSW, Australia.|Sydney Medical School, University of Sydney, Sydney, NSW, Australia.|A. W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
authors.forename: G W
authors.initials: GW
authors.lastname: McCaughan
authors.affiliation: Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Yeh
authors.affiliation: Schiff Liver Institute and Center for Liver Diseases, Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Schiff
authors.affiliation: Department of Anatomical Pathology and Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia.
authors.forename: A R
authors.initials: AR
authors.lastname: Ruszkiewicz
authors.affiliation: South Australian Liver Transplant Unit, Flinders Medical Centre, Adelaide, SA, Australia.
authors.forename: J W
authors.initials: JW
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA, Australia.
authors.forename: H A J
authors.initials: HA
authors.lastname: Harley
authors.affiliation: Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: U H
authors.initials: UH
authors.lastname: Stroeher
authors.affiliation: Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: A R
authors.initials: AR
authors.lastname: Jilbert
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology; D049109:Cell Proliferation; D060965:Clonal Evolution; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D006515:Hepatitis B virus / Q000235:genetics / Q000502:physiology*; D019694:Hepatitis B, Chronic / Q000473:pathology*; D022781:Hepatocytes / Q000502:physiology*; D006801:Humans; D061346:Laser Capture Microdissection; D008099:Liver / Q000473:pathology*; D008103:Liver Cirrhosis / Q000473:pathology; D008113:Liver Neoplasms / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D013997:Time Factors; D016662:Virus Integration; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens
keywords: clonal expansion of hepatocytes; hepatitis B virus; hepatocellular carcinoma; inverse nested PCR; laser microdissection; virus-cell DNA junction