title: Quantification of hepatitis B virus covalently closed circular DNA in patients with hepatocellular carcinoma.
abstract: OBJECTIVE
  This study aimed to measure the intrahepatic total hepatitis B virus (HBV) DNA and covalently closed circular DNA (cccDNA) levels in tumor and non-tumor tissues in hepatocellular carcinoma (HCC) patients.
  
  
  METHODS
  Intrahepatic total HBV DNA and cccDNA were measured in 25 HCC patients (21 hepatitis B surface antigen [HBsAg]-positive and 4 HBsAg-negative) by the Invader assay.
  
  
  RESULTS
  A low level of intrahepatic HBV DNA was detectable in all HBsAg-negative patients. For HBsAg-positive patients, the intrahepatic total HBV DNA levels in the tumor and non-tumor tissues were comparable (P=0.903). However, the tumor tissues had significantly higher levels of cccDNA (0.35 vs. 0.16 copies/cell, P=0.030) and higher proportion of intrahepatic HBV DNA in the form of cccDNA (100% vs. 84%, P=0.004) than the non-tumor tissues. Seventeen out of 21 (81%) tumor tissues had intrahepatic HBV DNA solely in cccDNA form. Analysis of HBV mRNA expression indicated that HBV replication appeared to be lower in the tumor tissues than the non-tumor tissues.
  
  
  CONCLUSIONS
  Compared to the non-tumor tissues, the levels of HBV replication in the tumor tissues appeared to be lower, and cccDNA was the predominant form of HBV DNA in the tumor tissues.
authors.affiliation: Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China.
authors.forename: Danny Ka-Ho
authors.initials: DK
authors.lastname: Wong
authors.forename: Man-Fung
authors.initials: MF
authors.lastname: Yuen
authors.forename: Ronnie Tung-Ping
authors.initials: RT
authors.lastname: Poon
authors.forename: John Chi-Hang
authors.initials: JC
authors.lastname: Yuen
authors.forename: James
authors.initials: J
authors.lastname: Fung
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Lai
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000821:virology*; D004270:DNA, Circular / Q000032:analysis / Q000302:isolation & purification*; D004279:DNA, Viral / Q000032:analysis / Q000302:isolation & purification; D005260:Female; D015967:Gene Expression Regulation, Viral; D006514:Hepatitis B Surface Antigens / Q000378:metabolism; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000150:complications / Q000821:virology*; D006801:Humans; D008099:Liver / Q000821:virology; D008113:Liver Neoplasms / Q000821:virology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis / Q000302:isolation & purification; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004270:DNA, Circular; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D012333:RNA, Messenger; D012367:RNA, Viral