title: Aberrant CpG island hypermethylation in dysplastic nodules and early HCC of hepatitis B virus-related human multistep hepatocarcinogenesis.
abstract: OBJECTIVE
  The concept of multistep hepatocarcinogenesis has been well-established, and an accumulation of methylating events has recently been demonstrated; however, the methylation status of low-grade dysplastic nodules (LGDN), high-grade dysplastic nodules (HGDN), and the recently introduced early hepatocellular carcinoma (eHCC) in hepatitis B virus (HBV)-related hepatocarcinogenesis has not yet been studied.
  
  
  METHODS
  One hundred thirty-three DNA samples (45 cirrhotic nodules, 29 LGDNs, 13 HGDNs, 14 eHCCs, and 32 progressed HCCs (pHCCs)) from HBV-infected resected livers were subjected to MethyLight analysis for nine CpG island loci (APC, RASSF1A, SOCS1, P16, COX2, SPRY2, PTEN, GNMT, and ERK), and COX2, RASSF1A, and SOCS1 protein expression status was analyzed by immunohistochemistry. The methylation status of each sample was correlated with the clinicopathological features.
  
  
  RESULTS
  APC, RASSF1A, and SOCS1 were methylated in 20 (44.4%), 25 (55.6%), and 13 (28.9%) of 45 cirrhosis samples, and APC (p=0.0008) and SOCS1 (p=0.0187) methylation were more frequent in dysplastic nodules and HCCs. APC (p=0.001) and RASSF1A (p=0.019) methylation levels were significantly increased from cirrhosis to LGDN. SOCS1 methylation gradually increased along multistep hepatocarcinogenesis, peaked at eHCC and decreased significantly in pHCCs (p=0.039). By contrast, p16 and COX2 was only methylated in dysplastic nodules and HCCs, with a stepwise increase up to pHCCs. As a whole, the frequency of methylation was highest in eHCCs. A stepwise decrease in COX2, RASSF1A, and SOCS1 protein expression was demonstrated.
  
  
  CONCLUSIONS
  A general stepwise increase in methylating events is seen during HBV-related multistep hepatocarcinogenesis, and epigenetic changes may occur predominantly in the earlier stages of HCC development.
authors.affiliation: Department of Pathology, Brain Korea 21 Project for Medical Science, Center for Chronic Metabolic Disease, Yonsei University Health System, Seoul, South Korea.
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Um
authors.forename: Haeryoung
authors.initials: H
authors.lastname: Kim
authors.forename: Bong-Kyeong
authors.initials: BK
authors.lastname: Oh
authors.forename: Myoung Soo
authors.initials: MS
authors.lastname: Kim
authors.forename: Kyung Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Guhung
authors.initials: G
authors.lastname: Jung
authors.forename: Young Nyun
authors.initials: YN
authors.lastname: Park
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics / Q000378:metabolism; D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000821:virology; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D018899:CpG Islands / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000150:complications / Q000235:genetics / Q000821:virology; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000821:virology; D008297:Male; D008875:Middle Aged; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D019941:Cyclin-Dependent Kinase Inhibitor p16; C411762:RASSF1 protein, human; C108944:SOCS1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D025521:Tumor Suppressor Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human