TY - JOUR
T1 - Genetic instability and aberrant DNA methylation in chronic hepatitis and cirrhosis - A comprehensive study of loss of heterozygosity and microsatellite instability at 39 loci and DNA hypermethylation on 8 CpG islands in microdissected specimens from patients with hepatocellular carcinoma
AU - Kondo, Yutaka
AU - Kanai, Yae
AU - Sakamoto, Michiie
AU - Mizokami, Masashi
AU - Ueda, Ryuzo
AU - Hirohashi, Setsuo
N1 - Funding Information:
Abbreviations: HCC, hepatocellular carcinoma; hMLH1, human Mut L homologue 1; THBS-1, thrombospondin-1; MINT, methylated in tumor; LOH, loss of heterozygosity; MSI, microsatellite instability; HBV, hepatitis B virus; HCV, hepatitis C virus; PCR, polymerase chain reaction; MSP, methylation-specific polymerase chain reaction. From the 1Pathology Division, National Cancer Center Research Institute, Tokyo, Japan; and the 2Second Department of Medicine, Nagoya City University Medical School, Nagoya, Japan. Received June 20, 2000; accepted September 12, 2000. Supported by a Grant-in-Aid for the 2nd Term Comprehensive 10-Year Strategy for Cancer Control and by a Grant-in-Aid for Cancer Research from the Ministry of Health and Welfare, Japan. Yutaka Kondo is a recipient of a Research Resident Fellowship from the Foundation for Promotion of Cancer Research in Japan. Address reprint requests to: Setsuo Hirohashi, M.D., Pathology Division, National Cancer Center Research Institute, 5-1-1, Tsukiji, Chuo-ku, Tokyo 104-0045, Japan. E-mail: shirohas@ncc.go.jp; fax: (81) 3-3248-2463. Copyright © 2000 by the American Association for the Study of Liver Diseases. 0270-9139/00/3205-0014$3.00/0 doi:10.1053/jhep.2000.19797
PY - 2000
Y1 - 2000
N2 - A study was conducted to examine the significance of genetic instability and aberrant DNA methylation during hepatocarcinogenesis. Genomic DNA was extracted from 196 microdissected specimens of noncancerous liver tissue that showed no marked histologic findings or findings compatible with chronic hepatitis or cirrhosis, and 80 corresponding microdissected specimens of hepatocellular carcinoma (HCC) from 40 patients. Loss of heterozygosity (LOH) and microsatellite instability (MSI) were examined by polymerase chain reaction (PCR) using 39 microsatellite markers, and DNA methylation status on 8 CpG islands was examined by bisulfite-PCR. In noncancerous liver tissues, LOH, MSI, and DNA hypermethylation were found in 15 (38%), 6 (15%), and 33 (83%) of 40 cases, respectively. The incidence of DNA hypermethylation in histologically normal liver was similar to that in chronic hepatitis and cirrhosis, although neither LOH nor MSI was found in histologically normal liver. In cancerous tissues, LOH, MSI, and DNA hypermethylation were found in 39 (98%), 8 (20%), and 40 (100%) of 40 cases, respectively. CpG islands of the p16 gene and methylated in tumor 1, 2, 12, and 31 clones were frequently methylated in cancerous tissues, although neither the thrombospondin-1 nor the human Mut L homologue (hMLH1) gene was methylated. Absence of silencing of the hMLH1 gene by DNA hypermethylation is consistent with the low incidence of MSI in HCCs. The results of this study indicate that LOH and aberrant DNA methylation contribute to hepatocarcinogenesis; DNA hypermethylation in particular, which precedes or may even cause LOH, is as an early event during hepatocarcinogenesis.
AB - A study was conducted to examine the significance of genetic instability and aberrant DNA methylation during hepatocarcinogenesis. Genomic DNA was extracted from 196 microdissected specimens of noncancerous liver tissue that showed no marked histologic findings or findings compatible with chronic hepatitis or cirrhosis, and 80 corresponding microdissected specimens of hepatocellular carcinoma (HCC) from 40 patients. Loss of heterozygosity (LOH) and microsatellite instability (MSI) were examined by polymerase chain reaction (PCR) using 39 microsatellite markers, and DNA methylation status on 8 CpG islands was examined by bisulfite-PCR. In noncancerous liver tissues, LOH, MSI, and DNA hypermethylation were found in 15 (38%), 6 (15%), and 33 (83%) of 40 cases, respectively. The incidence of DNA hypermethylation in histologically normal liver was similar to that in chronic hepatitis and cirrhosis, although neither LOH nor MSI was found in histologically normal liver. In cancerous tissues, LOH, MSI, and DNA hypermethylation were found in 39 (98%), 8 (20%), and 40 (100%) of 40 cases, respectively. CpG islands of the p16 gene and methylated in tumor 1, 2, 12, and 31 clones were frequently methylated in cancerous tissues, although neither the thrombospondin-1 nor the human Mut L homologue (hMLH1) gene was methylated. Absence of silencing of the hMLH1 gene by DNA hypermethylation is consistent with the low incidence of MSI in HCCs. The results of this study indicate that LOH and aberrant DNA methylation contribute to hepatocarcinogenesis; DNA hypermethylation in particular, which precedes or may even cause LOH, is as an early event during hepatocarcinogenesis.
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U2 - 10.1053/jhep.2000.19797
DO - 10.1053/jhep.2000.19797
M3 - Article
C2 - 11050047
AN - SCOPUS:0033765496
SN - 0270-9139
VL - 32
SP - 970
EP - 979
JO - Hepatology
JF - Hepatology
IS - 5
ER -