Genome-wide analysis of DNA methylation identifies novel cancer-related genes in hepatocellular carcinoma

First Department of Internal Medicine, Sapporo Medical University, S1, W16, Chuo-Ku, Sapporo, 060-8543, Japan.
Tumor Biology (Impact Factor: 3.61). 03/2012; 33(5):1307-17. DOI: 10.1007/s13277-012-0378-3
Source: PubMed


Aberrant DNA methylation has been implicated in the development of hepatocellular carcinoma (HCC). Our aim was to clarify its molecular mechanism and to identify useful biomarkers by screening for DNA methylation in HCC. Methylated CpG island amplification coupled with CpG island microarray (MCAM) analysis was carried out to screen for methylated genes in primary HCC specimens [hepatitis B virus (HBV)-positive, n = 4; hepatitis C virus (HCV)-positive, n = 5; HBV/HCV-negative, n = 7]. Bisulfite pyrosequencing was used to analyze the methylation of selected genes and long interspersed nuclear element (LINE)-1 in HCC tissue (n = 57) and noncancerous liver tissue (n = 50) from HCC patients and in HCC cell lines (n = 10). MCAM analysis identified 332, 342, and 259 genes that were methylated in HBV-positive, HCV-positive, and HBV/HCV-negative HCC tissues, respectively. Among these genes, methylation of KLHL35, PAX5, PENK, and SPDYA was significantly higher in HCC tissue than in noncancerous liver tissue, irrespective of the hepatitis virus status. LINE-1 hypomethylation was also prevalent in HCC and correlated positively with KLHL35 and SPDYA methylation. Receiver operating characteristic curve analysis revealed that methylation of the four genes and LINE-1 strongly discriminated between HCC tissue and noncancerous liver tissue. Our data suggest that aberrant hyper- and hypomethylation may contribute to a common pathogenesis mechanism in HCC. Hypermethylation of KLHL35, PAX, PENK, and SDPYA and hypomethylation of LINE-1 could be useful biomarkers for the detection of HCC.

1 Follower
20 Reads
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatocellular carcinoma (HCC) incidence has increased in the US and also has one of the fastest growing death rates of any cancer. The purpose of the current study was to discover novel genome-wide aberrant DNA methylation patterns in HCC tumors that are predominantly HCV-related. Infinium HumanMethylation 450K BeadChip arrays were used to examine genome-wide DNA methylation profiles in 66 pairs of HCC tumor and adjacent non-tumor tissues. After Bonferroni adjustment, a total of 130,512 CpG sites significantly differed in methylation level in tumor compared with non-tumor tissues, with 28,017 CpG sites hypermethylated and 102,495 hypomethylated in tumor tissues. Absolute tumor/non-tumor methylation differences ≥ 20% were found in 24.9% of the hypermethylated and 43.1% of the hypomethylated CpG sites; almost 10,000 CpG sites have ≥ 30% DNA methylation differences. Most (60.1%) significantly hypermethylated CpG sites are located in CpG islands, with 21.6% in CpG shores and 3.6% in shelves. In contrast, only a small proportion (8.2%) of significantly hypomethylated CpG sites are situated in islands, while most are found in open sea (60.2%), shore (17.3%) or shelf (14.3%) regions. A total of 2,568 significant CpG sites (2,441 hypermethylated and 127 hypomethylated) covering 520 genes are located within differentially methylated regions defined as regions with at least two significant CpG sites displaying > 20% methylation differences in the same direction within 250-bp. The top 500 significant CpG sites can significantly distinguish HCC tumor from adjacent tissues with one misclassification. Within adjacent non-tumor tissues, we also identified 75 CpG sites significantly associated with gender, 228 with HCV infection, 17,207 with cirrhosis, and 56 with both HCV infection and cirrhosis after multiple comparisons adjustment. Aberrant DNA methylation profiles across the genome were identified in tumor tissues from US HCC cases that are predominantly related to HCV infection. These results demonstrate the significance of aberrant DNA methylation in HCC tumorigenesis.
    Full-text · Article · Dec 2012 · Epigenetics: official journal of the DNA Methylation Society
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: From May 16-19, 2012, the International Liver Transplantation Society held its annual congress in San Francisco, CA. More than 1300 registrants attended the meeting, which included a premeeting conference entitled Balancing Risk in Liver Transplantation, focused topic sessions, and a variety of oral and poster presentations. This report is not all-inclusive and focuses on specific research abstracts on key topics in liver transplantation. As always, the new data herein are presented in the context of the published literature to further enhance knowledge in the field. Liver Transpl, 2012. © 2012 AASLD.
    Full-text · Article · Jan 2013 · Liver Transplantation
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purposes of this study were to evaluate the infection by hepatitis B virus (HBV) and its impact on survival and to provide a clinical reference for monitoring and treating HBV during and after autologous hematopoietic stem cell transplantation (ASCT) in patients with multiple myeloma (MM). A retrospective analysis of HBV infections was performed in 70 MM patients who received a sequential bortezomib-containing induction therapy and ASCT in our department from June 2006 to February 2012. Among the 70 patients in our study, 11 cases (15.7 %) were hepatitis B surface antigen positive (HBsAg+), and 23 cases (33.3 %) were hepatitis B core antibody positive (HBcAb+). Eight cases were HBsAg, hepatitis B e antibody (HBeAb), and HBcAb positive, while one case was HBsAg, hepatitis B e antigen (HBeAg), and HBcAb positive. The median follow-up times for the HBsAg+ group and the HBsAg-negative (HBsAg-) group were 27.0 (7.6-85.2) months and 28.7 (7.1-111.0) months, respectively. The 1-year, 2-year, and 3-year overall survival rates of the HBsAg+ group were 90.9, 80.8, and 34.6 %, respectively, and the median survival time was 31.2 months (95 % CI, 24.8-37.6). The 1-year, 2-year, and 3-year overall survival rates of the HBsAg- group were 98.2, 94, and 84.6 %, respectively, while the median survival time was not yet available. There was a statistically significant difference (p = 0.008) in the overall survival rate between the two groups. By Cox regression analysis, we found that the HBsAg+ status was a prognostic factor, which could independently influence the overall survival rate for ASCT. In conclusion, the HBsAg+ status is an independent risk factor for patients with MM receiving ASCT. The application of standard antiviral treatment might help to overcome this risk factor.
    No preview · Article · Feb 2013 · Tumor Biology
Show more