Annals of Surgical Oncology

, Volume 22, Issue 4, pp 1280–1287 | Cite as

LINE-1 Methylation Level and Patient Prognosis in a Database of 208 Hepatocellular Carcinomas

  • Kazuto Harada
  • Yoshifumi Baba
  • Takatsugu Ishimoto
  • Akira Chikamoto
  • Keisuke Kosumi
  • Hiromitsu Hayashi
  • Hidetoshi Nitta
  • Daisuke Hashimoto
  • Toru Beppu
  • Hideo Baba
Gastrointestinal Oncology



The level of long interspersed nucleotide element-1 (LINE-1) methylation has become regarded as a surrogate marker of global DNA methylation. Previously, we demonstrated that LINE-1 hypomethylation might contribute to the acquisition of aggressive tumor behavior through genomic gains of oncogenes such as cyclin-dependent kinase 6 (CDK6) in esophageal squamous cell carcinoma. However, the relationship between LINE-1 hypomethylation and clinical outcome in hepatocellular carcinoma (HCC) remains unclear.


LINE-1 methylation level in 208 samples of curatively resected HCCs was measured by pyrosequencing assay, and the prognostic value of LINE-1 methylation level in HCC was examined.


LINE-1 methylation levels in the 208 HCC patients investigated were distributed as follows: mean 64.7; median 64.6; standard deviation (SD) 13.6; range 21.5–99.1; interquartile range 62.9–66.6. Univariate Cox regression analysis revealed a significantly higher cancer recurrence rate in the low-methylation-level group than in the high-methylation-level group (hazard ratio 1.58; 95 % CI 1.05–2.47; p = 0.028). Interestingly, the influence of LINE-1 hypomethylation on patient outcome was modified by hepatitis virus infection (p of interaction = 0.023); LINE-1 hypomethylation was associated with a higher cancer recurrence rate in patients without hepatitis virus infection (log-rank p = 0.0047). CDK6 messenger RNA expression levels were inversely associated with LINE-1 methylation levels (p = 0.0075; R = −0.37).


Genome-wide DNA hypomethylation, as measured by LINE-1 levels, might be associated with poor disease-free survival in HCC patients, suggesting a potential role for LINE-1 methylation level as a biomarker for identifying patients who will experience an unfavorable clinical outcome.



Author contributions: conception and design: Kazuto Harada, Yoshifumi Baba, Toru Beppu, and Hideo Baba; acquisition of data: Kazuto Harada, Yoshifumi Baba, and Toru Beppu; analysis and interpretation of data: Kazuto Harada and Yoshifumi Baba; manuscript writing: Kazuto Harada, Yoshifumi Baba, and Hideo Baba. All authors approved the final manuscript.

Conflict of interest

No conflicts of interest exist.

Supplementary material

10434_2014_4134_MOESM1_ESM.tif (768 kb)
Kaplan–Meier curves for the study group (red) and excluded group (blue). The left and right panels show theoverall survival rate and the disease-free survival rate, respectively (TIFF 768 kb)
10434_2014_4134_MOESM2_ESM.tif (2 mb)
The pyrosequencing assay used to measure the LINE-1 methylation level. The overall LINE-1methylationlevel is the average proportion of C (%) at the 4 CpG sites. The percentages of C at each CpG site afterbisulfite conversion, used to compute the methylation level at each CpG site, are given in blue font. Upperand lower panels show the results for LINE-1 hypermethylated tumor (methylation level, 81.5%) and LINE-1hypomethylated tumor (methylation level, 48.3%), respectively (TIFF 2064 kb)
10434_2014_4134_MOESM3_ESM.docx (25 kb)
Supplementary material 3 (DOCX 25 kb)
10434_2014_4134_MOESM4_ESM.docx (25 kb)
Supplementary material 4 (DOCX 24 kb)


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Copyright information

© Society of Surgical Oncology 2014

Authors and Affiliations

  • Kazuto Harada
    • 1
  • Yoshifumi Baba
    • 1
  • Takatsugu Ishimoto
    • 1
  • Akira Chikamoto
    • 1
  • Keisuke Kosumi
    • 1
  • Hiromitsu Hayashi
    • 1
  • Hidetoshi Nitta
    • 1
  • Daisuke Hashimoto
    • 1
  • Toru Beppu
    • 1
  • Hideo Baba
    • 1
  1. 1.Department of Gastroenterological Surgery, Graduate School of Medical ScienceKumamoto UniversityKumamotoJapan

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