LINE-1 hypomethylation is not a common event in preneoplastic stages of gastric carcinogenesis

Sci Rep. 2017 Jul 6;7(1):4828. doi: 10.1038/s41598-017-05143-0.

Abstract

LINE-1 hypomethylation is widely accepted as marker for global genomic DNA hypomethylation, which is a frequent event in cancer. The aim of the study was to evaluate LINE-1 methylation status at different stages of gastric carcinogenesis and evaluate its prognostic potential in clinical settings. LINE-1 methylation was analyzed in 267 tissue samples by bisulfite pyrosequencing including primary colorectal cancer tissues (T-CRC) with corresponding adjacent colon mucosa (N-CRC), gastric cancer tissues (T-GC) with corresponding gastric mucosa (N-GC), normal gastric tissues (N), chronic non-atrophic and atrophic gastritis (CG). LINE-1 methylation level was lower in both T-GC and T-CRC when compared to paired adjacent tissues. No difference was observed for LINE-1 methylation status between patients with normal gastric mucosa, CG and N-GC. LINE-1 methylation in T-GC but not N-GC tended to correlate with age. Subgroup stratification analysis did not reveal significant differences in LINE-1 methylation status according to tumor stage, anatomical location, histological subtype, differentiation grade. We observed similar overall survival data between patients with high or low LINE-1 levels. In summary, LINE-1 hypomethylation is a characteristic feature in GC but not very common in early preneoplastic stages of gastric carcinogenesis. Prognostic role of LINE-1 hypomethylation in GC patients could not be confirmed in this cohort.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Carcinogenesis / genetics*
  • Carcinogenesis / metabolism
  • Carcinogenesis / pathology
  • Case-Control Studies
  • Colorectal Neoplasms / diagnosis
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / pathology
  • DNA Methylation*
  • Epigenesis, Genetic*
  • Female
  • Gastric Mucosa / metabolism
  • Gastric Mucosa / pathology
  • Gastritis, Atrophic / diagnosis
  • Gastritis, Atrophic / genetics*
  • Gastritis, Atrophic / mortality
  • Gastritis, Atrophic / pathology
  • Humans
  • Long Interspersed Nucleotide Elements*
  • Male
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Prognosis
  • Stomach Neoplasms / diagnosis
  • Stomach Neoplasms / genetics*
  • Stomach Neoplasms / mortality
  • Stomach Neoplasms / pathology
  • Survival Analysis