title: Long interspersed nucleotide element 1 hypomethylation is associated with poor prognosis of lung adenocarcinoma.
abstract: BACKGROUND
  Genome-wide DNA hypomethylation is known to play important roles in genomic instability and carcinogenesis. Methylation in long interspersed nucleotide element 1 (LINE-1) is a good indicator of the global DNA methylation level within a cell. The aim of this study was to evaluate prognostic significance of LINE-1 hypomethylation in lung adenocarcinoma.
  
  
  METHODS
  A consecutive series of 211 lung adenocarcinoma patients who underwent curative resections without any preoperative chemotherapy or radiotherapy at Kumamoto University Hospital between April 2010 and December 2012 were included. The LINE-1 methylation levels were quantified in tumor and noncancerous tissue by Pyrosequencing assay.
  
  
  RESULTS
  Higher histologic grade and positive findings for vascular invasion were significantly associated with lower methylation levels. The disease-free survival in the hypomethylation group was significantly shorter than that of the non-hypomethylation group. The prognostic difference was more obvious in advanced cases (stage II, III) than in stage I cases.
  
  
  CONCLUSIONS
  The LINE-1 methylation level is associated with histologic grade and vascular invasion of lung adenocarcinoma. Additionally, LINE-1 hypomethylation is a useful biomarker to predict early recurrence of lung adenocarcinoma.
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medical Science, Kumamoto University, Kumamoto, Japan. Electronic address: koei@cg7.so-net.ne.jp.
authors.forename: Koei
authors.initials: K
authors.lastname: Ikeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Ayami
authors.initials: A
authors.lastname: Eguchi
authors.forename: Hidekatsu
authors.initials: H
authors.lastname: Shibata
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mori
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Baba
authors.forename: Hideo
authors.initials: H
authors.lastname: Baba
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D000077192:Adenocarcinoma of Lung; D000368:Aged; D019175:DNA Methylation; D005260:Female; D006801:Humans; D020084:Long Interspersed Nucleotide Elements; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D011379:Prognosis
keywords: 10