Genome-wide DNA methylation analyses in lung adenocarcinomas: Association with EGFR, KRAS and TP53 mutation status, gene expression and prognosis

Mol Oncol. 2016 Feb;10(2):330-43. doi: 10.1016/j.molonc.2015.10.021. Epub 2015 Nov 6.


Background: DNA methylation alterations are early events in tumorigenesis and important in the regulation of gene expression in cancer cells. Lung cancer patients have in general a poor prognosis, and a deeper insight into the epigenetic landscape in lung adenocarcinoma tumors and its prognostic implications is needed.

Results: We determined whole-genome DNA methylation profiles of 164 fresh frozen lung adenocarcinoma samples and 19 samples of matched normal lung tissue using the Illumina Infinium 450K array. A large number of differentially methylated CpGs in lung adenocarcinoma tissue were identified, and specific methylation profiles were observed in tumors with mutations in the EGFR-, KRAS- or TP53 genes and according to the patients' smoking status. The methylation levels were correlated with gene expression and both positive and negative correlations were seen. Methylation profiles of the tumor samples identified subtypes of tumors with distinct prognosis, including one subtype enriched for TP53 mutant tumors. A prognostic index based on the methylation levels of 33 CpGs was established, and was significantly associated with prognosis in the univariate analysis using an independent cohort of lung adenocarcinoma patients from The Cancer Genome Atlas project. CpGs in the HOX B and HOX C gene clusters were represented in the prognostic signature.

Conclusions: Methylation differences mirror biologically important features in the etiology of lung adenocarcinomas and influence prognosis.

Keywords: 450K; Adenocarcinoma; CpG; DNA methylation; EGFR; KRAS; LUAD; Lung cancer; NSCLC; Prognosis; TP53; mRNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics*
  • Adenocarcinoma of Lung
  • Adult
  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • CpG Islands
  • DNA Methylation*
  • ErbB Receptors / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Genes, Homeobox
  • Genome, Human
  • Humans
  • Lung Neoplasms / genetics*
  • Male
  • Middle Aged
  • Mutation
  • Norway / epidemiology
  • Prognosis
  • Proto-Oncogene Proteins p21(ras) / genetics*
  • RNA, Messenger / metabolism*
  • Signal Transduction
  • Smoking / adverse effects
  • Smoking / genetics
  • TOR Serine-Threonine Kinases / metabolism
  • Tumor Suppressor Protein p53 / genetics*


  • KRAS protein, human
  • RNA, Messenger
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • MTOR protein, human
  • TOR Serine-Threonine Kinases
  • EGFR protein, human
  • ErbB Receptors
  • Proto-Oncogene Proteins p21(ras)