title: Relation between normal rectal methylation, smoking status, and the presence or absence of colorectal adenomas.
abstract: BACKGROUND
  Colorectal cancer (CRC) is 1 of the leading causes of death in the Western world. CRC develops from premalignant lesions, chiefly colorectal adenomas. Currently, the most accurate and recommended screening method for finding colorectal adenomas is colonoscopy performed on all individuals aged>50 years. However, the costs and risks associated with this procedure are relatively high. The objectives of the current study were to correlate epigenetic alterations that occur in normal rectal mucosa, smoking status, and age with the presence or absence of concomitant colorectal adenomas and to assess the potential clinical value of methylation in normal rectal biopsies as a screening assay for the presence of polyps and, hence, the need for a full colonoscopy.
  
  
  METHODS
  One hundred thirteen normal rectal mucosal biopsies from 113 patients were studied. DNA was extracted, modified with sodium bisulfite, and subjected to real-time quantitative, methylation-specific polymerase chain reaction analysis for the following genes: adenomatous polyposis coli (APC); cadherin 1, type 1, E-cadherin (epithelial) (CDH1); estrogen receptor 1 (ESR1); cytokine high in normal 1 (HIN1); hyperplastic polyposis protein 1 (HPP1); O-6 methylguanine-DNA methyltransferase (MGMT); neural epidermal growth factor-like 1 (NELL1); splicing factor 3B, 14-kDa subunit (p14); cyclin-dependent kinase (CDK) inhibitor 2B (inhibits CDK4) (p15); retinoic acid receptor beta (RARβ); somatostatin (SST); tachykinin, precursor 1 (TAC1); and tissue inhibitor of metalloproteinase (TIMP) metallopeptidase inhibitor 3 (TIMP3). Data were then analyzed using several proprietary software programs.
  
  
  RESULTS
  By using several sets of genes, clinical characteristics, and multivariate analyses, the authors developed a prediction model for the presence of concomitant colorectal adenomas at the time of rectal biopsy. They also observed strong correlations between smoking status and rectal methylation pattern and between smoking status and the presence or risk of concomitant adenomas.
  
  
  CONCLUSIONS
  A prediction model was developed for the presence of colorectal adenomas based on gene methylation patterns in the normal rectum. The results indicated that these genes may be involved in early stages of adenoma formation. The observed epigenetic alterations in these markers may be caused in part by the effects of smoking and/or age. Normal rectal methylation may be useful as a biomarker for narrowing the population in need of screening colonoscopy.
authors.affiliation: Division of Gastroenterology, Department of Medicine, the Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
authors.forename: Bogdan C
authors.initials: BC
authors.lastname: Paun
authors.forename: Debra
authors.initials: D
authors.lastname: Kukuruga
authors.forename: Zhe
authors.initials: Z
authors.lastname: Jin
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Mori
authors.forename: Yulan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Mark
authors.initials: M
authors.lastname: Duncan
authors.forename: Sanford A
authors.initials: SA
authors.lastname: Stass
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Montgomery
authors.forename: David
authors.initials: D
authors.lastname: Hutcheon
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Meltzer
mesh_terms: D000236:Adenoma / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012007:Rectum / Q000378:metabolism*; D012306:Risk; D012907:Smoking