title: Global DNA methylation and tumor suppressor gene promoter methylation and gastric cancer risk in an Omani Arab population.
abstract: OBJECTIVE
  We carried out a case-control study in an Omani Arab population to investigate the association between gastric cancer and peripheral blood leukocyte DNA methylation in LINE-1 and in the tumor suppressor genes CDH1, p16, TP53 and RUNX3.
  
  
  METHODS
  We quantified methylation (%5-mC) in DNA extracted from peripheral blood leukocytes via pyrosequencing. We calculated odds ratios (ORs) and 95% CIs using logistic regression.
  
  
  RESULTS
  We found patterns of global hypomethylation (LINE-1: OR(continuous) = 0.59; 95% CI: 0.42-0.82) and TP53 promoter hypomethylation (OR(continuous) = 0.64; 95% CI: 0.16-0.85) for cases versus controls; p16 promoter region hypomethylation was not statistically significant. Evaluating LINE-1, TP53 and p16 jointly yielded a more pronounced negative association with gastric cancer (OR: 0.24; 95% CI: 0.09-0.66). Age was a significant effect modifier. We found no differences by tumor grade, stage or histology.
  
  
  CONCLUSIONS
  We found a pattern of global hypomethylation and promoter region hypomethylation of TP53 and p16 in cases versus controls for this population of Omani Arabs.
authors: Department of Preventive Medicine & Biometrics, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA. jrusiecki@usuhs.mil
authors: Jennifer A
authors: JA
authors: Rusiecki
authors: Maryam
authors: M
authors: Al-Nabhani
authors: Letizia
authors: L
authors: Tarantini
authors: Ligong
authors: L
authors: Chen
authors: Andrea
authors: A
authors: Baccarelli
authors: Mansour S
authors: MS
authors: Al-Moundhri
mesh_terms: D015703:Antigens, CD; D018912:Arabs / Q000235:genetics; D015820:Cadherins / Q000502:physiology; D016022:Case-Control Studies; D050677:Core Binding Factor Alpha 3 Subunit / Q000502:physiology; D019941:Cyclin-Dependent Kinase Inhibitor p16; D019175:DNA Methylation / Q000502:physiology*; D016147:Genes, Tumor Suppressor; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D016015:Logistic Models; D020084:Long Interspersed Nucleotide Elements / Q000502:physiology*; D009363:Neoplasm Proteins / Q000502:physiology; D016017:Odds Ratio; D009850:Oman; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000502:physiology*; D018570:Risk Assessment; D017422:Sequence Analysis, DNA / Q000379:methods; D013274:Stomach Neoplasms / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; C000614131:CDKN2A protein, human; D015820:Cadherins; D050677:Core Binding Factor Alpha 3 Subunit; D019941:Cyclin-Dependent Kinase Inhibitor p16; D009363:Neoplasm Proteins; C493729:Runx3 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53