title: The Association Between MGMT Promoter Methylation and Patients with Gastric Cancer: A Meta-Analysis.
abstract: OBJECTIVE
  Several previous studies have suggested that MGMT promoter methylation is significantly associated with gastric cancer, but the results were not consistent. Hence, we conducted a systematic meta-analysis to explore the potential correlation of MGMT promoter methylation with gastric cancer and its clinicopathologic characteristics.
  
  
  METHODS
  Searches of PubMed, EMBASE, Web of Science, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI) literature databases were conducted to identify relevant studies published in English or Chinese before July 1, 2016. The meta-analysis was performed using Stata 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the association between MGMT promoter methylation and gastric cancer. We also conducted a subgroup analysis and metaregression to explore sources of heterogeneity.
  
  
  RESULTS
  We identified 12 articles that met the inclusion criteria. The 12 articles described 14 studies that included 1571 tumor tissues and 1243 controls. The meta-analysis results demonstrated that the frequency of MGMT promoter methylation was higher in gastric cancer tissues compared with adjacent tissues and normal tissues (OR = 4.06, 95% CI: 2.55-6.46, p < 0.001; OR = 8.85, 95% CI: 1.15-68.23, p = 0.036; respectively). An assessment of the correlation between MGMT promoter methylation and clinicopathological characteristics indicated that MGMT promoter hypermethylation was significantly associated with tumor-node-metastasis stage, lymph node metastasis, and distant metastasis (OR = 2.11, 95% CI: 1.18-3.75, p = 0.011; OR = 1.99, 95% CI: 1.47-2.68, p < 0.001; and OR = 3.60, 95% CI: 2.17-5.95, p < 0.001; respectively).
  
  
  CONCLUSIONS
  Our findings provide evidence that MGMT promoter methylation could play an important role in gastric carcinogenesis and may serve as an important biomarker for gastric cancer progression.
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Yuan
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Jifei
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Weiyang
authors.initials: W
authors.lastname: Fang
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Fan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University , Hefei, People's Republic of China .
authors.forename: Zhuting
authors.initials: Z
authors.lastname: Tong
mesh_terms: D044466:Asian People; D014408:Biomarkers, Tumor; D016022:Case-Control Studies; D019175:DNA Methylation / Q000235:genetics; D015254:DNA Modification Methylases / Q000235:genetics* / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics; D008297:Male; D009362:Neoplasm Metastasis / Q000235:genetics; D016017:Odds Ratio; D011401:Promoter Regions, Genetic / Q000235:genetics; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000235:genetics*; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D025521:Tumor Suppressor Proteins; D015254:DNA Modification Methylases; C515491:MGMT protein, human; D045643:DNA Repair Enzymes
keywords: DNA methylation; MGMT; gastric cancer