title: Methylenetetrahydrofolate reductase 677TT genotype may be associated with an increased lung cancer risk in North China: an updated meta-analysis.
abstract: BACKGROUND
  Although many epidemiology studies have investigated the methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and their associations with lung cancer (LC), definite conclusions cannot be drawn. To clarify the effects of MTHFR polymorphisms on the risk of LC, we performed a meta-analysis in Chinese populations.
  
  
  METHODS
  Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) until 16 February 2014. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations.
  
  
  RESULTS
  A total of 11 studies with 2487 LC cases and 3228 controls were included in this meta-analysis. Overall, no significant association was found between MTHFR C677T polymorphism and LC risk when all studies in Chinese populations were pooled into this meta-analysis. In subgroup analyses stratified by geographical location and source of controls, significantly increased risk was found in North China (T vs. C: OR=1.28, 95% CI: 1.14-1.44; TT vs. CC: OR=1.67, 95% CI: 1.33-2.10; TT + CT vs. CC, OR=1.39, 95% CI=1.15-1.69; TT vs. CC + CT: OR=1.46, 95% CI: 1.03-2.06) and in population-based studies (TT vs. CC: OR=1.37, 95% CI: 1.14-1.65; TT vs. CC + CT: OR=1.25, 95% CI: 1.07-1.45).
  
  
  CONCLUSIONS
  This meta-analysis provides evidence that MTHFR C677T polymorphism may contribute to LC development in North China. Studies with larger sample sizes and wider spectrum of populations are warranted to verify this finding.
authors.affiliation: Department of Thoracic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Nan-Bo
authors.initials: NB
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, Third Affiliated Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Thoracic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Qi
authors.affiliation: Department of Thoracic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Zhen-Zhong
authors.initials: ZZ
authors.lastname: Zhang
authors.affiliation: Department of Thoracic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Xu
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China (mainland).
authors.forename: Jun-Hua
authors.initials: JH
authors.lastname: Zhang
mesh_terms: D002681:China; D016001:Confidence Intervals; D020022:Genetic Predisposition to Disease; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017594:Publication Bias; D012307:Risk Factors
chemical_list: C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)