title: Angiotensin-converting enzyme insertion/deletion gene polymorphism and lung cancer risk: A meta-analysis.
abstract: OBJECTIVE
  Angiotensin-converting enzyme (ACE) I/D polymorphism has been reported to be associated with lung cancer, but the results of previous studies are conflicting. The present study was designed to investigate the association between this polymorphism and the risk of lung cancer using a meta-analysis of the published studies.
  
  
  METHODS
  Two investigators independently searched the PubMed, Embase and CNKI databases. This meta-analysis covered six case-control studies, including 807 lung cancer patients and 816 healthy controls.
  
  
  RESULTS
  The results of this meta-analysis based on all the studies showed no significant association between ACE I/D gene polymorphism and lung cancer risk (DD vs II: OR = 1.18, 95% CI = 0.68-2.04; DI vs II: OR = 0.93, 95% CI = 0.56-1.53; DD+DI vs II: OR = 1.01, 95% CI = 0.68-1.50; DD vs II+DD: OR =1.11, 95% CI = 0.73-1.71). In the subgroup analysis by race and the larger studies (n > 200 participants), no significant associations between the ACE I/D polymorphism and risk of lung cancer were indicated. However, when the analyses were restricted to small studies (n ≤ 200 participants), a significantly higher risk was observed (DD vs II: OR = 2.57, 95% CI = 1.24-5.30).
  
  
  CONCLUSIONS
  This meta-analysis suggests that the ACE gene I/D polymorphism may not be associated with the risk of lung cancer, and the observed increase in the risk of lung cancer may be due to small-study bias.
authors.affiliation: Medical Department, Huzhou Traditional Chinese Medicine Hospital, People's Republic of China.
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.affiliation: Medical Department, Huzhou Traditional Chinese Medicine Hospital, People's Republic of China.
authors.forename: DaFu
authors.initials: D
authors.lastname: Yang
authors.affiliation: Medical Department, Huzhou Traditional Chinese Medicine Hospital, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Ji
authors.affiliation: Medical Department, Huzhou Central Hospital, People's Republic of China lijianyou120@126.com.
authors.forename: JianYou
authors.initials: J
authors.lastname: Li
mesh_terms: D017353:Gene Deletion; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D016254:Mutagenesis, Insertional / Q000235:genetics*; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D018570:Risk Assessment
chemical_list: C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A
keywords: ACE; gene polymorphism; lung cancer; meta-analysis