title: The relationship between angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive cancer risk: Insights from a meta-analysis.
abstract: OBJECTIVE
  The gene encoding angiotensin-converting enzyme (ACE) has been implicated in the development of several malignancies. We aimed to meta-analyze the association of ACE gene insertion/deletion (I/D) polymorphism with digestive cancer risk and seek possible sources of between-study heterogeneity.
  
  
  METHODS
  Two authors independently assessed eligibility of each retrieved publication and gathered relevant data. Risk estimates were expressed as odds ratio (OR) and 95% confidence interval (CI).
  
  
  RESULTS
  Sixteen publications were qualified for analysis, involving 2903 digestive cancer cases and 10,833 controls. Overall analyses failed to show any significance for digestive cancer risk. There was moderate heterogeneity and lower publication bias for overall comparisons. In subgroup analyses, ACE gene II genotype was associated with a 15% reduced risk (OR=0.85, 95% CI: 0.57-1.27, p=0.434) for gastric cancer, but a 16% increased risk (OR=1.16, 95% CI: 0.89-1.52, p=0.273) for colorectal cancer. By source of controls, the I allele appeared to be a protective factor against digestive cancer in population-based studies (OR=0.87, 95% CI: 0.75-1.00, p=0.055) but a risk-conferring factor in hospital-based studies (OR=1.17, 95% CI: 1.01-1.35, p=0.033).
  
  
  CONCLUSIONS
  Our findings suggested that ACE gene I allele might be a protective factor against gastric cancer, necessitating further confirmation in large, population-based studies.
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Hualing
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Chengfu
authors.initials: C
authors.lastname: Cai
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Linyang
authors.initials: L
authors.lastname: Ye
authors.affiliation: Department of Hematology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Yiqing
authors.initials: Y
authors.lastname: Rao
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Pathology, Fujian Provincial Tumor Hospital, Teaching Hospital of Fujian Medical University, Fuzhou, Fujian, China Fujian Provincial Key Laboratory of Translational Center Medicine, Fujian Provincial Tumor Hospital, Teaching Hospital of Fujian Medical University, Fuzhou, Fujian, China hudanfuzhou@yeah.net.
authors.forename: Dan
authors.initials: D
authors.lastname: Hu
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Huang
mesh_terms: D000368:Aged; D000483:Alleles; D004067:Digestive System Neoplasms / Q000201:enzymology* / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D054643:INDEL Mutation / Q000235:genetics*; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic; D017594:Publication Bias; D012044:Regression Analysis; D012307:Risk Factors
chemical_list: C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A
keywords: Angiotensin-converting enzyme; digestive cancer; meta-analysis; polymorphism