title: Vascular endothelial growth factor (VEGF) gene polymorphisms and colorectal cancer: a meta-analysis of epidemiologic studies.
abstract: BACKGROUND
  Studies investigating the association between vascular endothelial growth factor (VEGF) polymorphisms and colorectal cancer (CRC) risk report conflicting results. To clarify the effect of four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms on the risk of developing CRC, we carried out a meta-analysis using published data to obtain more precise estimates of risk.
  
  
  METHODS
  Electronic searches of PubMed and EMBASE were conducted to select studies for this meta-analysis. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of CRC associated with four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms.
  
  
  RESULTS
  We identified 12 epidemiologic studies, which included 2770 CRC cases and 2568 controls. The combined results based on all studies showed that CRC cases had a significantly higher frequency of VEGF -634GG (OR=1.24, 95% CI=1.06, 1.44) and -2578AA (OR=1.37, 95% CI=1.12, 1.66) genotype and a lower frequency of -634CG (OR=0.82, 95% CI=0.71, 0.95) than controls. When stratifying for race, we found that patients with CRC had a significantly higher frequency of -460TC (OR=1.54, 95% CI=1.22, 1.94), -460CC (OR=2.00, 95% CI=1.50, 2.67), and -2578AA (OR=1.38, 95% CI=1.12, 1.69) and a lower frequency of -2578AA (OR=0.78, 95% CI=0.65, 0.93) genotypes of VEGF than controls, among Caucasians. We also found that patients with CRC had a significantly higher frequency of -634GG (OR=1.61, 95% CI=1.20, 2.15) and a lower frequency of -634CG (OR=0.60, 95% CI=0.46, 0.79) genotypes of VEGF than controls, among Asians.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that the VEGF -460T/C, -634G/C, and -2578C/A gene polymorphisms are associated with a risk of CRC.
authors.affiliation: Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu, PR China.
authors.forename: Zigang
authors.initials: Z
authors.lastname: Zhao
authors.forename: Caixia
authors.initials: C
authors.lastname: Ba
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Ruizeng
authors.initials: R
authors.lastname: Xue
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Wu
mesh_terms: D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D016021:Epidemiologic Studies; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
chemical_list: C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A