title: The associations between five polymorphisms of vascular endothelial growth factor and renal cell carcinoma risk: an updated meta-analysis.
abstract: BACKGROUND
  Vascular endothelial growth factor (VEGF) is a key mediator that plays an important role in angiogenesis, tumor growth, and tumor metastasis. The associations between five polymorphisms of VEGF (rs3025039, rs699947, rs10434, rs1570360, and rs2010963) and renal cell carcinoma (RCC) risk have been extensively investigated, but the currently available results are inconsistent and inconclusive. To obtain a more accurate assessment of the associations, we conducted a meta-analysis in this study.
  
  
  METHODS
  Relevant studies were collected systemically from the following three electronic databases: MEDLINE, Web of Science, and CNKI (Chinese National Knowledge Infrastructure). Statistical analyses were performed using Review Manager 5.2 in a fixed- or random-effects model. Pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to establish the strength of associations.
  
  
  RESULTS
  A total of eight case-control studies with 1,936 RCC cases and 2,770 controls fulfilling the inclusion criteria were selected for this meta-analysis. The pooled OR indicated that rs699947 polymorphism was significantly associated with RCC risk in all genetic models. A significant association was also found between the rs3025039 polymorphism and RCC risk in a homozygous model (TT vs CC: OR =1.38, 95% CI =1.11-1.72,P=0.004), a dominant model (CT+TT vs CC: OR =1.21, 95% CI =1.05-1.39,P=0.01), and a recessive model (TT vs CC+CT: OR =1.28, 95% CI =1.04-1.57,P=0.02). After a subgroup analysis of ethnicity in the allele contrast model of rs3025039 polymorphism, we found a significant relationship in the allele contrast model (T vs C: OR =1.21, 95% CI =1.05-1.40,P=0.007) in the Asian population. With regard to rs10434 polymorphism, significant association was observed only in a homozygous model (GG vs AA: OR =0.75, 95% CI =0.57-0.98,P=0.03). As to rs1570360 or rs2010963, we did not observe any relationship between the two polymorphisms and RCC risk in our study.
  
  
  CONCLUSIONS
  Our meta-analysis confirmed the fact that rs699947, rs3025039, and rs10434 polymorphisms were significantly relevant to elevated RCC risk. In the meanwhile, this study also demonstrated that the allele contrast model of rs3025039 polymorphism was likely to be associated with risk of RCC in the Asian population.
authors.affiliation: Genetic Diagnosis Center.
authors.forename: Jiao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Genetic Diagnosis Center.
authors.forename: ChangXin
authors.initials: C
authors.lastname: Shen
authors.affiliation: Blood Transfusion Department, Zhongnan Hospital of Wuhan University, Wuhan, People's Republic of China.
authors.forename: YouRong
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Blood Transfusion Department, Zhongnan Hospital of Wuhan University, Wuhan, People's Republic of China.
authors.forename: Tian
authors.initials: T
authors.lastname: Yu
authors.affiliation: Genetic Diagnosis Center.
authors.forename: JingJing
authors.initials: J
authors.lastname: Song
keywords: meta-analysis; polymorphism; renal cell carcinoma; vascular endothelial growth factor