title: Prostaglandin-endoperoxide synthase 2 (PTGS2) rs20417 polymorphism and prostate cancer risk: a meta analysis.
abstract: BACKGROUND
  Genetic variation of SNPs in the PTGS2 gene is reported to be capable of creating tissue milieu favoring tumorigenesis. Some studies have implicated the common SNP rs20417 has association with PCa risk, while others showed reverse results. The study was performed with an aim to reconcile the existing controversy by performing a meta-analysis.
  
  
  METHODS
  We searched databases of Embase and PubMed and identified 8 publications fulfilling the specified inclusion criteria. X(2)-based Q-test and I(2) statistic were quantified to measure the heterogeneity across studies. The pooled ORs and 95% CIs were calculated to estimate the association between SNP rs20417 and PCa risk.
  
  
  RESULTS
  Based on an enlarged sample size by combining the data from published meta-analyses and those missed in them, the results of the present meta-analysis revealed the association of SNP rs20417 and overall PCa risk was not significant. Subgroup analyses according to ethnicity and source of controls did not show any significant results, either.
  
  
  CONCLUSIONS
  The meta-analysis suggests that the presence of SNP rs20417 is unlikely to be associated with PCa risk. Our understanding of the genetic risk for PCa should be further expanded and refined through future research in a much larger number of participants.
authors.affiliation: Department of Urology, Chinese PLA General Hospital Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Urology, Chinese PLA General HospitalBeijing, China; Department of Urology, 305 Hospital of PLABeijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Urology, Chinese PLA General Hospital Beijing, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Urology, Chinese PLA General Hospital Beijing, China.
authors.forename: Baofa
authors.initials: B
authors.lastname: Hong
keywords: PTGS2; polymorphism; prostate cancer; rs20417