title: Association between manganese superoxide dismutase (MnSOD) polymorphism and prostate cancer susceptibility: a meta-analysis.
abstract: BACKGROUND
  Previous studies have investigated the relationship between manganese superoxide dismutase (MnSOD) Val16Ala polymorphism and prostate cancer susceptibility, but the results have remained controversial. This meta-analysis was therefore performed to clarify this association.
  
  
  METHODS
  The databases PubMed, Embase and Web of Science were searched for relevant available studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the strength of the association. Publication bias was estimated using Begg's funnel plots and Egger's regression test. Trial sequential analysis was used to reduce the risk of type I error and estimate whether the evidence of the results was sufficient.
  
  
  RESULTS
  Overall, a significant increased risk of prostate cancer was associated with MnSOD Val16Ala polymorphism for the heterozygote model (OR = 1.14; 95% CI, 1.05-1.24), homozygote model (OR = 1.18; 95% CI, 1.02-1.36), dominant model (OR = 1.24; 95% CI, 1.07-1.44) and recessive model (OR = 1.10; 95% CI, 0.96-1.24). In the subgroup analysis by genotyping method, the results were statistically significant for the TaqMan and PCR-RFLP methods. In addition, when stratified by sample size, statistically significant increased risks were found among both large samples and small samples. Furthermore, when stratified by source of control, significant results were detected in both population-based controls and hospital-based controls. By trial sequential analyses, these findings in the current study were shown to be based on sufficient evidence.
  
  
  CONCLUSIONS
  This meta-analysis indicated that the Ala allele of the MnSOD gene polymorphism increases prostate cancer susceptibility.
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation:  The First Clinical Medical College of Nanjing Medical University, Nanjing - PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Shen
authors.affiliation:  Department of Urology, Affiliated Cancer Hospital of Jiangsu Province of Nanjing Medical University, Nanjing - PR China.
authors.forename: Hongzhou
authors.initials: H
authors.lastname: Cai
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Kang
authors.initials: K
authors.lastname: Liu
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Yiyang
authors.initials: Y
authors.lastname: Liu
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Zhengkai
authors.initials: Z
authors.lastname: Huang
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Liang
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Xiaheng
authors.initials: X
authors.lastname: Deng
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Ye
authors.affiliation:  Department of Urology, Affiliated Cancer Hospital of Jiangsu Province of Nanjing Medical University, Nanjing - PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zou
authors.affiliation:  Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing - PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
mesh_terms: D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000235:genetics*; D013482:Superoxide Dismutase / Q000235:genetics*
chemical_list: D013482:Superoxide Dismutase