title: Association of heme oxygenase-1 polymorphisms with cancer risk: A systematic review and meta-analysis.
abstract: OBJECTIVE
  Observational studies have recently focused on the association between heme oxygenase-1 (HMOX1) gene promoter polymorphisms and cancer risk. However, conflicting results have been obtained. To derive a precise estimate of the association, a systematic review and meta-analysis were conducted.
  
  
  METHODS
  This study followed the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Medline, Embase and Web of Knowledge were systematically searched for relevant studies. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the allelic and genotypic comparisons according to the homozygous, heterozygous, dominant, and recessive genetic models. Between-study heterogeneity was quantified through I2 statistics, and publication bias was appraised by using funnel plots. Sensitivity analyses were conducted to evaluate the robustness of the meta-analysis findings.
  
  
  RESULTS
  Meta-analysis of 9 studies involving 2491 cases and 3380 controls did not reveal any significant association of the HMOX-1 (GT)n and 413A>T polymorphisms with cancer risk. Stratified analysis by ethnicity showed a statistically significant association between (GT)n repeat length variant and susceptibility to cancer for the heterozygous genetic model among Asian populations (OR=1.42, 95% CI: 1.04-1.95, Pheterogeneity=0.218), which is a robust finding according to sensitivity analysis. Funnel plot inspection did not reveal any publication bias.
  
  
  CONCLUSIONS
  In conclusion, this study comprehensively examined the available literature on the association of HMOX-1 (GT)n and 413A>T polymorphisms with cancer risk. Meta-analysis results suggest (GT)n repeat length polymorphism as a potential susceptibility variant for cancer in Asians. Additional large-scale and well-designed studies are needed to confirm these results.
authors.affiliation: Oncology Center, the Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001, China.
authors.forename: Haiqing
authors.initials: H
authors.lastname: Luo
authors.forename: Yiming
authors.initials: Y
authors.lastname: Shao
authors.forename: Na
authors.initials: N
authors.lastname: Yao
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Chen
authors.forename: Liren
authors.initials: L
authors.lastname: Hu
authors.forename: Taiping
authors.initials: T
authors.lastname: He
mesh_terms: D020022:Genetic Predisposition to Disease; D051547:Heme Oxygenase-1 / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000209:etiology / Q000235:genetics*; D011110:Polymorphism, Genetic; D017594:Publication Bias; D012091:Repetitive Sequences, Nucleic Acid; D012306:Risk
chemical_list: D051547:Heme Oxygenase-1