title: Tumor necrosis factor-a polymorphisms and colorectal cancer risk: a meta-analysis.
abstract: OBJECTIVE
  Tumor necrosis factor-alpha (TNF-a) was related to inflammation and involved in the development of colorectal cancer. Polymorphisms located in TNF-a promoter region, such as 308G/A and 238G/A, could affect the risk of various types of cancer by regulating TNF-a production. In this study, a meta-analysis was performed to investigate the association between common polymorphisms of TNF-a promoter region and colorectal cancer susceptibility.
  
  
  METHODS
  Searching of several databases was performed for all publications on the association between TNF-a polymorphisms and colorectal cancer. Summary odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated using random-effects models. Stratified analyses based on ethnicity and control population source were also conducted.
  
  
  RESULTS
  Overall, TNF-a 308A polymorphism showed a significant association with increased risk of colorectal cancer in worldwide populations under homozygote comparison [AA vs. GG, OR (95% CI) = 1.46 (1.07-1.97)] other than heterozygote comparison [AG vs. GG, OR (95% CI) = 1.05 (0.93-1.19)]. TNF-a 238A was not associated with colorectal cancer risk under homozygote or heterozygote comparisons. In stratified analysis, significant association was observed only in Western populations [AA vs. GG, OR (95% CI) = 1.39 (1.01-1.91)] other than in Eastern populations under homozygote comparison. No significant difference was observed between population-based subgroup and hospital-based subgroup.
  
  
  CONCLUSIONS
  TNF-a 308A was moderately associated with an increased risk of colorectal cancer in Western populations, and TNF-a 238A polymorphism was not significantly associated with colorectal cancer risk.
authors.affiliation: Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Departments of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Min
authors.affiliation: Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Departments of Epidemiology, Peking University Cancer Hospital & Institute, Beijing, China.
authors.forename: Duo
authors.initials: D
authors.lastname: Chen
authors.affiliation: Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Departments of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing, China.
authors.forename: Like
authors.initials: L
authors.lastname: Qu
authors.affiliation: Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Departments of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing, China.
authors.forename: Chengchao
authors.initials: C
authors.lastname: Shou
mesh_terms: D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D017594:Publication Bias; D012306:Risk; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha