title: Effect of the polymorphisms of tumor necrosis factor-α gene on the susceptibility to primary biliary cirrhosis:  a meta-analysis.
abstract: BACKGROUND
  Previous studies have shown the genetic association of tumor necrosis factor (TNF)-α polymorphisms and susceptibility to primary biliary cirrhosis (PBC), but the results of individual studies have remained contradictory. Therefore, a meta-analysis was carried out to evaluate comprehensively the association of TNF-α polymorphisms and susceptibility to PBC.
  
  
  METHODS
  The relevant published articles were searched in PubMed, EMBASE, and Cochrane library. Data were extracted using standardized forms and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for each study. Pooled data were estimated by fixed-effects and random-effects models when appropriate. We analyzed the association between the 'A' allele at position -308(rs1800629) and -238(rs361525) and the risk of PBC.
  
  
  RESULTS
  We examined eight publications, showing that all eight studies discussed the TNF-α -308(rs1800629) polymorphism; four studies were relevant with -238(rs361525). No significant associations were found between the 'A' allele frequency of rs1800629 and rs361525 and the risk of PBC in the overall population (OR=0.89, 95% CI 0.71-1.11, P=0.91; OR=0.98, 95% CI 0.66-1.47, P=0.93) and in Whites (OR=0.94, 95% CI 0.74-1.19, P=0.58; OR=1.01, 95% CI 0.64-1.59, P=0.97). Besides, it was also found that the genotype (AA+AG vs. GG, GG+AG vs. AA) was not linked to susceptibility to PBC.
  
  
  CONCLUSIONS
  The meta-analysis indicated that none of these two polymorphisms (-308G/A and -238G/A) showed any significant association with the risk of PBC.
authors.affiliation: Department of Laboratory Diagnostics, Changzheng Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Baodong
authors.initials: B
authors.lastname: Qin
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.forename: Zaixing
authors.initials: Z
authors.lastname: Yang
authors.forename: Renqian
authors.initials: R
authors.lastname: Zhong
mesh_terms: D016009:Chi-Square Distribution; D005006:Ethnicity / Q000235:genetics; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000208:ethnology / Q000235:genetics* / Q000276:immunology; D016017:Odds Ratio; D010641:Phenotype; D011110:Polymorphism, Genetic; D018570:Risk Assessment; D012307:Risk Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha