title: Associations between the four toll-like receptor polymorphisms and the risk of gastric cancer: a meta-analysis.
abstract: OBJECTIVE
  The association between Toll-like receptor 2 (TLR2) -196 to -174del polymorphism and Toll-like receptor 4 (TLR4) polymorphisms (Asp299Gly, Thr399Ile, and 3725G>C) and gastric cancer risk are still conflicting. For better understanding of the effects of these four polymorphisms on gastric cancer risk, a meta-analysis was performed.
  
  
  METHODS
  An extensive search was performed to identify all case-control studies investigating such associations. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the relationship.
  
  
  RESULTS
  A total of 21 studies (3,436 cases and 4,239 controls) were found to be eligible for meta-analysis. In the overall analysis, a significantly increased risk was observed in TLR4 Asp299Gly polymorphism (G allele vs. A allele: OR=1.84, 95%CI: 1.41, 2.39; GA vs. AA: OR=1.89, 95%CI: 1.43, 2.48; Recessive model: OR=1.90, 95%CI: 1.44, 2.49) and TLR4 Thr399Ile polymorphism (T allele vs. C allele: OR=1.97, 95%CI: 1.22, 3.18; TC vs. CC: OR=1.94, 95%CI: 1.19, 3.15; Recessive model: OR=1.98, 95%CI: 1.21, 3.21), whereas no associations were found in any genetic models of TLR2 -196 to -174del and TLR4 3725G>C polymorphisms. Similar results were found in the subgroup analyses by ethnicity. However, we detected that A allele carriers of the TLR4 Asp299Gly polymorphism might have an increase risk of gastric cancer in the Helicobacter pylori-positive population (G allele vs. A allele: OR=2.01, 95%CI: 1.22, 3.31).
  
  
  CONCLUSIONS
  The results of this meta-analysis indicate that the TLR4 Asp299Gly and Thr399Ile polymorphisms are risk factors for gastric cancer development.
authors.affiliation: 1 Institute of Genetic Engineering, Southern Medical University , Guangzhou, China .
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Sheng
authors.initials: S
authors.lastname: Hu
authors.forename: Sanghua
authors.initials: S
authors.lastname: Liang
authors.forename: Qilong
authors.initials: Q
authors.lastname: Chen
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Yang
authors.forename: Wenling
authors.initials: W
authors.lastname: Zheng
authors.forename: Wenli
authors.initials: W
authors.lastname: Ma
mesh_terms: D000483:Alleles; D044466:Asian People; D016022:Case-Control Studies; D005808:Genes, Recessive; D020022:Genetic Predisposition to Disease; D005838:Genotype; D016480:Helicobacter pylori / Q000378:metabolism; D006579:Heterozygote; D006801:Humans; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012306:Risk; D013274:Stomach Neoplasms / Q000208:ethnology / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000235:genetics*; D044465:White People
chemical_list: C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4