title: A meta-analysis: The association between interleukin-17 pathway gene polymorphism and gastrointestinal diseases.
abstract: BACKGROUND
  A number of studies have been conducted to investigate associations between genetic polymorphisms in interleukin-17 (IL-17) pathway and the risk of gastrointestinal diseases. Results, however, have been inconclusive. We aimed to evaluate these associations through a meta-analysis.
  
  
  METHODS
  We searched electronic databases (PubMed, Embase, Web of Science, CBM and CNKI) to identify papers, published before October 2014, on associations between polymorphisms in the IL-17 pathway genes (rs2275913, rs763780, rs3748067, rs3819025, rs9382084, rs12203582 and rs8193036) and the risk of gastrointestinal diseases. We estimated the strength of candidate associations through calculating pooled odds ratios (ORs) and 95% confidence intervals (CIs). A test of heterogeneity, a false-positive report probability (FPRP) test, sensitivity analyses and examination for bias were further conducted to evaluate cumulative evidence of these associations.
  
  
  RESULTS
  We identified 25 eligible case-control studies retrieved from 16 articles involved in a total of 4507 cases and 5733 controls. Of them, IL-17 (-197G/A) polymorphism (rs2275913) was statistically significantly associated with risk of gastrointestinal diseases, especially for gastrointestinal malignancy and gastroduodenal diseases. Based on heterogeneity (P<0.05) and FPRP (P<0.2) identified in this study, we graded cumulative epidemiological evidence of an association with gastrointestinal diseases for this polymorphism. However, IL-17 (7488T/C) polymorphism (rs763780) did not show significant associations with gastrointestinal diseases either individually or overall (P>0.05).
  
  
  CONCLUSIONS
  Our study provides moderate evidence that IL-17 (-197G/A) polymorphism may be a potential risk factor for gastrointestinal diseases, particularly for malignancy. Further validation of this association in a large homogeneous study is warranted.
authors.affiliation: Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yu-Xing
authors.initials: YX
authors.lastname: Jiang
authors.affiliation: Department of Health Statistics, Third Military Medical University, Chongqing, China.
authors.forename: Gao-Ming
authors.initials: GM
authors.lastname: Li
authors.affiliation: Department of Health Statistics, Third Military Medical University, Chongqing, China. Electronic address: yd_house@hotmail.com.
authors.forename: Dong
authors.initials: D
authors.lastname: Yi
authors.affiliation: Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China. Electronic address: yupeiwu01@vip.sina.com.
authors.forename: Pei-Wu
authors.initials: PW
authors.lastname: Yu
mesh_terms: D016206:Databases, Bibliographic; D005767:Gastrointestinal Diseases / Q000235:genetics* / Q000473:pathology; D056726:Genetic Association Studies / Q000379:methods*; D006801:Humans; D020381:Interleukin-17 / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: C508717:IL17A protein, human; C440021:IL17F protein, human; D020381:Interleukin-17
keywords: Carcinoma; Gastrointestinal diseases; Gene polymorphism; Interleukin-17; Meta-analysis