title: The IL-17A G-197A and IL-17F 7488T/C polymorphisms are associated with increased risk of cancer in Asians: a meta-analysis.
abstract: BACKGROUND
  Interleukin-17 (IL-17) is a family of emerged pro-inflammatory cytokines. The IL-17A and IL-17F are two important members of IL-17 family. Previous studies have shown that the functional IL-17A G-197A and IL-17F 7488T/C polymorphisms may contribute to susceptibility to cancer but the results were inconclusive. This meta-analysis was performed to determine the exact association between IL-17 polymorphisms and cancer risk.
  
  
  METHODS
  Online databases were searched to identify eligible case-control studies. Pooled odds ratios (ORs) and confidence intervals (CIs) were calculated by fixed-effect models or random-effect models. Publication bias was detected by Egger's test and Begg's test.
  
  
  RESULTS
  Nine eligible case-control studies of IL-17A G-197A and seven studies of IL-17F 7488T/C, including 3,181 cases and 4,005 controls, were identified. Pooled analysis suggested the variant IL-17A-197A allele was associated with increased risk cancer (GA/AA vs GG, OR =1.27, 95% CI: 1.15, 1.41, P heterogeneity =0.374; and A vs G, OR =1.30, 95% CI: 1.17, 1.45, P heterogeneity =0.021). For IL-17F 7488T/C, the homozygote 7488CC genotype significantly increased risk of cancer (CC vs TC/TT, OR =1.36, 95% CI: 0.97, 1.91, P heterogeneity =0.875; and CC vs TT, OR =1.39, 95% CI: 1.03, 1.88, P heterogeneity =0.979), especially for gastric cancer.
  
  
  CONCLUSIONS
  The variant IL-17A-197A allele and IL-17F 7488CC genotype were associated with increased risk of cancer, especially for gastric cancer.
authors.affiliation: Department of Gastroenterology, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, People's Republic of China.
authors.forename: Huifen
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, People's Republic of China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Center for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing, People's Republic of China.
authors.forename: Zhaolan
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Institute of Basic Research in Clinical Medicine, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China.
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, People's Republic of China.
authors.forename: Hongchuan
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Gastroenterology, China-Japan Friendship Hospital, Beijing University of Chinese Medicine, Beijing, People's Republic of China.
authors.forename: Shiyu
authors.initials: S
authors.lastname: Du
mesh_terms: D001208:Asia / Q000453:epidemiology; D044466:Asian People / Q000235:genetics*; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D020381:Interleukin-17 / Q000235:genetics*; D009369:Neoplasms / Q000175:diagnosis / Q000208:ethnology / Q000235:genetics* / Q000276:immunology; D016017:Odds Ratio; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D018570:Risk Assessment; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000208:ethnology / Q000235:genetics / Q000276:immunology
chemical_list: C508717:IL17A protein, human; C440021:IL17F protein, human; D020381:Interleukin-17
keywords: gastric cancer; gene polymorphism; interleukin-17; meta-analysis; risk