title: Thymidylate synthase genetic polymorphisms and cancer risk: a meta-analysis of 37 case-control studies.
abstract: BACKGROUND
  Several studies have evaluated the association between polymorphisms of thymidylate synthase (TS) and cancer risk in diverse populations but with conflicting results. By pooling the relatively small samples in each study, it is possible to evaluate the association using a meta-analysis.
  
  
  METHODS
  A comprehensive search was conducted to identify all case-control studies on TS on a 28-bp tandem repeats in 5'untranslated region (5'UTR) and a 6-bp insertion (ins) and deletion (del) mutation in 3'UTR of the gene and cancer risk. Meta-analysis was conducted using a fixed and random effect model.
  
  
  RESULTS
  Our meta-analysis on a total of 13 307 cancer cases and 18 226 control subjects from 37 published case-control studies showed no significant association between the risk of cancer and the 5'UTR 28-bp tandem repeats polymorphism (3R/3R vs. 2R/2R: OR = 1.06, 95%CI, 0.93 - 1.20) or the 3'UTR 6-bp ins/del polymorphism (del6/del6 vs. ins6/ins6: OR = 0.93, 95%CI, 0.81 - 1.08) with significant between-study heterogeneity. In the cancer type- and ethnic subgroup-stratification analyses, we did not find any association between TS polymorphisms and cancer risk either.
  
  
  CONCLUSIONS
  TS 5'UTR 28-bp tandem repeats and 3'UTR 6-bp ins/del polymorphisms may not be associated with cancer risk.
authors.affiliation: Department of Digestive System, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Tang
authors.forename: Pei-Pei
authors.initials: PP
authors.lastname: Wang
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Zhuang
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Chen
authors.forename: Feng-Ting
authors.initials: FT
authors.lastname: Huang
authors.forename: Shi-Neng
authors.initials: SN
authors.lastname: Zhang
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D020080:Tandem Repeat Sequences / Q000235:genetics; D013940:Thymidylate Synthase / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D013940:Thymidylate Synthase