title: [Interactions between lifestyle, methylanetetrahydrofolate reductase gene and polymorphisms in thymidylate synthase gene with risk of stomach cancer].
abstract: OBJECTIVE
  To evaluate interactions between lifestyle, methylanetetrahydrofolate reductase gene (MTHFR) and polymorphisms in the 3'-untranslated region (3'-UTR) of the thymidylate synthase gene (TS) with reference to development of stomach cancer (SC).
  
  
  METHODS
  We conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. TS genotypes were identified by polymerase chain reaction.
  
  
  RESULTS
  (1) The frequencies of TS genotypes (+6 bp/+6 bp, +6 bp/-6 bp and -6 bp/-6 bp) among the cases were 5.6%, 47.7% and 46.7% and among the controls were 9.0%, 54.0% and 37.0%, respectively. Individuals identified as -6 bp/-6 bp genotype had a slightly higher risk for SC than those individuals with +6 bp alleles (the crude OR = 1.49, 95% CI: 0.90 - 2.47; adjusted OR = 1.36, 95% CI: 1.00 - 1.78, P = 0.047). (2) Individuals having TS -6 bp/-6 bp genotype and having smoking habit were at a significantly higher risk of developing SC (adjusted OR = 2.79, 95% CI: 1.51 - 5.18) compared with those who had +6 bp alleles with no smoking habit. Individuals having TS -6 bp/-6 bp genotype and habit of frequent alcohol drinking were at an increased risk of developing SC (adjusted OR = 1.76, 95% CI: 1.07 - 2.90) compared with those with +6 bp alleles and low consumption of alcohol. As compared with individuals with +6 bp alleles and who had habit of tea drinking, individuals who had TS -6 bp/-6 bp genotype and but without habit of tea drinking had an increased risk of developing SC (adjusted OR = 2.34, 95% CI: 1.43 - 3.82). (3) Individuals with TS -6 bp/-6 bp genotype and with MTHFR T alleles had an increased risk of developing SC (adjusted OR = 2.67, 95% CI: 1.07 - 6.70) compared with those with +6 bp alleles and with MTHRF C/C genotype.
  
  
  CONCLUSIONS
  Results in the present study suggested that there was a combined effect between lifestyle, MTHFR C/T or T/T genotype and TS -6 bp/-6 bp genotype in the development of SC.
authors.affiliation: Department of Epidemiology, Jiangsu Province Institute of Cancer Research, Nanjing 210009, China.
authors.forename: Chang-ming
authors.initials: CM
authors.lastname: Gao
authors.forename: Jian-zhong
authors.initials: JZ
authors.lastname: Wu
authors.forename: Yan-ting
authors.initials: YT
authors.lastname: Liu
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Ding
authors.forename: Su-ping
authors.initials: SP
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Su
authors.forename: Xu
authors.initials: X
authors.lastname: Hu
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Kai
authors.forename: Takezaki
authors.initials: T
authors.lastname: Toshiro
authors.forename: Tajima
authors.initials: T
authors.lastname: Kazuo
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008019:Life Style; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D017354:Point Mutation; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000235:genetics; D013662:Tea / Q000737:chemistry; D013940:Thymidylate Synthase / Q000235:genetics*
chemical_list: D013662:Tea; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D013940:Thymidylate Synthase