title: [Associations between genetic polymorphisms of glutathione S-transferase M1 and T1, smoking and susceptibility to colorectal cancer: a case-control study].
abstract: OBJECTIVE
  To evaluate the associations between genetic polymorphisms of glutathione S-transferase M1 and T1 (GSTM1 and GSTT1), smoking and susceptibility to colorectal cancer.
  
  
  METHODS
  A case-control study of 126 patients and 343 healthy controls was conducted to investigate the role of GSTM1 and GSTT1 polymorphisms in colorectal cancer. Genotypes of GSTM1 and GSTT1 polymorphisms were analyzed by multiplex allele-specific polymerase chain reaction (PCR).
  
  
  RESULTS
  The frequencies of GSTM1 null and GSTT1 null genotypes were 55.5% and 20.4%, respectively. After adjustment for age and sex, among those with GSTT1 null genotype, the GSTM1 null genotype had a significant increased risk of rectal cancers compared to GSTM1 non-null genotype (OR=9.74, 95% CI, 1.13 - 83.85). A 2.22-fold risk of colon cancers was associated with GSTM1 null genotype compared to GSTM1 non-null genotype among current smokers (P >0.05). Individuals with GSTT1 null genotype and currently smoking had a significant risk of colon cancers (OR = 4.55, 95% CI, 1.14 - 18.17), and rectal cancers (OR = 4.60, 95% CI, 1.11 - 19.11).
  
  
  CONCLUSIONS
  This study suggests that certain null GSTM1 and GSTT1 genotypes may be associated with an elevated risk of colorectal cancer which may be modified by interaction of the two genetic polymorphisms and cigarette smoking.
authors.affiliation: Department of Epidemiology and Statistics, School of Medicine, Zhejiang University, Hangzhou 310031, China. E-mail: CK@zjuem.zju.edu.cn
authors.forename: Kun
authors.initials: K
authors.lastname: Chen
authors.forename: Qin-ting
authors.initials: QT
authors.lastname: Jiang
authors.forename: Xin-yuan
authors.initials: XY
authors.lastname: Ma
authors.forename: Kai-yan
authors.initials: KY
authors.lastname: Yao
authors.forename: Shu-guang
authors.initials: SG
authors.lastname: Leng
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Yu
authors.forename: Hai-guang
authors.initials: HG
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000201:enzymology / Q000235:genetics*; D005260:Female; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012004:Rectal Neoplasms / Q000201:enzymology / Q000235:genetics*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1