title: Case-only study of interactions between metabolic enzymes and smoking in colorectal cancer.
abstract: BACKGROUND
  Gene-gene and gene-environment interactions involved in the metabolism of carcinogens may increase the risk of cancer. Our objective was to measure the interactions between common polymorphisms of P450 (CYP1A2, CYP1B1, CYP2E1), GSTM1 and T1, SULT1A1 and cigarette smoking in colorectal cancer (CRC).
  
  
  METHODS
  A case-only design was conducted in a Chinese population including 207 patients with sporadic CRC. Unconditional logistic regression analysis was performed adjusting for age, gender, alcohol consumption, and cigarette smoking.
  
  
  RESULTS
  The interaction odds ratio (COR) for the gene-gene interaction between CYP1B1 1294G and SULT1A1 638A allele was 2.68 (95% CI: 1.16-6.26). The results of the gene-environment analyses revealed that an interaction existed between cigarette smoking and the CYP1B1 1294G allele for CRC (COR = 2.62, 95%CI: 1.01-6.72), the COR for the interaction of CYP1B1 1294G and smoking history > 35 pack-years was 3.47 (95%CI: 1.12-10.80). No other significant gene-gene and gene-environment interactions were observed.
  
  
  CONCLUSIONS
  Our results showed that the interaction between polymorphisms in CYP1B1 1294G and SULT1A1*2 may play a significant role on CRC in the Chinese population. Also, it is suggested that the association between cigarette smoking and CRC could be differentiated by the CYP1B1 1294G allele.
authors.affiliation: Department of Epidemiology & Health Statistics, School of Public Health, Zhejiang University, Hangzhou, Zhejiang, China. happydou_8@hotmail.com <happydou_8@hotmail.com>
authors.forename: Chunhong
authors.initials: C
authors.lastname: Fan
authors.forename: Mingjuan
authors.initials: M
authors.lastname: Jin
authors.forename: Kun
authors.initials: K
authors.lastname: Chen
authors.forename: Yongjing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Zhang
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
mesh_terms: D017677:Age Distribution; D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000453:epidemiology / Q000235:genetics*; D016001:Confidence Intervals; D065633:Cytochrome P-450 CYP1B1; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D053858:Metabolic Networks and Pathways; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D011336:Probability; D011379:Prognosis; D012016:Reference Values; D018570:Risk Assessment; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology / Q000235:genetics*
chemical_list: D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D065633:Cytochrome P-450 CYP1B1