title: Genetic susceptibility and environmental factors of esophageal cancer in Xi'an.
abstract: OBJECTIVE
  To analyse the role of genetic susceptibility and environmental factors in the process of esophageal cancer (EC) formation in Xi'an, China.
  
  
  METHODS
  A hospital based case-control study, combined with molecular epidemiological method, was carried out. A total of 127 EC cases and 101 controls were interviewed with questionnaires containing demographic items, habit of tobacco smoking, alcohol drinking, and family history of EC. Polymorphism of CYP1A1 and GSTM1 of 127 EC cases and 101 controls were detected by PCR method. The interactions between genetic susceptibility and environmental factors were also discussed.
  
  
  RESULTS
  Tobacco smoking, alcohol drinking and a family history of EC were risk factors for EC with an OR of 2.04(95% CI 1.15-3.60), 3.45(95% CI 1.74-6.91), 3.14 (95% CI 1.28-7.94), respectively. Individuals carrying CYP1A1 Val/Val genotype compared to those with CYP1A1 Ile/Ile genotype had an increased risk for EC (OR 3.35, 95% CI 1.49-7.61). GSTM1 deletion genotype was a risk factor for EC (OR1.81, 95% CI 1.03-3.18). Gene-environment interaction analysis showed that CYP1A1 Val/Val genotype, GSTM1 deletion genotype had synergetic interactions with tobacco smoking, alcohol drinking and family history of EC.
  
  
  CONCLUSIONS
  Tobacco smoking, alcohol drinking and a family history of EC are risk factors for EC. CYP1A1 Val/Val and GSTM1 deletion genotypes are genetic susceptibility biomarkers for EC. There are synergic interactions between genetic susceptibility and environmental factors.
authors.affiliation: Department of Epidemiology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an 710033, Shanxi Province, China. wanganhui@hotmail.com
authors.forename: An-Hui
authors.initials: AH
authors.lastname: Wang
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Sun
authors.forename: Liang-Shou
authors.initials: LS
authors.lastname: Li
authors.forename: Jiu-Yi
authors.initials: JY
authors.lastname: Huang
authors.forename: Qing-Shu
authors.initials: QS
authors.lastname: Chen
authors.forename: De-Zhong
authors.initials: DZ
authors.lastname: Xu
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects; D002274:Carcinogens, Environmental / Q000009:adverse effects*; D016022:Case-Control Studies; D002681:China; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000209:etiology* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008297:Male; D012907:Smoking / Q000009:adverse effects
chemical_list: D002274:Carcinogens, Environmental; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase