Background and purpose: Gastric cancer is the most common malignant tumor and the leading cause of death in Qinghai province. The possible chemical procarcinogens in our living environment must be activated and transformed ultimately into carcinogens by CYP2E1 of cytochrome

one of the most important Ⅰ phase metabolic enzymes in hu

man body

and also the genetic polymorphisms of CYP2E1 are reportedly in different ethnic groups and in different regions. The aim of this study was to investigate the correlation between genetic polymorphisms of CYP2E1 DraⅠ and the susceptibility of gastric cancer in Qinghai province. Methods: A case control study was performed with the molecular epidemiological methods. A total of 120 gastric cancer cases (as the gastric cancer group) and 120 healthy people (as the control group) were randomly selected from affiliated hospital of Qinghai University from Jan. 2010 to Apr. 2012

and all of the individuals were living in Qinghai province. The genotypes and alleles of CYP2E1 DraⅠ in both of the above groups were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)

and then the outcome was analyzed statistically. Results: The distribution frequency of CYP2E1 DraⅠ genotypes (including C/C

C/D

D/D) was 58.33%

35.00% and 6.67% in the patient group respectively

58.33%

38.34% and 3.33% in the control group respectively

which showed no significant differences between the two groups (the value of P were 1.00

0.59 and 0.24

respectively). The distribution frequency of CYP2E1 DraⅠ alleles (including C and D) was 75.83% and 24.17% in the patient group respectively

meanwhile

77.50% and 22.50% in the control group respectively

which also showed no significant difference between the two groups (χ

2

=0.19

P=0.67). Interestingly

the mutant genotypes (C/D

D/D) of CYP2E1 DraⅠ were associated with the well and well-moderately differentiated gastric adenocarcinoma in a way (χ

2

=4.49 and P=0.03; OR=3.5 and 95%CI: 1.04-11.80)

and it was also demonstrated that the mutant genotypes (C/D

D/D) were the risk factors for the oncogenesis of well and wellmoderately differentiated gastric adenocarcinoma; The wild homozygote (C/C) of CYP2E1 DraⅠ was related to poorly differentiated gastric adenocarcinoma (χ

2

=3.97 and P=0.049; OR=0.54 and 95%CI: 0.29-1.00 )

and it

was still revealed that the wild homozygote (C/C) of CYP2E1 DraⅠ was the risk factor for the tumorigenesis of poorly differentiated gastric adenocarcinoma. Conclusion: The genetic polymorphisms of CYP2E1 DraⅠ are to some extent associated with the susceptibility of different differentiated gastric adenocarcinoma in Qinghai province

furthermore

carriers of wild homozygote (C/C) of CYP2E1 DraⅠ are relatively prone to the risk factor to the occurrence of poorly differentiated gastric adenocarcinoma

and carriers of mutant homozygote (D/D) and mutant heterozygote (C/D) are also liable to occur the well/well-moderated differentiated gastric adenocarcinoma in Qinghai province.