Study of a 96-bp insertion polymorphism in the regulatory region of CYP2E1 in cancer patients in comparison with healthy populations in kashan

Cytochrome P450 2E1 (CYP2E1) is involved in the metabolic activation of a wide variety of potential carcinogens, and functional polymorphisms in the CYP2E1 gene have been investigated in relation to various cancers. We examined the relation of the CYP2E1 96-bp insertion polymorphism to cancer risk and the interaction between this polymorphism and some lifestyle risk factors. This study was conducted on 101 samples of patients suffering from four types of lung, breast, stomach and colorectal cancer and 131 healthy individuals as a control group. After extracting DNA from blood samples, the genotype of CYP2E1 96-bp insertion polymorphism was done by molecular PCR method. We found the frequency of the CYP2E1 96-bp insertion to be 66.3 % (67/101) for non-insertion (i/i), 14.9 % (15/101) for heterozygous insertion (i/I) and 18.8 % (19/101) for homozygous insertion (I/I) among case group. The genotypes with allele I (II/Ii) in the CYP2E1 locus have a significant difference in both patient and healthy groups (p value: 0.011). We also found a positive association between smoking and cancer risk (p value:0/004). In this study, the allelic frequencies in normal group were 0.16.4 for I and 0.85.6 for i allele. To conclude, this work is the first study on the genotype distribution of CYP2E1 96-bp insertion polymorphism in Iranian population. The molecular studies on this enzyme provide basis for further epidemiological investigations in populations where the functional mutations in the genes alter therapeutic response and as susceptibility markers for various clinical conditions as well as lifestyle risk factors for cancer.