CYP1A1, GSTM1 and GSTT1 Genetic Polymorphism in Egyptian Chronic Myeloid Leukemia Patients

The genetic polymorphism of xenobiotic metabolizing enzymes: phase I enzymes; cytochrome P450 (CYP1A1) and phase II enzymes; glutathione S-transferase (GSTM1 and GSTT1), were analyzed in 30 chronic myeloid leukemia patients (CML) (19 females, 11 males; age (Mean±SD) 41.7±9.5 years) and 20 age and sex matched healthy controls. The frequency of CYP1A1 alleles and of GSTT1 and GSTM1 homozygous deletions was examined by PCR- RFLP and PCR methods, respectively, using blood samples. The relationship between these genotypes and risk of CML was assessed by means of Odds Ratio (OR) with 95% confidence limits. Present results showed that the frequency of the mutant allele CYP1A1*2A was found to be 3.3% in CML patients and 45% in controls (OR = 0.042, 95% CI: 0.005-0.373; p<0.001), suggesting that this polymorphic variant may be a protective factor against CML. The frequency of individuals carrying the GSTT1 null genotype was higher among CML patients (60%) compared to controls (15%) (OR = 8.5, 95% CI: 2.038-35.458; p = 0.002). Therefore, GSTT1 null genotype may be a risk factor for CML. Although, GSTM1 null genotype frequency was slightly higher in the patient group (46.7%) than in the controls (40%), this difference was not statistically significant (OR = 1.313, 95% CI: 0.417-4.131; p = 0.642). In conclusion this data suggests that polymorphic CYP1A1 and GSTT1 genes appear to affect susceptibility to CML.