ABSTRACT
NAD [p] H: quinone oxidoreductase NQO1 originally called DT-diaphorase is an enzyme that is able to detoxify a number of natural and synthetic compounds, including quinones and their derivatives. It is induced by synthetic antioxidants and cruciferous vegetables and protects cells against oxidative stress. The human NQO1gene is located on chromosome 16q22.1, a single nucleotide polymorphism [cytosine to thymine, [CT]] at position 609 in the NQO1 gene has been identified in a human colon cancer cell line with very low NQO1 activity. This variant produces a proline-to-serine substitution that inactivates the enzyme. People who are homozygous for the variant allele completely lack NQO1 activity, while heterozygote have low to intermediate activity compared with people with the wild type. The incidence of the polymorphism varies widely by race, and associations have been made between the presence of variant alleles and lung and urological cancers. NQO1 mutation had been identified as risk factor in AML and ALL but no avilable data in chronic myeloid leukemia. Our study included 21 chronic myeloid patients and 10 apparently healthy persons using PCR-RFLP technique to detect the NQO1 nutation. Among the cases 11[52.4%] were positive for the mutation compared to 1[10%] of control. A higher incidence of the mutation was noticed among patients in crisis stage. Conclusion from our data we noticed a high incidence of NQO1 mutation in cases of CML which may suggest an important role of this gene in the etiology and pathogenesis of chronic myeloid leukemia