Contrary to the majority of the aforementioned studies, which found that CYP2D6*4 IM polymorphism incidence was higher in CML (mostly Ph+ve) patients when compared with controls, our results showed a protective property of (IM) allele against Ph-ve CML as it was considerably higher in controls than Ph-ve CML. The gene discussed is CYP2D6; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.