 The malignant cell in AML is the myeloblast . In normal <unk> , the myeloblast is an immature precursor of myeloid white blood cells ; a normal myeloblast will gradually mature into a mature white blood cell . In AML , though , a single myeloblast <unk> genetic changes which " freeze " the cell in its immature state and prevent differentiation . Such a <unk> alone does not cause leukemia ; however , when such a " differentiation arrest " is combined with other mutations which disrupt genes controlling proliferation , the result is the uncontrolled growth of an immature clone of cells , leading to the clinical entity of AML . 
