Background: The human AML1 gene, located on chromosome 21, can be fused to the AML1- eight-twenty-one (ETO) oncoprotein on chromosome eight, resulting in a t(8;21)(q22;q22) translocation. Acute myeloid leukemia (AML) associated with this translocation is considered a distinct AML with a favorable prognosis. Due to the various incidences of the translocation, which is associated with geographic diversities, investigation of molecular epidemiology is important to increase the awareness of physicians and hematologists regarding the frequency this chromosomal aberration.

Methods: The patients were classified according to the French–American–British classification into eight groups: M0–M7. Determination of the prevalence of the AML1-ETO fusion gene was accomplished by TaqMan real-time PCR. Bone marrow samples from 113 patients with newly-diagnosed, untreated AML -M1, -M2, and -M4, and 20 healthy controls admitted to the Ghaem Hospital in Mashhad, Iran were studied.

Results: The AML1-ETO fusion gene was detected up 50% of the M2 subgroup and absent in the M1 and M4 subtypes and healthy controls. Comparison of the prevalence of the t(8;21) translocation with results of previous studies showed that it varies between countries. This result may be due to geographic or ethnic differences, or both.

Conclusions: The relatively high prevalence of the t(8;21) translocation in Iran was similar to that found in other Asian countries. It was closely associated with female gender, relatively young age, and FAB-M2 subtype. Its distribution varied considerably with geographic area. Therefore, further studies are needed to provide epidemiological data important for the establishment of optimal therapeutic strategies applicable to patients of each region.