AML with t(8;21)(q22;q22), (AML1/ETO)

Acute myelogenous leukemia (AML) with t(8;21)(q22;q22) is an acute myelogenous leukemia generally showing maturation in the neutrophil lineage. The protein encoded by this gene is a putative zinc finger transcription factor and oncoprotein. In acute myeloid leukemia, especially in the M2 subtype, the t(8;21)(q22;q22) translocation is one of the most frequent karyotypic abnormalities. The translocation produces a chimeric gene made up of the 5'-region of the RUNX1 gene fused to the 3'-region of this gene. The chimeric protein is thought to associate with the nuclear corepressor/histone deacetylase complex to block hematopoietic differentiation. Several transcript variants encoding multiple isoforms have been found for this gene.^[1]

Sample Cases

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Case Name (click on case name to open)	Comments	Size
case 18	AML M2 with t(8:21). This case was kindly provided by the ASCP Press. It is part of Flow Cytometry in Clinical Diagnosis by John Carey, Phil McCoy and David Keren.	829.9 kB

Epidemiology

Acute myelogenous leukemia (AML) with t(8;21)(q22;q22) is one of the most common structural aberrations in AML and can be found in 5-12% of cases of AML and in one third of karyotypically abnormal cases of AML with maturation. It occurs predominantly in younger patients.

Possible causes

Morphology

AML with t(8;21)(q22;q22) most often display the morphology of acute myeloid leukemia (AML-M2). Blasts are generally large with variable numbers of azurophillic granules and Auer rods.

Immunophenotyping

These cases are phenotypically positive for pan-myeloid markers (CD13, CD33) and blast markers (CD34 and CD117), and characteristically for CD19 and CD56. Occasionally cases may show lack of surface pan-myeloid antigens. Besides the frequent coexpression of CD19/CD56, AML with t(8;21) demonstrates a higher incidence of CD34, TdT and lower levels of CD13/CD33 expression.

Other relevant tests

Cytochemistry

Genetics

Sub-classification

Flow Diagnosis

References

Ferrara F, Del Vecchio L (2002). "Acute myeloid leukemia with t(8;21)/AML1/ETO: a distinct biological and clinical entity.".Haematologica 87 (3): 306-19. PMID 11869944.
Erickson PF, Dessev G, Lasher RS, et al. (1996). "ETO and AML1 phosphoproteins are expressed in CD34+ hematopoietic progenitors: implications for t(8;21) leukemogenesis and monitoring residual disease.". Blood 88 (5): 1813-23. PMID 8781439.