Background: Myeloid malignancles carrylng t(8;21)(q22;q22) exhibit several characteristic features. This translocation is most often associated with acute myeloid leukemia with maturation(AML-M2), but rarely wlth myelodysplastic syndrome. We studied the correlation of cytogenetics, morphology, and immunophenotype in 21 myelold malignancies carrying t(8;21).
Methods: We analyzed 21 t(8;21) positive myeloid malignancies for morphology, immunophsnotype and cytogenetics, retrospectively. Ws also peformed reverse
transcription polymerase chain reaction(RT-PCR) for AML1-ETO fusion transcripts using marrow sildes stored at room temperature.
Results: 17 patients were diagnosed as French-American-British(FAB) types M2 and 4 cases as refractory anemia with excess blasts in transformation(RAEB-t). Three patients had marrow eosinophilia and 14 cases(67%) had Auer rods in leukemic blasts.
Three patients(14%) developed granulocylic sarcomas. Four patients had variant t(8;21) translocation and 16(76%) had secondary clonal abnormalities, most commonly loss of a
sex chromosome(52%). 15 patients(83%) aberrantly expressed CDl9. AML1 -ETO fusion transcript of same size was observed in classic and variant t(8;21) translocation(11/14, 79%).
Conclusion: Our study showed that myeloid malignancles carrying t(8;21) have distinctive morphological, immunophenotypical, and molecular features. These results can be aid to understand the pathogenesis and stratify treatment of those malignancies in the future.

Keywords: Myeloid malignancies, t(8,21), AML1-ETO, CD19