Co-existence of AML1-ETO and BCR-ABL1 transcripts in a relapsed patient of acute myeloid leukemia with favorable risk group: A coincidence or clonal evolution?

Prognosis of acute myeloid leukemia relies heavily on the cytogenetic and molecular abnormalities. AML1-ETO fusion protein resulting from t(8;21), a recurring cytogenetic abnormality, is known to be associated with favorable prognosis. Additional molecular defects may, however, co-operate with the fusion proteins and alter the course of the disease. Among the additional cytogenetic defects, presence of Philadelphia (Ph) chromosome has rarely been documented in this subtype. Little is known about the consequences of its interactions with AML1-ETO, and its effect on morphological and clinical picture. Moreover, Ph+ clones or subclones may appear at any point during the disease course. We herein report one such unusual case of a 26-year-old female, who was diagnosed to have t(8;21) and managed accordingly. During disease relapse after 2.5years, the bone marrow showed extensive eosinophilia and basophilia. Subsequent molecular testing showed the presence of BCR-ABL in addition to the AML1-ETO fusion product.