Clonal selection of CD56(+) t(8;21) AML blasts: further suggestion of the adverse clinical significance of this biological marker

Although patients with acute myelogenous leukaemia (AML) and t(8;21)(q22;q2 2) have a favourable prognosis, a subset die despite receiving appropriate treatment. Recent reports suggest that expression of the CD56 antigen might predict for both extramedullary disease and poor outcome in these patients . We describe a patient who presented with CD56-negative t(8;21) AML who ac hieved a complete remission and was subsequently treated with three consoli dative courses of high-dose cytarabine therapy. She relapsed 9 months later with extramedullary and bone marrow involvement of CD56-positive t(8;21) A ML. This case demonstrates clonal evolution and provides further support th at blast expression of CD56 might be an unfavourable prognostic factor in t (8;21) AML.