Identification of a transforming MYB-GATA1 fusion gene in acute basophilic leukemia: a new entity in male infants.

Acute basophilic leukemia(ABL) is a rare subtype of acute leukemiawith clinical features and symptoms related to hyperhistaminemia because of excessive growth of basophils. No known recurrent cytogenetic abnormality is associated with this leukemia. Rare cases of t(X;6)(p11;q23) translocation have been described but these were sporadic. We report here 4 cases of ABL with a t(X;6)(p11;q23) translocation occurring in male infants. Because of its location on chromosome 6q23, MYBwas a good candidate gene. Our molecular investigations, based on fluorescencein situ hybridizationand rapid amplificationof cDNA ends, revealed that the translocation generated a MYB- GATA1 fusion gene. Expression of MYB- GATA1in mouse lineage-negative cells committed them to the granulocyte lineage and blocked at an early stage of differentiation. Taken together, these results establish, for the first time, a link between a recurrent chromosomal translocationand the development of this particular subtype of infant leukemia.