A (15-17)-TRANSLOCATION NOT ASSOCIATED WITH ACUTE PROMYELOCYTIC LEUKEMIA

We report a woman with acute myeloid leukaemia (AML) type M2 according to FAB classification, showing a t(15;17) apparently identical to tha t of acute promyelocytic leukaemia (APL) on conventional cytogenetic a nalysis. Fluorescence in situ hybridization (FISH) using cosmidic prob es specific for RAR alpha and PML regions did not show a fusion signal as in APL. The breakpoints were assigned to 15q24.3 and 17q21.1. Deta iled molecular analyses did not reveal any involvement of RAR alpha an d PML genes. The patient was resistant to several front-line AML treat ments and to all-trans retinoic acid (ATRA). These findings reinforce FISH and RT-PCR as useful tools for the characterization of a t(15;17) as the translocation specifically associated with APL.