TEL-AML1 FUSION IN ACUTE LYMPHOBLASTIC-LEUKEMIA OF ADULTS

A number of fusion genes have been identified by study of acquired chr omosomal translocations. Their detailed characterization has provided insights into mechanisms of leukaemogenesis and has enabled the develo pment of molecular methods to assist in the diagnosis and monitoring o f residual disease after treatment. The TEL-AML1 fusion gene is associ ated with a cryptic t(12;21)(p12;q22) translocation, and is the common est known genetic abnormality in childhood B-cell precursor acute lymp hoblastic leukaemia (ALL), occurring in about 25% of cases. We have us ed RT-PCR, followed by Southern blotting and direct sequencing, to est ablish the incidence of TEL-AML1 rearrangement in 131 adults with acut e leukaemia (101 with ALL and 30 with chronic myeloid leukaemia in bla stic crisis). Three patients were positive for TEL-AML1 transcripts. A ll three had common-ALL. All other patients were negative for TEL-AML1 . We conclude that the TEL-AML1 fusion gene is found in adult ALL, tho ugh less commonly than in children.