Low frequency of the TEL/AML1 fusion gene in acute lymphoblastic leukaemiain Spain

We report on a series of Spanish patients with acute lymphoblastic leukaemi a in whom the t(12;21) [TEL/AML1] translocation could not be identified wit h two sensitive techniques: reverse transcript-polymerase chain reaction (R T-PCR) and fluoroescence in-situ hybridization (FISH), 101 cases were analy sed: 38 children (29 B-cell precursor: nine T-cell precursor) and 63 adults (48 B-cell precursor: 15 T-cell precursor), Specific RT-PCR to amplify the TEL/AML1 fusion transcript was negative in all 101 cases. Moreover, all 38 paediatric samples were also negative by interphase FISH analysis for the presence of the TEL/AML1 fusion. These results suggest the existence of geo graphic/race variations in the genotype of acute lymphoblastic leukaemia (A LL).