To the editor: KMT2E-ASNS: a novel relapse-specific fusion gene in early T-cell precursor acute lymphoblastic leukemia

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is arecentlycharacterizedsubtypeaccountingforupto15%ofchildhoodT-cellacutelymphoblasticleukemia(T-ALL). 1-3 This heterogeneous subgroup shows a distinctive immature immunophenotype characterized by the differential expression of cell surface markers during T-cell development. 2,4 ETP-ALL has been associated with a poor prognosis 2-6 in both pediatric and adult patients, although this was debated in other studies. 7-9 ETP-ALLs are associated with multiple rearrangements affecting gene-coding regions, quite possibly with a bearing on the formation of novel chimeric fusion genes, 2,4,10,11 for which the clinical signi fi cance remainsasyetlargelyunknown.InordertobetterunderstandthefactorsleadingtochildhoodETP-ALLrelapse,thewholetranscriptomeof 2 ETP-ALL patients was investigated with a view toward identifying relapse-speci fi c rearrangements.

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