Expression ofFLT3and myeloid differentiation markers in T- and B-ALLs withMLLtranslocations. In contrast to the specific expression of FLT3 and other myeloid genes in MLL-rearranged B-ALLs, FLT3, Cyclin A1, and Serpin B1 were not up-regulated in MLL T-ALLs. A single, MLL-ENL—negative T-ALL case harboring an activating FLT3 internal tandem duplication expressed high levels of FLT3, Serpin B1, and other myeloid genes (Figure S3, supplemental material). Gene expression is reported in absolute fluorescence units.