FLT3 and leukemia: Conversely, we analyzed MV4;11 (homozygous for the Flt3-ITD, high allelic ratio or “Flt3-ITDhighAR”) and MOLM-13 (heterogygous for the Flt3-ITD, low allelic ratio or “Flt3-ITDlowAR”), which express little (“dim”) and no Mer respectively, and have been used extensively as models of leukemia with Flt3-ITD mutations.