FLT3 Ile836del and FLT3 Ile836Met+Arg induce IL-3–independent growth of Ba/F3 cells. Ba/F3 cells were stably transfected with WT or mutated FLT3 constructs. Mutant FLT3-transformed Ba/F3 cells were cultured in the absence of IL-3 and FL. FLT3 WT-transfected cells were grown with or without FL (100 ng/mL) as a control. Proliferation was determined daily by a colorimetric tetrazolium salt (MTS) assay. Data represent values ± SD of triplicates.