Indeed, previous studies showed that leukemic cells with low PP2A activity were sensitive to cell death induced by the PP2A-activating drug (PAD), FTY720 [32], and FLT3-ITD cells were more sensitive to inhibition of proliferation by FTY720 than were FLT3-WT AML cells [11]. This evidence concerns the gene FLT3 and acute myeloid leukemia.