We show that midostaurin, like the dual FLT3/SYK inhibitors, R406 (tamatinib), and R788 (fostamatinib) [26], inhibits SYK in cell-based models of FLT3-ITD- and activated SYK-driven leukemia to a greater extent than highly targeted inhibitors of FLT3. This evidence concerns the gene FLT3 and leukemia.