AXL and acute myeloid leukemia: Treatment of midostaurin-resistant MOLM-13 (FLT3-ITD+) AML cells with the AXL inhibitor TP-0903 or soluble AXL chimeric protein Axl-Fc restored sensitivity to both midostaurin and quizartinib, suggesting an important role of AXL in the resistance of FLT3-ITD+ AML cells against the FLT3 inhibitors.