Overexpression of AXL and its role in resistance to targeted and cytotoxic therapies have been shown in several different tumor types, including imatinib-resistant CML and gastrointestinal stromal tumors [80], AML with acquired resistance to FLT3 TKIs [81], cisplatin-resistant ovarian cancer [82], HER-2 positive breast cancer resistant to lapatinib [83], and rhabdomyosarcoma resistant to IGF1R inhibition [84]. This evidence concerns the gene FLT3 and acute myeloid leukemia.