Ras mutations were found in another assay system that utilized MOLM14 cells (an AML-M5 line having one wt FLT3 allele and one FLT3-ITD allele) made resistant to FLT3 inhibitors, CEP-5214 [20] and CEP-701 [21] following long-term exposure to these agents [15]. Here, FLT3 is linked to acute myeloid leukemia.