FLT3 and acute myeloid leukemia: AML with low FLT3 allelic ratios (< 0.5) is currently classified by the European LeukemiaNet (ELN) as favorable risk; however, the majority of the data showing an adverse risk associated with high FLT3–ITD allelic ratio involved patients who did not receive FLT3 TKIs as part of the treatment [28, 29].