FLT3 and acute myeloid leukemia: Resistance to commonly used tyrosine kinase inhibitors (TKIs) including sorafenib (Additional file 2: Table S8) in FLT3-ITD + AML patients, commonly occurs following the acquisition of a secondary point mutation at aspartic acid 835 in the kinase domain of FLT3-ITD (FLT3-ITD/D835V and FLT3-ITD/D835Y, henceforth referred to as “double mutant”) [37, 38].