Arginine 595 is duplicated in patients with acute leukemias carrying internal tandem duplications of FLT3 and modulates its transforming potential.

FLT3-internal tandem duplications (FLT3-ITDs) comprise a heterogeneous group of mutations in patients with acute leukemias that are prognostically important. To characterize the mechanism of transformation by FLT3-ITDs, we sequenced the juxtamembrane region (JM) of FLT3 from 284 patients with acute leukemias. The length of FLT3-ITDs varied from 2 to 42 amino acids (AAs) with a median of 17 AAs.