FLT3-ITD and its current role in acute myeloid leukaemia.

FMS-like tyrosine kinase 3 (FLT3) is a proto-oncogene involved in crucial steps of haematopoiesis such as proliferation, differentiation and survival. In recent years, FLT3 has been an important marker in different haematological malignancies, highlighting in acute myeloid leukaemia, where FLT3 mutations have been associated with the clinical prognosis, treatment and survival of patients. The most common form of FLT3 mutation is an internal tandem duplication (ITD) that promotes ligand-independent auto-phosphorylation and constitutive activation of the receptor. FLT3-ITD has been strongly associated with a bad prognosis, leukocytosis, high blast counts, increased risk of relapse and shorter overall survival. In order to improve the clinical condition of FLT3-ITD-positive patients, several FLT3 inhibitors have been developed showing variable results. Currently, the main challenges to be overcome are the different forms of resistance to FLT3 inhibitors. Thus, the purpose of this review is to present, in a general way, the current role that FLT3-ITD mutation plays in patients with AML, with a particular emphasis on the molecular mechanisms associated with clinical prognosis, treatment, and survival of patients.