Flt-3/CD135

Flt-3, or CD135, is a class III receptor tyrosine kinase whose ligand, FLT3 ligand, is a key regulator of early hematopoiesis. The receptor is expressed on multipotent progenitors and early myeloid and lymphoid precursors, where FLT3L engagement supports their expansion and survival. FLT3 is also the most frequently mutated gene in acute myeloid leukemia: internal tandem duplications in the juxtamembrane domain or activating point mutations in the activation loop, most commonly D835, drive constitutive signaling and adverse prognosis. This has made FLT3 a validated oncology target, and the inhibitors midostaurin, gilteritinib and quizartinib are approved or advanced in AML therapy.