FMS-like Tyrosine Kinase-3 Mutation in a Child with Standard-risk ALL and Normal Karyotype

Fms-like tyrosine kinase-3 is a receptor tyrosine kinase expressed by immature hematopoietic cells and is important for the normal development of stem cells and immune system. mutations of fms-like tyrosine kinase-3 have been detected in about 30% of patients with acute myelogenous leukemia and a small number of patients with acute lymphoblastic leukemia. the fms-like tyrosine kinase-3 mutations most often involve small tandem duplications of amino acids within the juxtamembrane domain of the receptor and are called internal tandem duplications. the other type of mutations in fms-like tyrosine kinase-3 is located in the activation loop of the second tyrosine kinase domain. multiple studies have shown that activating mutations of fms-like tyrosine kinase-3 are common in blasts from patients with acute myeloid leukemia but are rarely found in adult patients with acute lymphoblastic leukemia. in addition, activating flt3 mutations occur only rarely in t-all cases. here we report a 3-year-old girl with acute lymphoblastic leukemia who had a mutation in fms-like tyrosine kinase-3 / internal tandem duplications.