One pediatric study showed that the presence of FLT3-ITD mutations in the more primitive CD34+ CD33− cell population was heterogeneous (present in approximately 80% of ITD-positive AML patients), and conferred a worse prognosis compared to patients in which the ITD mutations was only present in CD34+ CD33+ cells (47). This evidence concerns the gene FLT3 and acute myeloid leukemia.