FLT3 and leukemia: Interestingly, the hematopoietic cell kinase, normally expressed in the lymphoid and myeloid lineages of hemopoiesis (12), has been found to be enriched in dormant leukemia cells, interfering with the maturation of the FMS-like tyrosine kinase 3 (Flt3) and causing abnormal Flt3 signaling (13).