Monocytic and myelomonocytic AML subtypes as defined by the French-American-British (FAB) classification (AML M4 and M5) and patients with FLT3-ITD mutations, and abnormalities involving the MLL gene on 11q23 have been identified as risk factors for hyperleukocytosis [5,15,16,17]. Here, FLT3 is linked to acute myeloid leukemia.