KIT and acute promyelocytic leukemia: Although the normal counterparts of these c-Kit+ APL cells within the normal hematopoietic hierarchy have remained unclear, accumulating evidences indicate that the APL LSC most likely originated from the malignant transformation of CMP and GMP, and to a lesser extent from MEP.24, 25, 26 Moreover, c-Kit+CD11b+ APL progenitors might developmentally resemble the unipotent monocytic or granulocytic progenitors or even promyelocytes.