Diagnostic and prognostic markers of AML such as KIT [4,5], FLT3 [6], CEBPA [7,8] and NPM1 [9] have been identified in both adult and paediatric AML, although few of the tumour antigens known in adult AML (recently reviewed in [10]) have been investigated in paediatric AML (reviewed in [11]). This evidence concerns the gene NPM1 and acute myeloid leukemia.