To assess the significance of MN1 expression as a marker for MRD detection in AML, the MN1 transcript amount was quantified during follow-up in 20 AML patients characterized by the presence of specific fusion-gene transcripts (15 CBFβ-MYH11 and 5 RUNX1-AML1), in 8 patients with NPM1 mutation and in and 13 AML patients (including 3 resistant cases) lacking additional molecular markers but monitored by making use of WT1 quantitative assessment, which we have previously demonstrated to strictly parallel fusion gene transcript behavior [6]. This evidence concerns the gene NPM1 and acute myeloid leukemia.