In Reply [to ’Comparing Apples and Oranges in Normal Karyotype Acute Myeloid Leukemia’ by Bruno C. Medeiros] [Letter]

We thank Medeiros for his interest in our recent study of Wilms? tumor 1 (WT1) mutations in acute myeloid leukemia. The data are broadly similar to an accompanying article by Paschka et al1 with regard to the frequency of WTI mutations in younger patients with acute myeloid leukemia with a normal karyotype, and to the adverse impact of such mutations independent of the mutational status of NPM1 and FLT3 internal tandem duplications (FLT3-ITDs). As noted by Medeiros, and in contrast to the study of Paschka et al, we chose not to include an analysis of the individual subsets of patients defined by the combination of the mutational status of NPM1 and FLT3-ITDs as part of our original submission. We were reluctant to present this data because we had seen no significant interaction between the impact of a WT1 mutation and the presence of an NPM1 mutation or an FLT3-ITD, and the individual subsets defined by these two parameters included too few patients with a WT1 mutation to facilitate robust interpretation.