In hematological malignancies, the NPM1 gene is frequently combined with other genes to generate fusion proteins that retain the oligomerization domain in the N-terminus of NPM1, including NPM1-RARα in a subset of acute promyelocytic leukemia patients [3] and the rare NPM1-MLF1 [4] translocation, which is associated with the progression of myelodysplastic syndrome (MDS) to acute myeloid leukemia (AML). Here, NPM1 is linked to acute promyelocytic leukemia.