Exome sequencing of six Dnmt3aR882H/+ MPN/AMLs showed several somatic mutations in each MPN/AML, including in genes known to co-occur with DNMT3A mutations in human AML, such as Tet1, Setd2 and Cux1 (Supplementary Table 1). Here, CUX1 is linked to acute myeloid leukemia.