ASXL1 and myeloproliferative neoplasm: Although the wild-type (WT) control animals did not develop any noticeable hematological malignancies, almost all Asxl1/Ezh2 double KO (dKO) mice succumbed to fatal MDS/MPN, associated with marked splenomegaly and extramedullary hematopoiesis in the presence of B-cell lymphoproliferative disorders (LPDs) in some animals (Figure 1D-H; supplemental Figure 1E-G; supplemental Table 2).