ASXL1 is mutationally altered in several malignant myeloid diseases, including myeloproliferative neoplasms (MPNs; ∼10-15%), myelodysplastic syndromes (MDS; ∼15-25%), chronic myelomonocytic leukemia (CMML; ∼45%), and de novo (6.5%) or secondary (30%) cases of acute myeloid leukemia (AML) (Abdel-Wahab et al., 2011; Bejar et al., 2011; Boultwood et al., 2010a,b; Gelsi-Boyer et al., 2012, 2010; Inoue et al., 2013). This evidence concerns the gene ASXL1 and chronic myelomonocytic leukemia.