Somatic mutations in Additional sex comb-like 1(ASXL1) are frequently detected in various types of myeloid malignancies, including myelodysplastic syndromes (MDS, 14–23%) [23–29], chronic myelomonocytic leukemia (CMML, 40–49%) [23, 30], myeloproliferative neoplasms (MPN, 5–11%) [31–34], and acute myeloid leukemia (AML, 5–17%) [24, 35, 36]. The gene discussed is ASXL1; the disease is chronic myelomonocytic leukemia.