ASXL1 and myelodysplastic syndrome: Additional sex combs–like 1 (ASXL1) is one of the most frequently mutated genes across the spectrum of myeloid malignancies, including chronic myelomonocytic leukemia (1, 2), myelodysplastic syndrome (MDS) (3, 4), myeloproliferative neoplasms (MPNs) (5, 6), juvenile myelomonocytic leukemia (7, 8), and acute myeloid leukemia (AML) (9, 10).