For rare cases of aCML with JAK2 V617F mutation (62, 187, 188), ruxolitinib, a JAK2 inhibitor approved by the FDA in intermediate- to high-risk MF and PV intolerant or resistant to HU, can be used (189, 190). The gene discussed is JAK2; the disease is atypical chronic myeloid leukemia, BCR-ABL1 negative.