This may also explain the very limited effect of ruxolitinib for post-MPN sAML [7], from which these cell lines have been derived, as well as the inefficiency of ruxolitinib to reduce the allelic burden of JAK2-V617F mutation and to eradicate neoplastic cells with this mutation in treatment of MPNs [4]. The gene discussed is JAK2; the disease is myeloproliferative neoplasm.