In another study of 8 MPN patients with concurrent BCR-ABL1 fusion and JAK2 V617F/CALR mutations,[6] only 4 patients achieved an optimal response after imatinib treatment, whereas 3 developed imatinib resistance, 2 of whom had BCR-ABL1 kinase domain mutations. The gene discussed is JAK2; the disease is myeloproliferative neoplasm.