Unlike imatinib in chronic myeloid leukemia (CML), where already 6 months of TKI treatment can result in a durable clinical response by reduction of the BCR::ABL1 transcript, JAK2 inhibitor short-term treatment does not induce a significant reduction in MPN-driving allele burden (18, 19). The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.