Coexistence of BCR–ABL1 reassortment and JAK2 V617F mutation in chronic myeloid leukaemia

Myeloproliferative neoplasms (MPNs) can be classified into two major categories, namely chronic myeloid leukaemia (CML) and Philadelphia-negative MPNs (PN-MPNs). BCR- ABL1 reassortment is an irreplaceable indicator for the diagnosis of typical CML, while the V617F mutation on the Janus kinase 2 (JAK2) gene is common in PN-MPNs patients. Generally, these two genetic abnormalities are considered unable to coexist. We report a patient with CML who had both genetic changes, suggesting that when tyrosine kinase inhibitors (TKIs) monotherapy cannot obtain satisfactory treatment outcomes in CML patients, another possibility besides disease progression is a mutation on the JAK2 V617F gene.