JAK2-V617F mutation and Philadelphia positive chronic myeloid leukemia.

JAK2 is a tyrosine kinase that plays an important role in the signaling pathways of many hematopoietic growth factor receptors. A single acquired point mutation – V617F – in JAK2 occurs in the great majority of patients with polycythemia vera (PV) and approximately half of the patients with idiopathic myelofibrosis (IMF) or essential thrombocythemia (ET). In contrast, the JAK2-V617F mutation is only rarely found in chronic myeloid leukemia (CML) but, recently, some authors have reported the coexistence of JAK2V617F and BCR/ABL+ in CML patients expressing the p210 BCR–ABL oncoprotein. Here, we report a CML patient with the expression of p210/b2a2 type BCR–ABL transcript and JAK2V617F mutation.