Two recent independent studies have determined that a V617F mutation of the JAK2 gene is present in many patients afflicted with MPDs (Baxter, E.J., et. al., Lancet 2005: 365: 1054-61) (Levine, et. al., Cancer Cell 2005: 7(4): 387-97). These studies demonstrated that a majority of patients with polycythemia vera, and a significant number of patients (up to 50%) with essential thrombocythemia and myeloid metaplasia with myelofibrosis have a clonal acquired somatic V617F JAK2 activating mutation.
