JAK2 and acquired polycythemia vera: Accordingly, we compared the JAK2 V617F allele burden between 107 ET and 55 PV patients with JAK2 V617F mutation and found that JAK2 V617F allele burden was much higher in PV patients[median(P25–P75): 45.02% (35.12%–54.22%)] than in ET patients [median(P25–P75): 28.23%(17.77%–41.66%)].