JAK2 and acquired polycythemia vera: Current management of PV includes phlebotomy and low-dose aspirin as first-line treatment, with the addition of cytoreductive therapy (hydroxyurea [HU] or pegylated IFN) recommended for patients at a higher risk of thrombosis, and ruxolitinib (a JAK1 and JAK2 inhibitor) as second-line treatment [8–11].