Patients with ET are usually risk-stratified according to the Revised International Prognostic Score for Thrombosis in ET (R-IPSET) [9] which accounts for age, presence of JAK2 mutation, and thrombosis history; high-risk patients (those with prior thrombosis or older than 60 years of age and with JAK2 mutation) receive IFN or HU. This evidence concerns the gene JAK2 and essential thrombocythemia.