JAK2 and essential thrombocythemia: The association observed between presence of DTA mutation and thrombotic event in PV patients but not in the whole MPN series could be conditioned by the co-occurrence of a JAK2 mutation (since almost all patients with PV have JAK2 mutations compared to 50% in patients with MF, 60% in patients with SMF post-ET, and 48% in patients with ET in our series).