In addition, for MPN, certain mutations such as JAK2 V617F or exon 12 mutation satisfy diagnostic criteria to help establish a diagnosis of MPN [5]; mutations in ASXL1, SRSF2, EZH2, IDH1, and IDH2 categorize patients to high molecular risk in Primary Myelofibrosis (PMF) [6]; and mutations in IDH2, U2AF1, EZH2, TP53, SH2B3, and SF3B1 indicate adverse prognostic value in Essential Thrombocythemia (ET) and Polycythemia Vera (PV) [7, 8]. The gene discussed is U2AF1; the disease is essential thrombocythemia.