title: Myeloproliferative neoplasms: contemporary diagnosis using histology and genetics.
abstract: The 2008 WHO classification system for hematological malignancies is comprehensive and includes histology and genetic information. Myeloid neoplasms are now classified into five categories: acute myeloid leukemia, myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), MDS/MPN, and myeloid and/or lymphoid malignancies associated with eosinophilia and PDGFR or FGFR1 rearrangements. MPN are subclassified into eight separate entities: chronic myelogenous leukemia, polycythemia vera, essential thrombocythemia, primary myelofibrosis, systemic mastocytosis, chronic eosinophilic leukemia not otherwise specified, chronic neutrophilic leukemia, and unclassifiable MPN. The diagnosis of chronic myelogenous leukemia requires the presence of BCR-ABL1, while its absence is required for all other MPN. Additional MPN-associated molecular markers include mutations of JAK2, MPL, TET2 and KIT. JAK2 V617F is found in most patients with polycythemia vera, essential thrombocythemia, or primary myelofibrosis and is, therefore, useful as a clonal marker in those settings. The diagnostic utility of MPL and TET2 mutations is limited by low mutational frequency. In systemic mastocytosis, presence of KIT D816V is expected but not essential for diagnosis. Chronic eosinophilic leukemia not otherwise specified should be distinguished from both PDGFR-rearranged or FGFR1-rearranged neoplasms and hypereosinophilic syndrome. We discuss histologic, cytogenetic and molecular changes in MPN and illustrate their integration into practical diagnostic algorithms.
authors.affiliation: Division of Hematology, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA. tefferi.ayalew@mayo.edu
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
authors.forename: Radek
authors.initials: R
authors.lastname: Skoda
authors.forename: James W
authors.initials: JW
authors.lastname: Vardiman
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000235:genetics; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis / Q000235:genetics; D009154:Mutation; D009190:Myelodysplastic Syndromes / Q000175:diagnosis / Q000235:genetics; D009196:Myeloproliferative Disorders / Q000145:classification / Q000175:diagnosis* / Q000235:genetics*; D011087:Polycythemia Vera / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000235:genetics; D013920:Thrombocythemia, Essential / Q000175:diagnosis / Q000235:genetics; D014944:World Health Organization
chemical_list: D014408:Biomarkers, Tumor; D020796:Receptor, Platelet-Derived Growth Factor alpha; D020797:Receptor, Platelet-Derived Growth Factor beta; D016044:Fusion Proteins, bcr-abl; D053614:Janus Kinase 2