Molecular and clinical features of the myeloproliferative neoplasm associated with JAK2 exon 12 mutations

• Published in: Blood Vol. 117; no. 10; pp. 2813 - 2816
• Main Authors: Passamonti, Francesco, Elena, Chiara, Schnittger, Susanne, Skoda, Radek C., Green, Anthony R., Girodon, François, Kiladjian, Jean-Jacques, McMullin, Mary Frances, Ruggeri, Marco, Besses, Carles, Vannucchi, Alessandro M., Lippert, Eric, Gisslinger, Heinz, Rumi, Elisa, Lehmann, Thomas, Ortmann, Christina A., Pietra, Daniela, Pascutto, Cristiana, Haferlach, Torsten, Cazzola, Mario
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 10-03-2011; Americain Society of Hematology
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Exons; Female; Hematologic and hematopoietic diseases; Humans; In Situ Hybridization; Janus Kinase 2 - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Leukocytosis - etiology; Leukocytosis - genetics; Male; Medical sciences; Middle Aged; Mutation; Polycythemia - etiology; Polycythemia - genetics; Polycythemia Vera - complications; Polycythemia Vera - genetics; Polycythemia Vera - mortality; Polymerase Chain Reaction; Thrombocytosis - etiology; Thrombocytosis - genetics; Young Adult; Myeloproliferative syndrome; Exon; Hematology; Enzyme; JAK2 protein tyrosine kinase; Transferases; Clinical form; Genetics; Hemopathy; Mutation; Protein-tyrosine kinase
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2010-11-316810

Although approximately 95% of patients with polycythemia vera (PV) harbor the V617F mutation in JAK2 exon 14, several mutations in exon 12 have been described in the remaining patients. We conducted a European collaborative study to define the molecular and clinical features of patients harboring these mutations. Overall, 106 PVs were recruited and 17 different mutations identified. Irrespective of the mutation, two-thirds of patients had isolated erythrocytosis, whereas the remaining subjects had erythrocytosis plus leukocytosis and/or thrombocytosis. Compared with JAK2 (V617F)-positive PV patients, those with exon 12 mutations had significantly higher hemoglobin level and lower platelet and leukocyte counts at diagnosis but similar incidences of thrombosis, myelofibrosis, leukemia, and death. In a multivariable analysis, age more than 60 years and prior thrombosis predicted thrombosis. These findings suggest that, despite the phenotypical difference, the outcome of JAK2 exon 12 mutations-positive PV is similar to that of JAK2 (V617F)-positive PV.