title: [Clinical significance of the quantification of JAK2V617F allele burden in classical Ph-negative myeloproliferative neoplasms].
abstract: OBJECTIVE
  Our study has investigated the presence of the mutation V617F in the JAK2 gene in patients diagnosed with chronic myeloproliferative neoplasms (MPNs). Furthermore, we determined if JAK2 (V617F) allelic burden associates with a specific clinical phenotype and if its quantification can be used as a marker to predict outcome and complications in patients with MPNs.
  
  
  METHODS
  A retrospective observational study was conducted from 1987 to 2011 in the Haematology Department of La Paz University Hospital. The allelic burden was measured in 114 patients diagnosed with MPNs: 39 polycythemia vera (PV) patients, 71 essential thrombocythaemia patients and 6 primary myelofibrosis patients. The quantitative real-time polymerase chain reaction (qRT-PCR) technology was used to determinate the percentage of mutated alleles in peripheral blood neutrophils. Patients were divided in 2 groups: heterozygous if the result was≤50% of the tested cells, and homozygous if it was positive in>50% of the cells.
  
  
  RESULTS
  Sixty-nine patients were positive for the JAK2 mutation and 45 were negative. Among those positive, the mutation was associated with arterial thrombosis. In addition, we demonstrate in the homozygous group that the V617F mutation is associated to PV, advanced age, leukocytosis, marked haematopoiesis and splenomegaly.
  
  
  CONCLUSIONS
  The presence of V617F mutation is associated with a higher incidence of thrombosis, leukocytosis and splenomegaly. The identification of mutation on the JAK2 gene could help in a better definition of evolution and prognostic stratification of the myeloproliferative disorders.
authors: Servicio de Hematología, Hospital Universitario La Paz, Madrid, Spain. anak534@gmail.com
authors: Ana Esther
authors: AE
authors: Kerguelén Fuentes
authors: Dolores
authors: D
authors: Hernández-Maraver
authors: Luis
authors: L
authors: Lombardia
authors: Miguel Angel
authors: MA
authors: Canales Albendea
authors: Ana
authors: A
authors: Rodriguez de la Rúa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009196:Myeloproliferative Disorders / Q000150:complications / Q000175:diagnosis / Q000235:genetics*; D010641:Phenotype; D017354:Point Mutation; D011087:Polycythemia Vera / Q000150:complications / Q000175:diagnosis / Q000235:genetics; D055728:Primary Myelofibrosis / Q000150:complications / Q000175:diagnosis / Q000235:genetics; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D012189:Retrospective Studies; D013920:Thrombocythemia, Essential / Q000150:complications / Q000175:diagnosis / Q000235:genetics
chemical_list: D005819:Genetic Markers; C507924:JAK2 protein, human; D053614:Janus Kinase 2