title: JAK2V617F mutation is common in old patients with polycythemia vera and essential thrombocythemia.
abstract: BACKGROUND
  JAK2V617F mutation occurs in 90% of polycythemia vera (PV) and in 50% of essential thrombocythemia (ET) patients.
  
  
  METHODS
  253 consecutive patients affected by myeloproliferative disorders (MPD, 121 PV, 132 ET) were evaluated and stratified in 4 age groups: 18-39, 40-59, 60-75 and over 75 years (>75). The JAK2V617F mutation was searched and its allele burden was evaluated.
  
  
  RESULTS
  The percentage of mutated patients increased progressively with age mainly in patients >75 (p=0.0015 vs 18-39, p=0.0021 vs 40-59 and p=0.012 vs 60-75). We also found a progressive increase in allele burden with age (R2=0.042). Thrombotic events were more common in patients carrying the mutation in comparison with wild type (WT) (p=0.006, coefficient risk 1.94). No differences in the percentage of patients carrying the JAK2V617F mutation were found, in spite of different follow-up durations (<5 yrs, 5-10 yrs, 10-15 yrs, >15 yrs). The JAK2V617F allele burden was similar in patients with (57 ± 31%) and without (45 ± 26%) long-term hydroxyurea treatment.
  
  
  CONCLUSIONS
  JAK2V617F mutation is more common in old than in young patients with MPD. Older patients have an higher allele burden.
authors.affiliation: Department of Medical and Surgical Sciences, University of Padova Medical School, Padova, Italy. marialuigia.randi@unipd.it
authors.forename: Maria Luigia
authors.initials: ML
authors.lastname: Randi
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ruzzon
authors.forename: Fabiana
authors.initials: F
authors.lastname: Tezza
authors.forename: Margherita
authors.initials: M
authors.lastname: Scapin
authors.forename: Elena
authors.initials: E
authors.lastname: Duner
authors.forename: Raffaella
authors.initials: R
authors.lastname: Scandellari
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Fabris
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011087:Polycythemia Vera / Q000235:genetics*; D013920:Thrombocythemia, Essential / Q000235:genetics*
chemical_list: C507924:JAK2 protein, human; D053614:Janus Kinase 2