title: JAK2 mutation in essential thrombocythaemia: clinical associations and long-term prognostic relevance.
abstract: Clinical correlates and long-term prognostic relevance of the JAK2(V617F) mutation was studied in 150 patients with essential thrombocythaemia (ET) from a single institution and followed for a median of 11.4 years. During this period, thrombotic complications were documented in 62 patients (41.3%) and transformation into acute myeloid leukaemia (AML), polycythaemia vera (PV), or myelofibrosis with myeloid metaplasia (MMM) occurred in 4 (2.7%), 8 (5.3%), and 15 (10%) patients, respectively. JAK2(V617F) was detected in either archived bone marrow or blood cells from 73 patients (48.7%) but none were homozygous for the mutant allele. Parameters at diagnosis that were significantly associated with the presence of JAK2(V617F) included advanced age and higher counts of both haemoglobin and leucocytes. During follow-up, patients with the mutation were more likely to transform into PV but the incidences of AML, MMM, or thrombotic events were similar between patients with and without the mutation. Multivariate analysis identified advanced age, higher haemoglobin level, and thrombosis history but not the presence of JAK2(V617F) as independent predictors of inferior survival. Therefore, although the presence of JAK2(V617F) in ET appears to promote a PV phenotype, it might not carry treatment-relevant information.
authors.affiliation: Division of Hematology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Alexandra P
authors.initials: AP
authors.lastname: Wolanskyj
authors.forename: Terra L
authors.initials: TL
authors.lastname: Lasho
authors.forename: Susan M
authors.initials: SM
authors.lastname: Schwager
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: McClure
authors.forename: Martha
authors.initials: M
authors.lastname: Wadleigh
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Lee
authors.forename: D Gary
authors.initials: DG
authors.lastname: Gilliland
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D053614:Janus Kinase 2; D015470:Leukemia, Myeloid, Acute / Q000235:genetics; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017354:Point Mutation; D011087:Polycythemia Vera / Q000235:genetics; D055728:Primary Myelofibrosis / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012307:Risk Factors; D013920:Thrombocythemia, Essential / Q000235:genetics*; D013927:Thrombosis / Q000150:complications
chemical_list: D006454:Hemoglobins; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2