Impact of JAK2V617F Mutational Status on Phenotypic Features in Essential Thrombocythemia and Primary Myelofibrosis.
OBJECTIVE
The JAK2V617F mutation is present in the majority of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). The impact of this mutation on disease phenotype in ET and PMF is still a matter of discussion. This study aims to determine whether there are differences in clinical presentation and disease outcome between ET and PMF patients with and without the JAK2V617F mutation.


METHODS
In this single-center study, a total of 184 consecutive Philadelphia-negative chronic myeloproliferative neoplasms, 107 cases of ET and 77 cases of PMF, were genotyped for JAK2V617F mutation using the JAK2 Ipsogen MutaScreen assay, which involves allele-specific polymerase chain reaction.


RESULTS
ET patients positive for JAK2V617F mutation had higher hemoglobin (Hb) and hematocrit (Hct) levels, lower platelet counts, and more prevalent splenomegaly at diagnosis compared to patients negative for the JAK2V617F mutation, but rates of major thrombotic events, arterial thrombosis, and venous thrombosis were comparable between the groups. At presentation, PMF patients with JAK2V617F mutation had significantly higher Hb and Hct levels and leukocyte counts than patients without the mutation. Similar to the findings of ET patients, thromboembolic rates were similar in PMF patients with and without theJAK2V617F mutation. For ET and PMF patients, no difference was observed in rates of death with respect to JAK2V617F mutational status. Moreover, leukemic transformation rate was not different in our PMF patients with and without JAK2V617F mutation.


CONCLUSIONS
We conclude that JAK2V617F-mutated ET patients express a polycythemia vera-like phenotype and JAK2V617F mutation in PMF patients is associated with a more pronounced myeloproliferative phenotype.
İstanbul University İstanbul Faculty of Medicine, Department of Internal Medicine, Division of Hematology, İstanbul, Turkey, E-mail: ipekyon@istanbul.edu.tr.
İpek
İ
Yönal
Aynur
A
Dağlar-Aday
Başak
B
Akadam-Teker
Ceylan
C
Yılmaz
Meliha
M
Nalçacı
Akif Selim
AS
Yavuz
Fatma Deniz
FD
Sargın
D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D001853:Bone Marrow / Q000473:pathology; D003062:Codon; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D055728:Primary Myelofibrosis / Q000175:diagnosis* / Q000235:genetics*; D013163:Splenomegaly; D013920:Thrombocythemia, Essential / Q000175:diagnosis* / Q000235:genetics*
D003062:Codon; D053614:Janus Kinase 2