The Burden of JAK2V617F Mutated Allele in Turkish Patients With Myeloproliferative Neoplasms

Abstract

Background: Studies regarding the impact of JAK2V617F allele burden on phenotypic properties and clinical course in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs) have reported variable results. We aimed to analyze the association of mutated JAK2V617F allele burden with laboratory characteristics and clinical phenotype in Turkish patients (107 essential thrombo-cythemia (ET) and 77 primary myelofibrosis (PMF)). Methods: Peripheral blood samples of 184 patients with Ph-negative MPNs were analyzed for JAK2V617F allele status and burden. JAK2 MutaScreen assay (Ipsogen, Luminy Biotech, Marseille, France) was used to detect the JAK2V617F status and quantitative JAK2V617F allele burdens in genomic DNA using TaqMan allelic discrimination. Results: Frequency of JAK2V617F-positive patients with high mu-tation load (allele burden > 50%) was higher in PMF compared to ET (23.4% and 4.7%, respectively; P = 0.001). We found significant association between ET patients with high JAK2V617F allele burden and lower hemoglobin (Hgb) and hematocrit (Hct), higher LDH lev-els and more prevalent massive splenomegaly (P = 0.001, P = 0.001, P = 0.012 and P = 0.015, respectively). ET patients with high muta-tion load displayed higher prevalence of bleeding compared to low mutation load and wild-type mutational status (P = 0.003). Rate of DVT was significantly higher in ET patients with mutant allele bur-den in upper half compared to lower half and wild-type (P = 0.029). We observed significant association between PMF patients with high JAK2V617F allele burden and higher Hgb, Hct levels and leukocyte counts (P = 0.003, P = 0.021 and P = 0.001, respectively). Conclusions: Our study demonstrated JAK2V617F allele burden correlates with clinical features in ET and PMF. We conclude quan-tification of JAK2V617F mutation contributes to the workup of Ph-negative MPNs.