We determined the allelic frequency of the JAK2-V617F mutation in DNA and assessed the expression levels of the mutant and wild-type JAK2 mRNA in granulocytes from 60 patients with essential thrombocythemia (ET) and 62 patients with polycythemia vera (PV) at the time of diagnosis. Using allele-specific quantitative polymerase chain reaction (qPCR), we detected JAK2-V617F in 75% of ET and 97% of...

JAK2 (Janus tyrosine kinase 2) is important for signalling through many cytokine receptors, and a gain-of-function JAK2 mutation in its pseudokinase domain, V617F, has been implicated in Philadelphia chromosome-negative myeloproliferative neoplasms. How this mutation hyperactivates JAK2 is poorly understood. In the present paper we report our findings that the V617F mutation has little effect o...

Janus kinase 2 (JAK2) is an important mediator of cytokine receptor signaling and plays a key role in the hematopoietic and immune responses. The acquired JAK2 C618R somatic mutation is detected in a subset of myeloproliferative disorders (MPDs) patients and presumed to be a biomarker for MPDs. However, how JAK2 C618R mutation causes MPDs is still unclear. Our results indicate that the amino ac...

OBJECTIVE JAK2 V617F, MPL W515L and JAK2 exon 12 mutations are novel acquired mutations that induce constitutive cytokine-independent activation of the JAK-STAT pathway in myeloproliferative disorders (MPD). The discovery of these mutations provides novel mechanism for activation of signal transduction in hematopoietic malignancies. This research was to investigate their prevalence in Chinese p...

BACKGROUND Myeloproliferative disorders (MPDs) represent a risk factor for thrombosis in the portal, mesenteric, and hepatic districts. OBJECTIVE We aimed to assess whether the Janus kinase 2 (JAK2) V617F mutation, an acquired mutation that occurs in MPD patients, is a risk factor for portal and mesenteric venous thrombosis (PMVT) independently of the presence of overt MPDs. PATIENTS AND ME...

Although a large proportion of patients with polycythemia vera (PV) harbor a valine-to-phenylalanine mutation at amino acid 617 (V617F) in the JAK2 signaling molecule, the stage of hematopoiesis at which the mutation arises is unknown. Here we isolated and characterized hematopoietic stem cells (HSC) and myeloid progenitors from 16 PV patient samples and 14 normal individuals, testing whether t...

CONTEXT Megakaryocytes are the "hallmark" of Philadelphia chromosome-negative myeloproliferative neoplasms, such as essential thrombocythemia, polycythemia vera, and primary myelofibrosis; their morphology in correlation with Janus kinase 2 (JAK2 V617F) mutation as well as clinical and laboratory parameters remains unknown. OBJECTIVE To assess the morphology of megakaryocytes in bone marrow b...

Treatment with Imatinib mesylate leads to molecular remission in majority of Philadelphia chromosome (Ph) positive Chronic Myeloid Leukemia (CML) cases. However, sometimes persistent anemia or evolving myelofibrosis is observed due to a co-existing Ph negative chronic Myelo Proliferative Disorder (CMPD) clone. Polycythemia vera (PV) is the most common Myelo Proliferative Disorder (MPD) coexisti...

The JAK2(V617F)mutation is recurrent in polycythemia vera and essential thrombocythemia, which are myeloproliferative neoplasms frequently associated with arterial and venous thromboembolism. It has also been reported as a marker for occult myeloproliferative disorder (MPD) in patients with splanchnic venous thrombosis. Limited data are available regarding the prevalence of the JAK2(V617F) muta...

Detection of the JAK2 p.V617F mutation and measurement of its allele burden can be performed using both peripheral blood (PB) and bone marrow (BM) samples from patients with myeloproliferative neoplasms (MPNs). However, the diagnostic accuracy of detecting the JAK2 p.V617F mutation and quantifying its allele burden in PB and BM samples has not been systematically compared. We retrospectively an...