The Development and Use of Janus Kinase 2 Inhibitors for the Treatment of Myeloproliferative Neoplasms

2017 ◽  
Vol 31 (4) ◽  
pp. 613-626 ◽  
Author(s):  
Gabriela S. Hobbs ◽  
Sarah Rozelle ◽  
Ann Mullally
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Janus Kinase ◽  
Janus Kinase 2

scholarly journals Complex molecular genetic diagnostic algorithm in the diagnosis of myeloproliferative neoplasms

2014 ◽  
Vol 155 (52) ◽  
pp. 2074-2081 ◽  
Author(s):  
Tünde Krähling ◽  
Katalin Balassa ◽  
Nóra Meggyesi ◽  
András Bors ◽  
Judit Csomor ◽  
...  
Keyword(s):  
Triple Negative ◽  
Myeloproliferative Neoplasms ◽  
Philadelphia Chromosome ◽  
Molecular Techniques ◽  
Janus Kinase ◽  
Driver Mutations ◽  
Similar Distribution ◽  
Janus Kinase 2 ◽  
Chain Reactions ◽  
Thrombopoietin Receptor

Introduction: Mutations in Janus kinase 2, calreticulin and thrombopoietin receptor genes have been identified in the genetic background of Philadelphia chromosome negative, “classic” myeloproliferative neoplasms. Aim: The aim of the authors was to identify driver mutations in a large myeloproliferative cohort of 949 patients. Method: A complex array of molecular techniques (qualitative and quantitative allele-specific polymerase chain reactions, fragment analyzes, high resolution melting and Sanger sequencing) was applied. Results: All 354 patients with polycythemia vera carried Janus kinase 2 mutations (V617F 98.6%, exon 12: 1.4%). In essential thrombocythemia (n = 468), the frequency of V617F was 61.3% (n = 287), that of calreticulin 25.2% (n = 118), and that of thrombopoietin receptor mutations 2.1% (n = 10), while 11.3% (n = 53) were triple-negative. Similar distribution was observed in primary myelofibrosis (n = 127): 58.3% (n = 74) V617F, 23.6% (n = 30) calreticulin, 6.3% (n = 8) thrombopoietin receptor mutation positive and 11.8% (n = 15) triple-negative. Conclusions: The recent discovery of calreticulin gene mutations led to definite molecular diagnostics in around 90% of clonal myeloproliferative cases. Orv. Hetil., 2014, 155(52), 2074–2081.

scholarly journals Platelet Dysfunction and Thrombosis in JAK2 V617F -Mutated Primary Myelofibrotic Mice

2020 ◽  
Vol 40 (10) ◽  
Author(s):  
Shinobu Matsuura ◽  
Cristal R. Thompson ◽  
Mostafa Elmokhtra Belghasem ◽  
Roelof H. Bekendam ◽  
Andrew Piasecki ◽  
...  
Keyword(s):  
Mouse Model ◽  
Platelet Activation ◽  
Vascular Injury ◽  
Thrombus Formation ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
Dense Granule ◽  
Janus Kinase ◽  
Moderate Increase ◽  
Janus Kinase 2

Objective: The risk of thrombosis in myeloproliferative neoplasms, such as primary myelofibrosis varies depending on the type of key driving mutation (JAK2 [janus kinase 2], CALR [calreticulin], and MPL [myeloproliferative leukemia protein or thrombopoietin receptor]) and the accompanying mutations in other genes. In the current study, we sought to examine the propensity for thrombosis, as well as platelet activation properties in a mouse model of primary myelofibrosis induced by JAK2 V617F (janus kinase 2 with valine to phenylalanine substitution on codon 617) mutation. Approach and Results: Vav1-hJAK2 V617F transgenic mice show hallmarks of primary myelofibrosis, including significant megakaryocytosis and bone marrow fibrosis, with a moderate increase in red blood cells and platelet number. This mouse model was used to study responses to 2 models of vascular injury and to investigate platelet properties. Platelets derived from the mutated mice have reduced aggregation in response to collagen, reduced thrombus formation and thrombus size, as demonstrated using laser-induced or FeCl 3 -induced vascular injury models, and increased bleeding time. Strikingly, the mutated platelets had a significantly reduced number of dense granules, which could explain impaired ADP secretion upon platelet activation, and a diminished second wave of activation. Conclusions: Together, our study highlights for the first time the influence of a hyperactive JAK2 on platelet activation-induced ADP secretion and dense granule homeostasis, with consequent effects on platelet activation properties.

High Risk Janus Kinase 2 V617F Allele Burden in a Seven-Year Cohort of Patients with Myeloproliferative Neoplasms

2021 ◽  
Vol 67 (11/2021) ◽  
Author(s):  
Moses Chatambudza ◽  
Lindiwe Skhosana ◽  
Irene Ketseoglou ◽  
Tracey Wiggill
Keyword(s):  
High Risk ◽  
Myeloproliferative Neoplasms ◽  
Janus Kinase ◽  
Janus Kinase 2 ◽  
Allele Burden

Should We Screen for Janus Kinase 2 V617F Mutation in Cerebral Venous Thrombosis?

2017 ◽  
Vol 44 (3-4) ◽  
pp. 97-104 ◽  
Author(s):  
Matthias Lamy ◽  
Paola Palazzo ◽  
Pierre Agius ◽  
Jean Claude Chomel ◽  
Jonathan Ciron ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Cerebral Venous Thrombosis ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Janus Kinase ◽  
Jak2 V617f Mutation ◽  
Janus Kinase 2 ◽  
Jak2 Mutation ◽  
Venous Thromboembolic Events ◽  
V617f Mutation

Background: The presence of Janus Kinase 2 (JAK2) V617F mutation represents a major diagnostic criterion for detecting myeloproliferative neoplasms (MPN) and even in the absence of overt MPN, JAK2 V617F mutation is associated with splanchnic vein thrombosis. However, the actual prevalence and diagnostic value of the JAK2 V617F mutation in patients with cerebral venous thrombosis (CVT) are not known. The aims of this study were to assess the prevalence of JAK2 V617F mutation in a large group of consecutive CVT patients, to detect clinical, biological, and radiological features associated with the mutation, and to determine the long-term venous thrombosis recurrence rate in CVT patients with JAK2 mutation but without overt MPN in order to recommend the best preventive treatment. Methods: This was a prospective study conducted on consecutive patients with a first-ever radiologically confirmed CVT. JAK2 V617F mutation analysis was assessed in all the study subjects. JAK2 V617F-positive patients were followed up to detect new venous thrombotic events. Results: Of the 125 included subjects, 7 were found to have JAK2 V617F mutation (5.6%; 95% CI 2.3-11.2). Older age (p = 0.039) and higher platelet count (p = 0.004) were independently associated with JAK2 V617F positivity in patients without overt MPN. During a mean follow-up period of 59 (SD 46) months, 2 JAK2 V617F-positive patients presented with 4 new venous thromboembolic events. Conclusions: Screening for the JAK2 V617F mutation in CVT patients seems to be useful even in the absence of overt MPN and/or in the presence of other risk factors for CVT because of its relatively high prevalence and the risk of thrombosis recurrence.

scholarly journals Megakaryocytic morphology in Janus kinase 2 V617F positive myeloproliferative neoplasm

2017 ◽  
Vol 06 (02) ◽  
pp. 075-078
Author(s):  
Shuchi Ghai ◽  
Sharada Rai
Keyword(s):  
Bone Marrow ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Janus Kinase ◽  
Jak2 V617f Mutation ◽  
Fisher Exact Test ◽  
Janus Kinase 2 ◽  
Bone Marrow Biopsies ◽  
V617f Mutation

Abstract Context: Alterations in megakaryocyte morphology are the hallmark of myeloproliferative neoplasms (MPNs). These neoplasm are also associated with Janus kinase 2 (JAK2) V617F mutation in nearly 95% patients with polycythemia vera (PV), 40% patients of essential thrombocythemia (ET) and 50% patients of myelofibrosis (MF). The utility of megakaryocyte morphology in these disorders in correlation with JAK2 V617F remains unresolved. Aims: The aim of the study was to assess the morphology of megakaryocytes in bone marrow aspirates (BMAs) and bone marrow biopsies of patients of BCR-ABL negative MPNs with JAK2 V617F mutation. Settings and Design: This study was a retrospective and prospective, hospital-based study undertaken for a period ranging from January 2011 to April 2015. Subjects and Methods: Assessment of morphological features of megakaryocytes in 15 BMAs and their respective biopsies which included seven cases of PV, three cases of ET, and five cases of MF with JAK2 V617F mutation. Statistical Analysis Used: Chi-square test and Fisher exact test were used to compare the different features of megakaryocytes. Software version SPSS 13.0 was used. Results: Megakaryocytes in ET were found to have characteristically large size with staghorn multinucleated nuclei and exhibiting large amount of cytoplasm. MF showed dense clustering of megakaryocytes with staghorn nucleus along with sinusoidal dilatation and intrasinusoidal hematopoiesis. PV showed loose and dense clustering of megakaryocytes with a predominance of cloud-like nuclei. Few of the megakaryocytic morphologic features showed overlap between MF and PV and between ET and early MF. Conclusions: Megakaryocytic morphology can aid in the accurate diagnosis of the different subcategories of MPNs. This would help in categorization of clinically suspicious patients of JAK2 V617F negative patients.

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