Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with essential thrombocythemia may carry JAK2 (V617F), an MPL substitution, or a calreticulin gene (CALR) mutation. We studied biologic and clinical features of essential thrombocythemia according to JAK2 or CALR mutation status and in relation to those of polycythemia vera. The mutant allele burden was lower in JAK2-mutated than in CALR-mutated essential thrombocythemia. Patients with JAK2 (V617F) were older, had a higher hemoglobin level and white blood cell count, and lower platelet count and serum erythropoietin than those with CALR mutation. Hematologic parameters of patients with JAK2-mutated essential thrombocythemia or polycythemia vera were related to the mutant allele burden. While no polycythemic transformation was observed in CALR-mutated patients, the cumulative risk was 29% at 15 years in those with JAK2-mutated essential thrombocythemia. There was no significant difference in myelofibrotic transformation between the 2 subtypes of essential thrombocythemia. Patients with JAK2-mutated essential thrombocythemia and those with polycythemia vera had a similar risk of thrombosis, which was twice that of patients with the CALR mutation. These observations are consistent with the notion that JAK2-mutated essential thrombocythemia and polycythemia vera represent different phenotypes of a single myeloproliferative neoplasm, whereas CALR-mutated essential thrombocythemia is a distinct disease entity.
...
PMID:JAK2 or CALR mutation status defines subtypes of essential thrombocythemia with substantially different clinical course and outcomes. 2462 49

Disease-specific mutations facilitate diagnostic precision and drug target discovery. In myeloproliferative neoplasms (MPN), this is best exemplified by the chronic myeloid leukemia-associated BCR-ABL1. No other mutation in MPN has thus far shown a similar degree of diagnostic accuracy or therapeutic relevance. However, JAK2 and KIT mutations are detected in more than 90% of patients with polycythemia vera and systemic mastocytosis, respectively, and are therefore used as highly sensitive clonal markers in these diseases. JAK2 and MPL mutations also occur in essential thrombocythemia (ET) and primary myelofibrosis (PMF), but their diagnostic value is limited by suboptimal sensitivity and specificity. The molecular diagnostic gap in JAK2/MPL-unmutated ET/PMF is now partially addressed by the recent discovery of calreticulin (CALR) mutations in the majority of such cases. However, bone marrow morphology remains the central diagnostic platform and is essential for distinguishing ET from prefibrotic PMF and diagnosing patients those do not express JAK2, MPL or CALR (triple-negative). The year 2013 was also marked by the description of CSF3R mutations in the majority of patients with chronic neutrophilic leukemia (CNL). Herein, we argue for the inclusion of CALR and CSF3R mutations in the World Health Organization classification system for ET/PMF and CNL, respectively.
 ...
PMID:An overview on CALR and CSF3R mutations and a proposal for revision of WHO diagnostic criteria for myeloproliferative neoplasms. 2444 Dec 92

Somatic mutations in the calreticulin (CALR) gene were recently discovered in patients with sporadic essential thrombocythemia (ET) and primary myelofibrosis (PMF) lacking JAK2 and MPL mutations. We studied CALR mutation status in familial cases of myeloproliferative neoplasm. In a cohort of 127 patients, CALR indels were identified in 6 of 55 (11%) subjects with ET and in 6 of 20 (30%) with PMF, whereas 52 cases of polycythemia vera had nonmutated CALR. All CALR mutations were somatic, found in granulocytes but not in T lymphocytes. Patients with CALR-mutated ET showed a higher platelet count (P = .017) and a lower cumulative incidence of thrombosis (P = .036) and of disease progression (P = .047) compared with those with JAK2 (V617F). In conclusion, a significant proportion of familial ET and PMF nonmutated for JAK2 carry a somatic mutation of CALR.
...
PMID:CALR exon 9 mutations are somatically acquired events in familial cases of essential thrombocythemia or primary myelofibrosis. 2455 79

Our understanding of the genetic basis of myeloproliferative neoplasms began in 2005, when the JAK2 (V617F) mutation was identified in polycythemia vera, essential thrombocythemia, and primary myelofibrosis. JAK2 exon 12 and MPL exon 10 mutations were then detected in subsets of patients, and subclonal driver mutations in other genes were found to be associated with disease progression. Recently, somatic mutations in the gene CALR, encoding calreticulin, have been found in most patients with essential thrombocythemia or primary myelofibrosis with nonmutated JAK2 and MPL. The JAK-STAT pathway appears to be activated in all myeloproliferative neoplasms, regardless of founding driver mutations. These latter, however, have different effects on clinical course and outcomes. Thus, evaluation of JAK2, MPL, and CALR mutation status is important not only for diagnosis but also for prognostication. These genetic data should now also be considered in designing clinical trials.
...
PMID:From Janus kinase 2 to calreticulin: the clinically relevant genomic landscape of myeloproliferative neoplasms. 2478 75

The Polycythemia Vera Study Group (PVSG) and WHO classifications distinguished the Philadelphia (Ph(1)) chromosome-positive chronic myeloid leukemia from the Ph(1)-negative myeloproliferative neoplasms (MPN) essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (MF) or primary megakaryocytic granulocytic myeloproliferation (PMGM). Half of PVSG/WHO-defined ET patients show low serum erythropoietin levels and carry the JAK2(V617F) mutation, indicating prodromal PV. The positive predictive value of a JAK2(V617F) PCR test is 95% for the diagnosis of PV, and about 50% for ET and MF. The WHO-defined JAK2(V617F)-positive ET comprises three ET phenotypes at clinical and bone marrow level when the integrated WHO and European Clinical, Molecular and Pathological (ECMP) criteria are applied: normocellular ET (WHO-ET), hypercellular ET due to increased erythropoiesis (prodromal PV) and hypercellular ET associated with megakaryocytic granulocytic myeloproliferation (EMGM). Four main molecular types of clonal MPN can be distinguished: JAK2(V617F)-positive ET and PV; JAK2 wild-type ET carrying the MPL(515); mutations in the calreticulin (CALR) gene in JAK2/MPL wild-type ET and MF, and a small proportion of JAK2/MPL/CALR wild-type ET and MF patients. The JAK2(V617F) mutation load is low in heterozygous normocellular WHO-ET. The JAK2(V617F) mutation load in hetero-/homozygous PV and EMGM is clearly related to MPN disease burden in terms of splenomegaly, constitutional symptoms and fibrosis. The JAK2 wild-type ET carrying the MPL(515) mutation is featured by clustered small and giant megakaryocytes with hyperlobulated stag-horn-like nuclei, in a normocellular bone marrow (WHO-ET), and lacks features of PV. JAK2/MPL wild-type, CALR mutated hypercellular ET associated with PMGM is featured by dense clustered large immature dysmorphic megakaryocytes and bulky (cloud-like) hyperchromatic nuclei, which are never seen in WHO-ECMP-defined JAK2(V617F) mutated ET, EMGM and PV, and neither in JAK2 wild-type ET carrying the MPL(515) mutation. Two thirds of JAK2/MPL wild-type ET and MF patients carry one of the CALR mutations as the cause of the third distinct MPN entity. WHO-ECMP criteria are recommended to diagnose, classify and stage the broad spectrum of MPN of various molecular etiologies.
 ...
PMID:Changing concepts of diagnostic criteria of myeloproliferative disorders and the molecular etiology and classification of myeloproliferative neoplasms: from Dameshek 1950 to Vainchenker 2005 and beyond. 2511 92

With the discovery of the JAK2V617F mutation in patients with Philadelphia chromosome-negative (Ph(-)) myeloproliferative neoplasms (MPNs) in 2005, major advances have been made in the diagnosis of MPNs, in understanding of their pathogenesis involving the JAK/STAT pathway, and finally in the development of novel therapies targeting this pathway. Nevertheless, it remains unknown which mutations exist in approximately one-third of patients with non-mutated JAK2 or MPL essential thrombocythemia (ET) and primary myelofibrosis (PMF). At the end of 2013, two studies identified recurrent mutations in the gene encoding calreticulin (CALR) using whole-exome sequencing. These mutations were revealed in the majority of ET and PMF patients with non-mutated JAK2 or MPL but not in polycythemia vera patients. Somatic 52-bp deletions (type 1 mutations) and recurrent 5-bp insertions (type 2 mutations) in exon 9 of the CALR gene (the last exon encoding the C-terminal amino acids of the protein calreticulin) were detected and found always to generate frameshift mutations. All detected mutant calreticulin proteins shared a novel amino acid sequence at the C-terminal. Mutations in CALR are acquired early in the clonal history of the disease, and they cause activation of JAK/STAT signaling. The CALR mutations are the second most frequent mutations in Ph(-) MPN patients after the JAK2V617F mutation, and their detection has significantly improved the diagnostic approach for ET and PMF. The characteristics of the CALR mutations as well as their diagnostic, clinical, and pathogenesis implications are discussed in this review.
...
PMID:Calreticulin mutations in myeloproliferative neoplasms. 2538 51

The discovery of the JAK2V617F mutation followed by the discovery of other genetic abnormalities allowed important progress in the understanding of the pathogenesis and management of myeloproliferative neoplasms (MPN)s. Classical Breakpoint cluster region-Abelson (BCR-ABL)-negative neoplasms include 3 main disorders: essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). Genomic studies have shown that these disorders are more heterogeneous than previously thought with 3 main entities corresponding to different gene mutations: the JAK2 disorder, essentially due to JAK2V617F mutation, which includes nearly all PVs and a majority of ETs and PMFs with a continuum between these diseases and the myeloproliferative leukemia (MPL) and calreticulin (CALR) disorders, which include a fraction of ET and PMF. All of these mutations lead to a JAK2 constitutive activation. Murine models either with JAK2V617F or MPLW515L, but also with JAK2 or MPL germ line mutations found in hereditary thrombocytosis, have demonstrated that they are drivers of myeloproliferation. However, the myeloproliferative driver mutation is still unknown in approximately 15% of ET and PMF, but appears to also target the JAK/Signal Transducer and Activator of Transcription (STAT) pathway. However, other mutations in genes involved in epigenetics or splicing also can be present and can predate or follow mutations in signaling. They are involved either in clonal dominance or in phenotypic changes, more particularly in PMF. They can be associated with leukemic progression and might have an important prognostic value such as additional sex comb-like 1 mutations. Despite this heterogeneity, it is tempting to target JAK2 and its signaling for therapy. However in PMF, Adenosine Tri-Phosphate (ATP)-competitive JAK2 inhibitors have shown their interest, but also their important limitations. Thus, other approaches are required, which are discussed in this review.
...
PMID:Myeloproliferative neoplasms: JAK2 signaling pathway as a central target for therapy. 2548 52

According to the 2008 revision of the World Health Organization (WHO) classification of myeloid malignancies, philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs) include clonal, hematologic disorders such as polycythemia vera, primary myelofibrosis, and essential thrombocythemia.Recent years have witnessed major advances in the understanding of the molecular pathophysiology of these rare subgroups of chronic, myeloproliferative disorders. Identification of somatic mutations in genes associated with pathogenesis and evolution of these myeloproliferative conditions (Janus Kinase 2; myeloproliferative leukemia virus gene; calreticulin) led to substantial changes in the international guidelines for diagnosis and treatment of Ph-negative MPN during the last few years.The MPN-Working Group (MPN-WG), a panel of hematologists with expertise in MPN diagnosis and treatment from various parts of India, examined applicability of this latest clinical and scientific evidence in the context of hematology practice in India.This manuscript summarizes the consensus recommendations formulated by the MPN-WG that can be followed as a guideline for management of patients with Ph-negative MPN in the context of clinical practice in India.
...
PMID:Myeloproliferative neoplasms working group consensus recommendations for diagnosis and management of primary myelofibrosis, polycythemia vera, and essential thrombocythemia. 2581 May 69

Polycythaemia vera, essential thrombocytosis and primary myelofibrosis are closely related, clonal myeloproliferative neoplasms. Our knowledge of the underlying molecular mechanisms driving these diseases has increased dramatically during the latest ten years. Traditionally, treatment of these malignancies has focused on lowering their inherent thromboembolic risk but with the discovery of the JAK2-V617F mutation and most recently the calreticulin mutations new therapeutic options such as interferon-alpha, JAK2-inhibitors and statins are being contemplated. This article reviews these new treatment options.
...
PMID:[Status and perspectives on chronic myeloproliferative neoplasm treatment]. 2596 90

In this study, our goal was to evaluate whether the expressions of microRNA (miR)-150, miR-146b, miR-31 and miR-95 demonstrate primary myelofibrosis (PMF) specificity, associations with fibrosis grade, hematologic phenotypes, or myeloproliferative neoplasm (MPN)-associated mutations. A total of 51 formalin-fixed and paraffin-embedded bone marrow MPN samples, including 15 polycythemia vera (PV), 26 essential thrombocythemia (ET), and 10 PMF, and 24 normal controls were included. The expression of microRNA (miRNA) was detected by quantitative real-time polymerase chain reaction using miRNA specific primers. RNU6-2 was analyzed for all samples as endogenous control for relative quantification. Information for fibrosis, hematologic parameters, Janus kinase 2 (JAK2) V617F, and calreticulin (CALR) mutations was obtained from medical records. Significant increment of miR-146b was detected in PMF compared to normal controls (P=0.008). Moreover, expression of miR-146b tended to increase according to increment of fibrosis grade, and patients with myelofibrosis (MF) grade 3 showed significantly higher expression than patients with MF 0 to 2 (P=0.022, 0.001 and 0.013, respectively) or normal controls (P<0.001). The expression of miR-31 also showed tendency to increase following fibrosis and miR-150 showed up-regulated expression in ET (P=0.015) compared to normal control. There was no relationship between miRNA expression and hematologic indices except miR-95 showed negative correlation with platelet count (P=0.024). There was no significant correlation between miRNA expression and JAK2 V617F or CALR mutation. Up-regulation of miR-146b could be used as a fibrosis-indicating marker and might be helpful in the study of fibrotic mechanism in MPN, as well as other fibrotic diseases.
...
PMID:Up-regulation of MicroRNA 146b is Associated with Myelofibrosis in Myeloproliferative Neoplasms. 2611 95


1 2 3 4 Next >>