scholarly journals Recent advances in understanding myelofibrosis and essential thrombocythemia

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 700 ◽  
Author(s):  
William Vainchenker ◽  
Stefan N. Constantinescu ◽  
Isabelle Plo
Keyword(s):  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Great Majority ◽  
Primary Myelofibrosis ◽  
Driver Mutations ◽  
New Therapeutic Approaches ◽  
Recent Advances ◽  
Downstream Effectors ◽  
Thrombopoietin Receptor

The classicBCR-ABL-negative myeloproliferative neoplasms (MPNs), a form of chronic malignant hemopathies, have been classified into polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). ET and PMF are two similar disorders in their pathogenesis, which is marked by a key role of the megakaryocyte (MK) lineage. Whereas ET is characterized by MK proliferation, PMF is also associated with aberrant MK differentiation (myelodysplasia), leading to the release of cytokines in the marrow environment, which causes the development of myelofibrosis. Thus, PMF is associated with both myeloproliferation and different levels of myelodysplastic features. MPNs are mostly driven by mutated genes called MPN drivers, which abnormally activate the cytokine receptor/JAK2 pathway and their downstream effectors. The recent discovery ofCALRmutations has closed a gap in our knowledge and has shown that this mutated endoplasmic reticulum chaperone activates the thrombopoietin receptor MPL and JAK2. These genetic studies have shown that there are two main types of MPNs: JAK2V617F-MPNs, including ET, PV, and PMF, and the MPL-/CALR-MPNs, which include only ET and PMF. These MPN driver mutations are associated with additional mutations in genes involved in epigenetics, splicing, and signaling, which can precede or follow the acquisition of MPN driver mutations. They are involved in clonal expansion or phenotypic changes or both, leading to myelofibrosis or leukemic transformation or both. Only a few patients with ET exhibit mutations in non-MPN drivers, whereas the great majority of patients with PMF harbor one or several mutations in these genes. However, the entire pathogenesis of ET and PMF may also depend on other factors, such as the patient’s constitutional genetics, the bone marrow microenvironment, the inflammatory response, and age. Recent advances allowed a better stratification of these diseases and new therapeutic approaches with the development of JAK2 inhibitors.

New Advances in the Pathogenesis and Therapy of Essential Thrombocythemia

Hematology ◽  
2008 ◽  
Vol 2008 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Ross L. Levine ◽  
Mark Heaney
Keyword(s):  
Essential Thrombocythemia ◽  
Myeloid Leukemia ◽  
Significant Proportion ◽  
Myeloproliferative Neoplasm ◽  
Primary Myelofibrosis ◽  
Clinical Syndrome ◽  
Activating Mutations ◽  
Thrombopoietin Receptor ◽  
Increased Risk

Abstract Essential thrombocythemia (ET) is a hematopoietic disorder that manifests clinically as thrombocytosis, and patients with ET are at increased risk for developing thrombosis, myelofibrosis, and transformation to acute myeloid leukemia. Although ET was recognized as a distinct clinical syndrome more than 6 decades ago and was classified as a myeloproliferative neoplasm (MPN) by William Dameshek in 1951, the molecular pathogenesis of ET remained unknown until 2005, when activating mutations in the JAK2 tyrosine kinase (JAK2V617F) were identified in a significant proportion of patients with ET, polycythemia vera (PV) and primary myelofibrosis (PMF). In addition, subsequent studies have identified gain-of-function mutations in the thrombopoietin receptor (MPL) in a subset of patients with JAK2V617F-negative ET, suggesting that JAK2 activation by distinct mechanisms contributes to the pathogenesis of ET. Despite these important observations, important questions remain regarding the role of JAK2/MPL mutations in ET pathogenesis, the etiology of JAK2/MPL negative ET, the factors that distinguish ET from other MPNs with the JAK2V617F mutation, and the role of JAK2-targeted therapies for the treatment of these MPNs.

scholarly journals The role of JAK2 inhibitors in MPNs 7 years after approval

Blood ◽  
2018 ◽  
Vol 131 (22) ◽  
pp. 2426-2435 ◽  
Author(s):  
Francesco Passamonti ◽  
Margherita Maffioli
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Symptom Relief ◽  
Primary Myelofibrosis ◽  
Driver Mutations ◽  
Volume Response ◽  
Symptom Response ◽  
Definition Of ◽  
Jak2 Inhibitors

Abstract Myeloproliferative neoplasms (MPNs) include essential thrombocythemia, polycythemia vera (PV), and primary myelofibrosis (MF). Phenotype-driver mutations of JAK2, CALR, and MPL genes are present in MPNs and can be variably combined with additional mutations. Driver mutations entail a constitutive activation of the JAK2/STAT pathway, the key signaling cascade in MPNs. Among JAK2 inhibitors (JAKis), ruxolitinib (RUX) has been approved for the treatment of intermediate and high-risk MF and for PV inadequately controlled by or intolerant of hydroxyurea. Other JAKis, such as fedratinib and pacritinib, proved to be useful in MF. The primary end points in MF trials were spleen volume response (SVR) and symptom response, whereas in PV trials they were hematocrit control with or without spleen response. In advanced MF, RUX achieved a long lasting SVR of >35% in ∼60% of patients, establishing a new benchmark for MF treatment. RUX efficacy in early MF is also remarkable and toxicity is mild. In PV, RUX achieved hematocrit control in ∼60% of cases and SVR in 40%. Symptom relief was evident in both conditions. In the long-term, however, many MF patients lose their SVR. Indeed, the definition of RUX failure and the design of new trials in this setting are unmet needs. Decrease of hemoglobin/platelet levels and increased infection rates are the most common side effects of RUX, and nonmelanoma skin tumors need to be monitored while on treatment. In conclusion, the introduction of JAKis raises the bar of treatment goals in MF and PV.

From Janus kinase 2 to calreticulin: the clinically relevant genomic landscape of myeloproliferative neoplasms

Blood ◽  
2014 ◽  
Vol 123 (24) ◽  
pp. 3714-3719 ◽  
Author(s):  
Mario Cazzola ◽  
Robert Kralovics
Keyword(s):  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Janus Kinase ◽  
Driver Mutations ◽  
Mutation Status ◽  
Genomic Landscape ◽  
Exon 10 ◽  
Stat Pathway

Abstract 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.

scholarly journals Experimental Modeling of Myeloproliferative Neoplasms

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 813 ◽  
Author(s):  
Lucie Lanikova ◽  
Olga Babosova ◽  
Josef T. Prchal
Keyword(s):  
Myeloproliferative Neoplasms ◽  
Drug Efficacy ◽  
Primary Myelofibrosis ◽  
Driver Mutations ◽  
Essential Thrombocytosis ◽  
Oncogenic Signaling ◽  
Novel Technologies ◽  
Genetic Landscape ◽  
Induced Pluripotent

Myeloproliferative neoplasms (MPN) are genetically very complex and heterogeneous diseases in which the acquisition of a somatic driver mutation triggers three main myeloid cytokine receptors, and phenotypically expresses as polycythemia vera (PV), essential thrombocytosis (ET), and primary myelofibrosis (PMF). The course of the diseases may be influenced by germline predispositions, modifying mutations, their order of acquisition and environmental factors such as aging and inflammation. Deciphering these contributory elements, their mutual interrelationships, and their contribution to MPN pathogenesis brings important insights into the diseases. Animal models (mainly mouse and zebrafish) have already significantly contributed to understanding the role of several acquired and germline mutations in MPN oncogenic signaling. Novel technologies such as induced pluripotent stem cells (iPSCs) and precise genome editing (using CRISPR/Cas9) contribute to the emerging understanding of MPN pathogenesis and clonal architecture, and form a convenient platform for evaluating drug efficacy. In this overview, the genetic landscape of MPN is briefly described, with an attempt to cover the main discoveries of the last 15 years. Mouse and zebrafish models of the driver mutations are discussed and followed by a review of recent progress in modeling MPN with patient-derived iPSCs and CRISPR/Cas9 gene editing.

scholarly journals The Presence of ASXL1 Mutations As Well As a Total Number of Myeloid Driver Mutations Higher Than Two Is Strongly Associated with the Diagnosis of Primary Myelofibrosis As Opposed to Essential Thrombocythemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4595-4595
Author(s):  
Paulo Vidal Campregher ◽  
Ricardo Helman ◽  
Welbert Oliveira Pereira ◽  
Renato D Puga ◽  
Bianca Lisboa ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Essential Thrombocythemia ◽  
Triple Negative ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
Driver Mutations ◽  
Genetic Abnormality ◽  
Myeloid Malignancies ◽  
Whole Exome ◽  
Washington University

Abstract Introduction: Primary Myelofibrosis (PMF) and Essential Thrombocythemia (ET) are myeloproliferative neoplasms with similar genetic backgrounds. Both diseases are characterized, at the molecular level, by mutations in the genes JAK2, MPL and CALR. In addition recurring mutations is several other genes have been described in myeloid malignancies in general. Although the differential diagnosis between PMF and ET may be straight forward in most cases, there is a significant clinical and pathologic overlap between these two conditions, making the differential diagnosis difficult sometimes, mostly between early PMF and ET. With the goal of utilizing genomic information to better differentiate ET from PMF we decided to identify and compare all genomic alterations present in patients with ET and PMF, through whole exome / genome sequencing of paired granulocytes and skin. Methods: A total of 84 patients with either PMF (N=48) or ET (N=36) were analyzed. DNA was extracted from CD66b+ magnetic bead selected granulocytes (EasySep, Stem Cell Technologies) and matched skin biopsies with QiaAmp DNA Mini kit (Qiagen). Whole-exome targeted capture was carried out on 3 μg of genomic DNA, using the SureSelect Human Exome Kit 51Mb version 4 (Agilent Technologies, Inc., Santa Clara, CA, USA). The exome library was sequenced with 100 bp paired-end reads on an Illumina HiSeq2000. Somatic variants calls were generated by combining the output of Somatic Sniper (Washington University), Mutect (Broad Institute) and Pindel (Washington University). Tumor coverage was 150x and germline was 60x. The combined output of these 3 softwares was further filtered by in-house criteria in order to reduce false-positive calls (minimum coverage at both tumor/germline ≥8 reads; fraction of reads supporting alternate allele ≥5% in tumor and ≤10% in germline; ratio of allele fraction tumor:germline >2). All JAK2 and CALR mutations were validated through Sanger sequencing. Validations of other somatic mutations are under way at this point. For this work, other myeloid driver mutations were defined as mutations occurring recurrently in myeloid malignancies in the medical literature, and in this cohort of patients these mutations were present in the following genes: ASXL1, ATM, CALR, CBL, CUX1, DNMT3A, EZH2, GATA2, GNAS, IDH1, IDH2, JAK2, MPL, NRAS, SH2B3, SF3B1, STAG2, TET2, NFE2, SMC3, SUZ12, PRPF8, SRSF2, U2AF1, TP53. Fisherxs exact test was used for statistical comparisons. Results: The most common mutated genes after JAK2 and CALR were ASXL1 (n=16), TET2 (n=9) and DNMT3A (n=9). After data analysis, the patients could be divided in 7 groups based on the genomic profile: A – JAK2 mutation as the single genetic abnormality (JAK2_Single) (N=24), B – JAK2 plus other myeloid driver mutations (JAK2_Plus) (N=25), C - CALR mutation as the single genetic abnormality (CALR_Single) (N=11), D – CALR plus other myeloid driver mutations (CALR_Plus) (N=9), E – MPL mutation (N=1), F – Triple negative without other myeloid driver mutations (TN_Single) (N=8), G – No JAK2, CALR or MPL (triple negative) but with other myeloid driver mutations (TN_plus) (N=6) 1 – The presence of 3 or more total myeloid driver mutations was strongly associated with a diagnosis of PMF Table 1mut<3mut>2TE282PMF2521 P= 0.0002 2 – The presence of ASXL1 mutations was strongly associated with a diagnosis of PMF Table 2ASXL1+ASXL1-TE135PMF1533 P=0.0007 In order to validate our findings in an independent cohort of patients, we performed the same analysis using data from 2 published studies that evaluated myeloid multi-gene panels in ET and PMF (Nangalia J, NEJM 2013) (Lundberg P, Blood, 2014). We pooled together all patients with ET (N=117) and PMF (N=56) from both studies and repeated the two previous analyses, that confirmed the previous results: Table 3mut<3mut>2TE1106PMF4214P=0.0005ASXL1+ASXL1-TE4113PMF1442P=3.9E-05 Conclusions: We have demonstrated that ASXL1 mutations as well as a number of myeloid driver mutations higher than two is strongly associated with PMF. This information may be useful in the near future to improve the differential diagnosis between ET and PMF. Disclosures No relevant conflicts of interest to declare.

scholarly journals Update from the latest WHO classification of MPNs: a user’s manual

Hematology ◽  
2016 ◽  
Vol 2016 (1) ◽  
pp. 534-542 ◽  
Author(s):  
Francesco Passamonti ◽  
Margherita Maffioli
Keyword(s):  
Diagnostic Criteria ◽  
Who Classification ◽  
Triple Negative ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
World Health ◽  
Driver Mutations ◽  
Health Organization

Abstract The 2016 multiparameter World Health Organization (WHO) classification for Philadelphia-negative myeloproliferative neoplasms (MPNs) integrates clinical features, morphology, and genetic data to diagnose polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The main novelties are: (1) the reduction of the hemoglobin (Hb) level threshold to diagnose PV, now established at 16.5 g/dL for men and 16 g/dL for women (based on the identification of MPN patients with PV-consistent bone marrow [BM] features and a Hb level lower than that established in the 2008 WHO classification for PV); (2) the recognition of prefibrotic/early PMF, distinguishable from ET on the basis of BM morphology, an entity having a higher tendency to develop overt myelofibrosis or acute leukemia, and characterized by inferior survival; (3) the central role of BM morphology in the diagnosis of ET, prefibrotic/early PMF, PMF, and PV with borderline Hb values; megakaryocyte number and morphology (typical in ET, atypical in both PMF forms) accompanied by a new distinction of reticulin fibrosis grade in PMF (grade 1 in prefibrotic/early PMF and grade 2-3 in PMF) constitute diagnostic criteria; and (4) the inclusion of all mutually exclusive MPN driver mutations (JAK2, CALR, and MPL) as major diagnostic criteria in ET and PMF; 10% to 15% of these patients are triple negative, and in these cases the search for an additional clonal marker (eg, mutations in ASXL1, EZH2, TET2, IDH1/IDH2, SRSF2, and SF3B1) is warranted.

scholarly journals What are the current treatment approaches for patients with polycythemia vera and essential thrombocythemia?

Hematology ◽  
2017 ◽  
Vol 2017 (1) ◽  
pp. 480-488 ◽  
Author(s):  
Alessandro M. Vannucchi ◽  
Paola Guglielmelli
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
State Of The Art ◽  
Myeloproliferative Neoplasms ◽  
Symptom Burden ◽  
Current Treatment ◽  
Interferon Α ◽  
Jak2 Inhibitor ◽  
Chronic Myeloproliferative Neoplasms

Abstract Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms that are characterized by thrombohemorrhagic complications, symptom burden, and impaired survival mainly due to thrombosis, progression to myelofibrosis, and transformation to acute leukemia. In this manuscript, we will review the most recent changes in diagnostic criteria, the improvements in risk stratification, and the “state of the art” in the daily management of these disorders. The role of conventional therapies and novel agents, interferon α and the JAK2 inhibitor ruxolitinib, is critically discussed based on the results of a few basic randomized clinical studies. Several unmet needs remain, above all, the lack of a curative approach that might overcome the still burdensome morbidity and mortality of these hematologic neoplasms, as well as the toxicities associated with therapeutic agents.

scholarly journals Survival and Disease Progression in Essential Thrombocythemia Are Significantly Influenced by Accurate Morphologic Diagnosis: An International Study

2011 ◽  
Vol 29 (23) ◽  
pp. 3179-3184 ◽  
Author(s):  
Tiziano Barbui ◽  
Juergen Thiele ◽  
Francesco Passamonti ◽  
Elisa Rumi ◽  
Emanuela Boveri ◽  
...  
Keyword(s):  
Essential Thrombocythemia ◽  
Clinical Relevance ◽  
Myeloproliferative Neoplasms ◽  
Survival Rates ◽  
Multivariable Analysis ◽  
Primary Myelofibrosis ◽  
Incidence Rates ◽  
Complication Rates ◽  
Eligibility Criteria ◽  
Strict Adherence

PurposeThe WHO diagnostic criteria underscore the role of bone marrow (BM) morphology in distinguishing essential thrombocythemia (ET) from early/prefibrotic primary myelofibrosis (PMF). This study examined the clinical relevance of such a distinction.MethodsRepresentatives from seven international centers of excellence for myeloproliferative neoplasms convened to create a clinicopathologic database of patients previously diagnosed as having ET (N = 1,104). Study eligibility criteria included availability of treatment-naive BM specimens obtained within 1 year of diagnosis. All bone marrows subsequently underwent a central re-review.ResultsDiagnosis was confirmed as ET in 891 patients (81%) and was revised to early/prefibrotic PMF in 180 (16%); 33 patients were not evaluable. In early/prefibrotic PMF compared with ET, the 10-year survival rates (76% and 89%, respectively) and 15-year survival rates (59% and 80%, respectively), leukemic transformation rates at 10 years (5.8% and 0.7%, respectively) and 15 years (11.7% and 2.1%, respectively), and rates of progression to overt myelofibrosis at 10 years (12.3% and 0.8%, respectively) and 15 years (16.9% and 9.3%) were significantly worse. The respective death, leukemia, and overt myelofibrosis incidence rates per 100 patient-years for early/prefibrotic PMF compared with ET were 2.7% and 1.3% (relative risk [RR], 2.1; P < .001), 0.6% and 0.1% (RR, 5.2; P = .001), and 1% and 0.5% (RR, 2.0; P = .04). Multivariable analysis confirmed these findings and also identified age older than 60 years (hazard ratio [HR], 6.7), leukocyte count greater than 11 × 109/L (HR, 2.01), anemia (HR, 2.95), and thrombosis history (HR, 2.81) as additional risk factors for survival. Thrombosis and JAK2V617F incidence rates were similar between the two groups. Survival in ET was similar to the sex- and age-standardized European population.ConclusionThis study validates the clinical relevance of strict adherence to WHO criteria in the diagnosis of ET and provides important information on survival, disease complication rates, and prognostic factors in strictly WHO-defined ET and early/prefibrotic PMF.

Evaluation of the JAK2 V617F gene mutation in myeloproliferative neoplasms cases: a one-center study from Eastern Anatolia

2019 ◽  
Vol 44 (4) ◽  
pp. 492-498
Author(s):  
Gonca Gulbay ◽  
Elif Yesilada ◽  
Mehmet Ali Erkurt ◽  
Harika Gozukara Bag ◽  
Irfan Kuku ◽  
...  
Keyword(s):  
Blood Cell ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Hematological Parameters ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Myeloproliferative Disorders ◽  
Jak2 V617f Mutation ◽  
V617f Mutation ◽  
The Difference

AbstractObjectiveDetection ofJAK2V617F in myeloproliferative neoplasms (MPNs) is very important in both diagnosis and disease progression. In our study, we investigated the frequency ofJAK2V617F mutation in patients with myeloproliferative disorders.MethodsWe retrospectively reviewed the records of 720 patients (174 females and 546 males) who were tested for JAK2 V617F mutation from January 2007 to December 2017.ResultsIn our patients were determined 22.6%JAK2V617F mutation. 33.3% in women, 19.2% in men have been positive forJAK2V617F mutation. In our studyJAK2V617F present in 48.6% of essential thrombocythemia, 80.5% of polycythemia rubra vera (PV), 47.5% of primary myelofibrosis, 10% of MPNs, unclassifiable, 0.8% of others. We also investigated the difference in hematological parameters [white blood cell, hemoglobin (Hb), hematocrit (HCT), red blood cell distribution widths (RDW) and platelets count (PLT)] betweenJAK2V617F positive andJAK2V617F negative patients.ConclusionsInvestigation of the JAK2 V617F mutation is very important in cases of MPNs. In our study JAK2 V617F mutation was higher in PV, essential thrombocythemia, and primary myelofibrosis patients. However, there were significant differences in Hb, HCT, RDW and PLT levels in mutation-positive patients.

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