polycythaemia vera
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2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Jaymi Tan ◽  
Yock Ping Chow ◽  
Norziha Zainul Abidin ◽  
Kian Meng Chang ◽  
Veena Selvaratnam ◽  
...  

Abstract Background The Philadelphia (Ph)-negative myeloproliferative neoplasms (MPNs), namely essential thrombocythaemia (ET), polycythaemia vera (PV) and primary myelofibrosis (PMF), are a group of chronic clonal haematopoietic disorders that have the propensity to advance into bone marrow failure or acute myeloid leukaemia; often resulting in fatality. Although driver mutations have been identified in these MPNs, subtype-specific markers of the disease have yet to be discovered. Next-generation sequencing (NGS) technology can potentially improve the clinical management of MPNs by allowing for the simultaneous screening of many disease-associated genes. Methods The performance of a custom, in-house designed 22-gene NGS panel was technically validated using reference standards across two independent replicate runs. The panel was subsequently used to screen a total of 10 clinical MPN samples (ET n = 3, PV n = 3, PMF n = 4). The resulting NGS data was then analysed via a bioinformatics pipeline. Results The custom NGS panel had a detection limit of 1% variant allele frequency (VAF). A total of 20 unique variants with VAFs above 5% (4 of which were putatively novel variants with potential biological significance) and one pathogenic variant with a VAF of between 1 and 5% were identified across all of the clinical MPN samples. All single nucleotide variants with VAFs ≥ 15% were confirmed via Sanger sequencing. Conclusions The high fidelity of the NGS analysis and the identification of known and novel variants in this study cohort support its potential clinical utility in the management of MPNs. However, further optimisation is needed to avoid false negatives in regions with low sequencing coverage, especially for the detection of driver mutations in MPL.


Hemato ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 769-780
Author(s):  
Uzma Faruqi ◽  
Karen A. Breen

Philadelphia chromosome negative myeloproliferative neoplasms (MPN) are clonal haematopoietic stem cell disorders. Of the MPNs, polycythaemia vera (PV) and essential thrombocythaemia (ET) confer a high thrombotic risk which may be the presenting feature of the disease. Thrombotic complications consist of both arterial and venous events and the presence of the JAK2 V617F mutation is associated with higher risk. Patients presenting with an unprovoked thrombus, particularly at an unusual site, e.g., splanchnic circulation, should be screened for the presence of this mutation. Historically, warfarin has been the only option for oral anticoagulation; however, there is now increasing evidence and practise to use direct oral anticoagulants (DOACs) in cancer. The seminal randomised control trials have demonstrated non-inferiority compared to low molecular weight heparin (LMWH) with a preferable bleeding profile. DOACs are now the first line treatment for atrial fibrillation and venous thromboembolic disease, as recommended by NICE, and therefore there is increasing familiarity with these agents. Furthermore, there are now targeted antidotes available. This paper reviews evidence for efficacy and safety of DOACs in MPN. Whilst no randomised control trials have been performed, several retrospective studies and reviews of registry data have reproducibly demonstrated that, alongside cytoreduction, DOACs represent an effective modality of anticoagulation for treatment of venous thromboembolism in MPN. Furthermore, dosing regimens provide the option for longer term secondary prophylaxis. Use of DOACs in arterial thrombosis is an area for future development and there is already some evidence for utility in peripheral vascular disease.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chartsiam Tipgomut ◽  
Archrob Khuhapinant ◽  
Marieangela C. Wilson ◽  
Saiphon Poldee ◽  
Kate J. Heesom ◽  
...  

AbstractPolycythaemia vera (PV) is a haematological disorder caused by an overproduction of erythroid cells. To date, the molecular mechanisms involved in the disease pathogenesis are still ambiguous. This study aims to identify aberrantly expressed proteins in erythroblasts of PV patients by utilizing mass spectrometry-based proteomic analysis. Haematopoietic stem cells (HSCs) were isolated from newly-diagnosed PV patients, PV patients who have received cytoreductive therapy, and healthy subjects. In vitro erythroblast expansion confirmed that the isolated HSCs recapitulated the disease phenotype as the number of erythroblasts from newly-diagnosed PV patients was significantly higher than those from the other groups. Proteomic comparison revealed 17 proteins that were differentially expressed in the erythroblasts from the newly-diagnosed PV patients compared to those from healthy subjects, but which were restored to normal levels in the patients who had received cytoreductive therapy. One of these proteins was S-methyl-5′-thioadenosine phosphorylase (MTAP), which had reduced expression in PV patients’ erythroblasts. Furthermore, MTAP knockdown in normal erythroblasts was shown to enhance their proliferative capacity. Together, this study identifies differentially expressed proteins in erythroblasts of healthy subjects and those of PV patients, indicating that an alteration of protein expression in erythroblasts may be crucial to the pathology of PV.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4620-4620
Author(s):  
Kushani Ediriwickrema ◽  
Andrew J Wilson ◽  
Jenny O'Nions ◽  
Mallika Sekhar ◽  
Syeda Ahmed ◽  
...  

Abstract Introduction The molecular categorisation of myeloproliferative neoplasms (MPNs) has changed the landscape of diagnosis and treatment. Polycythaemia vera (PV) is characterised by red blood cell proliferation and JAK2 V617F or Exon 12 mutations in up to 98% of patients 1. However, some patients without such mutations have an arduous diagnostic course with varying management and prognostic outcomes 2. We present our experience in managing this challenging cohort and aim to illuminate a potential diagnostic pathway for patients. Method We searched electronic records of patients attending haematology clinics over the last 20 years at University College Hospital with a prior diagnosis of PV / erythrocytosis (presenting with raised Haemoglobin (Hb) &/ Haematocrit (Hct)) with no evidence of JAK2 exon 12 or 14 mutations on bone marrow or peripheral blood molecular analysis (multiplex PCR sensitivity 0.1%). We reviewed their diagnostic workup, which included full blood count & where available, bone marrow myeloid (Illumina TruSight Myeloid) & erythroid next generation sequencing (NGS) panels. Results 37 patients with JAK2 V617F & Exon 12 mutation negative erythrocytosis were identified. Patients were categorised in to 3 groups 2; idiopathic erythrocytosis (IE), secondary polycythaemia (SP) & high affinity haemoglobinopathies (HAH); patient characteristics are summarised in Table 1. The median age of IE & HAH was younger, their presenting Hb/Hct levels was higher compared to SP, with a male predominance. Constitutional symptoms were only reported in the IE cohort. Erythropoietin (EPO) was elevated in HAH & IE patients but within normal range in SP. Thrombotic events occurred in all cohorts, most frequently in IE. Splenomegaly was reported in 4/21 IE, 1/13 SP, but was not a feature in HAH patients. When performed, IE red cell mass (RCM) studies were raised but within normal range in SP patients. Table 2 details IE cohort erythroid mutations. Myeloid NGS only identified MPL and BCOR mutations of pathogenic significance and multiple single nucleotide polymorphisms of no known significance. No abnormalities were demonstrated in 15% of SP patients that underwent bone marrow myeloid mutational analysis. Venesections (VS) were instigated in 95% of the IE cohort, antiplatelets (AP) in 52%, anticoagulation (AC) in 14% and cytoreductive therapy (CT) in 19% due to intolerance/failure of VS. VS programme was instigated in 46% of SP patients, AP in 7% and AC in 47%. Discussion The median age of our IE cohort was 48 yrs with a 19% incidence of thrombosis. Where performed, bone marrow histology demonstrated hypercellularity but was not consistent with MPN diagnostic criteria. Myeloid NGS panel mutations such as BCOR may represent clonal haematopoieis of indeterminate potential. Heterozygous VHL C598T & C376A mutations, in keeping with Chuvash polycythaemia, were demonstrated. Mutations in EGLN1 & BPGM,were detected in our patients, however there was an absence of correlating haematological parameters or family history to support a diagnosis of congenital erythrocytosis (2). Variants of unknown significance were also detected in SH2B3, BMP6 & EGLN3 gene duplication. SP patients were older (median age 68 years) and where performed had normal RCM and no myeloid mutations identified. The initial approach adopted at our centre for diagnosing and managing JAK2 V617F & Exon 12 negative erythocytosis begins with clinical evaluation for secondary causes. This is followed by assessment of EPO level, RCM study, extended molecular mutational analysis involving screening for high affinity haemoglobins, congenital erythrocytosis and bone marrow histology. Where patients are symptomatic or considered at high risk for thrombosis, we venesect to a personalised target and patients are offered AP and/or AC. CT is instigated where VS is not tolerated or ineffective, however this approach is not corroborated in the literature. Our experience highlights the clinical heterogeneity of JAK2 negative erythrocytosis and the need to develop a robust and systematic diagnostic and treatment algorithm with further clarification of the role of molecular profiling. 1. William W, Kralovics R. Genetic basis and molecular pathophysiology of classical myeloproliferative neoplasms. Blood. 2017 Feb; 129(6):667-679 2. McMullin MF. Idiopathic erythrocytosis: a disappearing entity. Hematology Am Soc Educ Program. 2009; 2009(1):629-635 Figure 1 Figure 1. Disclosures Sekhar: Novartis: Consultancy, Research Funding.


2021 ◽  
Vol 11 ◽  
Author(s):  
Fiona M. Healy ◽  
Lekh N. Dahal ◽  
Jack R.E. Jones ◽  
Yngvar Floisand ◽  
John F. Woolley

Myeloid malignancies are a heterogeneous group of clonal haematopoietic disorders, caused by abnormalities in haematopoietic stem cells (HSCs) and myeloid progenitor cells that originate in the bone marrow niche. Each of these disorders are unique and present their own challenges with regards to treatment. Acute myeloid leukaemia (AML) is considered the most aggressive myeloid malignancy, only potentially curable with intensive cytotoxic chemotherapy with or without allogeneic haematopoietic stem cell transplantation. In comparison, patients diagnosed with chronic myeloid leukaemia (CML) and treated with tyrosine kinase inhibitors (TKIs) have a high rate of long-term survival. However, drug resistance and relapse are major issues in both these diseases. A growing body of evidence suggests that Interferons (IFNs) may be a useful therapy for myeloid malignancies, particularly in circumstances where patients are resistant to existing front-line therapies and have risk of relapse following haematopoietic stem cell transplant. IFNs are a major class of cytokines which are known to play an integral role in the non-specific immune response. IFN therapy has potential as a combination therapy in AML patients to reduce the impact of minimal residual disease on relapse. Alongside this, IFNs can potentially sensitize leukaemic cells to TKIs in resistant CML patients. There is evidence also that IFNs have a therapeutic role in myeloproliferative neoplasms (MPNs) such as polycythaemia vera (PV) and primary myelofibrosis (PMF), where they can restore polyclonality in patients. Novel formulations have improved the clinical effectiveness of IFNs. Low dose pegylated IFN formulations improve pharmacokinetics and improve patient tolerance to therapies, thereby minimizing the risk of haematological toxicities. Herein, we will discuss recent developments and the current understanding of the molecular and clinical implications of Type I IFNs for the treatment of myeloid malignancies.


2021 ◽  
Vol 84/117 (4) ◽  
Author(s):  
Ertan Karacay ◽  
Utku Cenikli ◽  
Ahmet Özsimsek ◽  
Irem Atalay Karacay ◽  
Yavuz Yüksel ◽  
...  

2021 ◽  
Author(s):  
Jaymi Tan ◽  
Yock Ping Chow ◽  
Norziha Zainul Abidin ◽  
Kian Meng Chang ◽  
Veena Selvaratnam ◽  
...  

Abstract Background The Philadelphia (Ph)-negative myeloproliferative neoplasms (MPNs) (i.e. essential thrombocythaemia (ET), polycythaemia vera (PV), and primary myelofibrosis (PMF)) are a group of chronic clonal haematopoietic disorders that have the propensity to advance into bone marrow failure or acute myeloid leukaemia; often resulting in fatality. Although driver mutations have been identified in these Ph-negative MPNs, subtype-specific markers of the disease have yet to be discovered. Next-generation sequencing (NGS) technology can potentially improve the clinical management of Ph-negative MPNs by allowing for the simultaneous screening of many disease-associated genes. Methods The performance of a custom, in-house designed 22-gene NGS panel was technically validated using reference standards across two independent replicate runs. The panel was subsequently used to screen a total of 10 clinical MPN samples (ET n = 3, PV n = 3, PMF n = 4). The resulting NGS data was then analysed via a bioinformatics pipeline. Results The custom NGS panel had a detection limit of 1% variant allele frequency (VAF). A total of 44 variants with minor allele frequencies (MAFs) of ≥ 1%, and 20 variants with MAFs of < 1% were identified (4 of which were putatively novel variants with potential biological significance) across the 10 MPN samples. All single nucleotide variants with VAFs ≥ 15% were confirmed via Sanger sequencing. Conclusions The high fidelity of the NGS analysis and the identification of known and novel variants support its potential clinical utility in the management of Ph-negative MPNs.


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