scholarly journals A Rare Case of Triple-Negative Essential Thrombocythemia in a Young Postsplenectomy Patient: A Diagnostic Challenge

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Tugce Akcan ◽  
Paolo Strati ◽  
Melissa Yan ◽  
Modupe Idowu
Keyword(s):  
Bone Marrow ◽  
Essential Thrombocythemia ◽  
Triple Negative ◽  
Myeloproliferative Neoplasms ◽  
Splenic Vein ◽  
Myeloproliferative Neoplasm ◽  
Diagnostic Challenge ◽  
Reactive Thrombocytosis ◽  
Vein Thrombosis ◽  
Bone Marrow Histology

The distinction between primary and reactive thrombocytosis by bone marrow histology is very important. Reactive thrombocytosis, the most common cause of thrombocytosis, can be expected in postsplenectomy states; however, close hematological evaluation of prolonged thrombocytosis is essential to identify patients who may have an underlying myeloproliferative neoplasm. We report a 37-year-old woman who was found to have portal, mesenteric, and splenic vein thrombosis with thrombocytosis, two months after she had a splenectomy for spontaneous splenic rupture. Other reactive conditions and myeloproliferative neoplasms (MPN) were excluded, and subsequently, the diagnosis of triple-negative essential thrombocythemia (ET) was established by bone marrow histology. This case of primary thrombocythemia following splenectomy in a young patient illustrates some of the diagnostic difficulties associated with postsplenectomy thrombocytosis. Continuing reports of anecdotal experiences in managing similar complex scenarios is essential and remains the only reference for clinicians facing these rare conditions.

scholarly journals Triple-Negative Essential Thrombocythemia: Clinical-Pathological and Molecular Features. A Single-Center Cohort Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Daniele Cattaneo ◽  
Giorgio Alberto Croci ◽  
Cristina Bucelli ◽  
Silvia Tabano ◽  
Marta Giulia Cannone ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Essential Thrombocythemia ◽  
Triple Negative ◽  
Clinical Laboratory ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
Molecular Profile ◽  
Single Center ◽  
Driver Genes ◽  
Molecular Features

Lack of demonstrable mutations affecting JAK2, CALR, or MPL driver genes within the spectrum of BCR-ABL1-negative myeloproliferative neoplasms (MPNs) is currently referred to as a triple-negative genotype, which is found in about 10% of patients with essential thrombocythemia (ET) and 5–10% of those with primary myelofibrosis (PMF). Very few papers are presently available on triple-negative ET, which is basically described as an indolent disease, differently from triple-negative PMF, which is an aggressive myeloid neoplasm, with a significantly higher risk of leukemic evolution. The aim of the present study was to evaluate the bone marrow morphology and the clinical-laboratory parameters of triple-negative ET patients, as well as to determine their molecular profile using next-generation sequencing (NGS) to identify any potential clonal biomarkers. We evaluated a single-center series of 40 triple-negative ET patients, diagnosed according to the 2017 WHO classification criteria and regularly followed up at the Hematology Unit of our Institution, between January 1983 and January 2019. In all patients, NGS was performed using the Illumina Ampliseq Myeloid Panel; morphological and immunohistochemical features of the bone marrow trephine biopsies were also thoroughly reviewed. Nucleotide variants were detected in 35 out of 40 patients. In detail, 29 subjects harbored one or two variants and six cases showed three or more concomitant nucleotide changes. The most frequent sequence variants involved the TET2 gene (55.0%), followed by KIT (27.5%). Histologically, most of the cases displayed a classical ET morphology. Interestingly, prevalent megakaryocytes morphology was more frequently polymorphic with a mixture of giant megakaryocytes with hyperlobulated nuclei, normal and small sized maturing elements, and naked nuclei. Finally, in five cases a mild degree of reticulin fibrosis (MF-1) was evident together with an increase in the micro-vessel density. By means of NGS we were able to identify nucleotide variants in most cases, thus we suggest that a sizeable proportion of triple-negative ET patients do have a clonal disease. In analogy with driver genes-mutated MPNs, these observations may prevent issues arising concerning triple-negative ET treatment, especially when a cytoreductive therapy may be warranted.

scholarly journals Reticulin Accumulation in Essential Thrombocythemia: Prognostic Significance and Relationship to Therapy

2009 ◽  
Vol 27 (18) ◽  
pp. 2991-2999 ◽  
Author(s):  
Peter J. Campbell ◽  
David Bareford ◽  
Wendy N. Erber ◽  
Bridget S. Wilkins ◽  
Penny Wright ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Essential Thrombocythemia ◽  
Arterial Thrombosis ◽  
Interobserver Reliability ◽  
Prognostic Significance ◽  
Underlying Disease ◽  
Major Hemorrhage ◽  
Independent Prognostic Marker ◽  
Bone Marrow Histology ◽  
Duration Of Disease

PurposeEssential thrombocythemia (ET) manifests substantial interpatient heterogeneity in rates of thrombosis, hemorrhage, and disease transformation. Bone marrow histology reflects underlying disease activity in ET but many morphological features show poor reproducibility.Patients and MethodsWe evaluated the clinical significance of bone marrow reticulin, a measure previously shown to have relatively high interobserver reliability, in a large, prospectively-studied cohort of ET patients.ResultsReticulin grade positively correlated with white blood cell (P = .05) and platelet counts (P = .0001) at diagnosis. Elevated reticulin levels at presentation predicted higher rates of arterial thrombosis (hazard ratio [HR], 1.8; 95% CI, 1.1 to 2.9; P = .01), major hemorrhage (HR, 2.0; 95% CI, 1.0 to 3.9; P = .05), and myelofibrotic transformation (HR, 5.5; 95% CI, 1.7 to 18.4; P = .0007) independently of known risk factors. Higher reticulin levels at diagnosis were associated with greater subsequent falls in hemoglobin levels in patients treated with anagrelide (P < .0001), but not in those receiving hydroxyurea (P = .9). Moreover, serial trephine specimens in patients randomly assigned to anagrelide showed significantly greater increases in reticulin grade compared with those allocated to hydroxyurea (P = .0003), and four patients who developed increased bone marrow reticulin on anagrelide showed regression of fibrosis when switched to hydroxyurea. These data suggest that patients receiving anagrelide therapy should undergo surveillance bone marrow biopsy every 2 to 3 years and that those who show substantially increasing reticulin levels are at risk of myelofibrotic transformation and may benefit from changing therapy before adverse clinical features develop.ConclusionOur results demonstrate that bone marrow reticulin grade at diagnosis represents an independent prognostic marker in ET, reflecting activity and/or duration of disease, with implications for the monitoring of patients receiving anagrelide.

Abstract 12726: Crucial Role of Jak2 V617f-positive Myeloproliferative Neoplasm in the Development of Aortic Aneurysm

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Tetsuro Yokokawa ◽  
Tomofumi Misaka ◽  
Yusuke KIMISHIMA ◽  
Kento Wada ◽  
Keiji Minakawa ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Angiotensin Ii ◽  
Aortic Aneurysm ◽  
Mrna Expression ◽  
Abdominal Aorta ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Vascular Complication ◽  
The Impact

Objective: To investigate the impact of hematopoietic JAK2V617F, which causes myeloproliferative neoplasms (MPNs), on the development of aortic aneurysm (AA). Approach and Results: We applied a bone marrow transplantation (BMT) strategy using the donor cells from Jak2 V617F transgenic (JAK2 V617F ) mice into the lethally irradiated apolipoprotein E-deficient mice. To induce the AA formation and progression, the recipient mice (BMT mice) were subjected to continuous angiotensin II infusion. Abdominal aortic diameter in JAK2 V617F -BMT mice was significantly enlarged compared to the control wild-type (WT)-BMT mice in response to angiotensin II. The incidence of abdominal AA was significantly higher in JAK2 V617F -BMT mice than in WT-BMT mice. Hematopoietic JAK2V617F accelerated aortic elastic lamina degradation as well as activation of matrix metalloproteinase (MMP)-2 and MMP-9 in the abdominal aorta. The numbers of CD68 + macrophages and Ly6B.2 + neutrophils and cytokine expressions such as Ccl6 and Tgfb1 were significantly increased in the abdominal aorta of JAK2 V617F -BMT mice accompanied by STAT3 activation. Bone marrow-derived macrophages carrying JAK2V617F showed elevations of both Mmp2 and Mmp9 mRNA expression. Finally, we found that 23% of MPN patients with JAK2 V617F mutation showed the presence of AA and increases in TGFB3 and IL-8 mRNA expression of the peripheral leukocytes. Conclusions: Hematopoietic JAK2V617F was involved in the development of AA through increases in the infiltration of inflammatory cells and MMP activation. Our findings provide a novel feature of vascular complication of AA in MPNs due to constitutive activation of the hematopoietic JAK-STAT pathway.

scholarly journals JAK2 V617F impairs hematopoietic stem cell function in a conditional knock-in mouse model of JAK2 V617F–positive essential thrombocythemia

Blood ◽  
2010 ◽  
Vol 116 (9) ◽  
pp. 1528-1538 ◽  
Author(s):  
Juan Li ◽  
Dominik Spensberger ◽  
Jong Sook Ahn ◽  
Shubha Anand ◽  
Philip A. Beer ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Essential Thrombocythemia ◽  
Cell Function ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Transgenic Models ◽  
Disease Phenotype ◽  
Hematopoietic Stem

The JAK2 V617F mutation is found in most patients with a myeloproliferative neoplasm and is sufficient to produce a myeloproliferative phenotype in murine retroviral transplantation or transgenic models. However, several lines of evidence suggest that disease phenotype is influenced by the level of mutant JAK2 signaling, and we have therefore generated a conditional knock-in mouse in which a human JAK2 V617F is expressed under the control of the mouse Jak2 locus. Human and murine Jak2 transcripts are expressed at similar levels, and mice develop modest increases in hemoglobin and platelet levels reminiscent of human JAK2 V617F–positive essential thrombocythemia. The phenotype is transplantable and accompanied by increased terminal erythroid and megakaryocyte differentiation together with increased numbers of clonogenic progenitors, including erythropoietin-independent erythroid colonies. Unexpectedly, JAK2V617F mice develop reduced numbers of lineage−Sca-1+c-Kit+ cells, which exhibit increased DNA damage, reduced apoptosis, and reduced cell cycling. Moreover, competitive bone marrow transplantation studies demonstrated impaired hematopoietic stem cell function in JAK2V617F mice. These results suggest that the chronicity of human myeloproliferative neoplasms may reflect a balance between impaired hematopoietic stem cell function and the accumulation of additional mutations.

Clinical Implications for Patients with Low JAK2V617F Allele Burden

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1745-1745
Author(s):  
Marguerite Vignon ◽  
Dorota Jeziorowska ◽  
Pierre Hirsch ◽  
Ollivier Legrand ◽  
Nicole Casadevall ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Clinical Phenotype ◽  
Myeloproliferative Neoplasms ◽  
Kinase Domain ◽  
Jak2 Mutation ◽  
Allele Burden ◽  
Vein Thrombosis ◽  
Myeloid Neoplasms ◽  
Exon 10 ◽  
Jak2v617f Allele Burden

Abstract Abstract 1745 In classical Philadelphia-negative myeloproliferative neoplasms (MPN), JAK2V617F is considered as a driver mutation when the threshold of 1% JAK2V617F/JAK2total allele burden is reached. However a lower ratio is sometimes detected with highly sensitive assays. We investigated the clinical significance of such minor clones by describing the characteristics of 27 patients with a low JAK2V617F allele burden ranging from 0.1% to 0.99%. Material and Methods A commercially available quantitative ASO-PCR assay of 0.1% sensitivity (MutaQuant® kit, Ipsogen) was used. Two thousand five hundred consecutive blood samples were sent to our lab for JAK2V617F mutation between 2009 and 2012. Total blood DNA was extracted by an automated standardized procedure (Qiasymphony®, Qiagen). All samples were tested in duplicate. The 27 samples of our cohort were controlled using a second assay of 0.01% sensitivity (Larsen et al, BJH 2007). Thirty samples from healthy donors were also tested. High resolution melting curve (HRM) analysis of JAK2 exon 14 ruled out the possibility of an additional mutation hampering the annealing of a primer. Patients with a known classical MPN clinical phenotype were also tested for JAK2 exons 12–17 (entire pseudo-kinase domain) or for MPL exon 10 depending on the context. Results Laboratory Findings Among the 2500 samples, 735 (29.4%) were positive above 1%, 27 (1.1%) had low JAK2V617F allele burden ranging from 0.12 to 0.99%. The patient with the lowest ratio (0.12%) was not confirmed by the second assay and therefore was excluded from the study. This allowed the median to settle at 0.40%. No associated mutations were found in the JAK2 pseudo-kinase domain in patients with polycythemia vera (PV) and in MPL exon 10 in patients with essential thrombocytosis (ET) and primary myelofibrosis (PMF). Healthy patients were all tested JAK2V617F negative. Clinical Aspects The cohort included 19 men and 7 women ranging from 28 to 95 years of age (median 63 years old). Two patients had secondary acute myeloid leukaemia following JAK2V617F positive MPN indicating the presence of residual JAK2V617F cells and the negativity of the myeloblastic population. Thirteen patients (50%) had a classical MPN with a median ratio of 0.36%: 7 ET, 5 PV and 1 PMF according to WHO 2008 criteria. However a bone marrow biopsy was available for only two patients (1 ET, 1 PMF). None of them had received pegylated interferon alpha-2a. Four patients had a prior history of thrombosis: two strokes, one pulmonary embolism, two portal vein thrombosis (PVT). For one PV patient, a 6 months follow-up blood and bone marrow sample confirmed a low allele burden in the same range (0.4%) and in vitro Epo-independant erythroid colonies were observed. Five patients had other chronic myeloid neoplasms (two myelodysplastic/myeloproliferative neoplasms, one chronic eosinophilic leukaemia, one chronic myeloid leukaemia, one refractory anaemia with ring sideroblasts). Among these five, four had an abnormal karyotype. We did not observe any thrombotic event in these patients. We cannot conclude on hematological diagnosis for the last six patients: four patients were screened for JAK2 mutation because of PVT. One patient had chronic polycythemia in a context of alcohol and tobacco abuse. One patient had homozygous hemochromatosis with a normal haemoglobin level in spite of repeated phlebotomies. Discussion In this single centre study low JAK2V617F allele burden represented 1% of all samples sent for JAK2V617F study and 3.5% of JAK2V617F positive patients. Seventeen patients (65%) had classical MPN or splanchnic vein thrombosis. To our knowledge PV patients with such low JAK2V617F allele burden have not been reported in the absence of associated JAK2 pseudo-kinase domain mutation. A larger screen for cooperating mutations responsible for the PV phenotype is under process. In the context of other chronic myeloid neoplasms, the JAK2V617F mutation is thought to belong to a more complex clonal architecture mostly implicating chromatin remodeling genes. Here, the presence of a JAK2 mutation could argue in favour of clonal haematopoiesis. In conclusion the clinical phenotype of low JAK2V617F patients overlaps with classical JAK2V617F MPN. The technical implications might be challenging for molecular diagnostic platforms. More data are needed to further characterize these patients. Disclosures: No relevant conflicts of interest to declare.

Pegifna Promotes Proliferation and Myeloid Differentiation In Human Hematopoietic Progenitors In Patients With Polycythemia Vera and Essential Thrombocythemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2843-2843
Author(s):  
Katherine King ◽  
Sabina Swierczek ◽  
Katie Matatall ◽  
Kimberly Hickman ◽  
Margaret A. Goodell ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Death ◽  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Pegylated Interferon ◽  
Hematopoietic Stem ◽  
Financial Compensation ◽  
Specific Differentiation ◽  
Allelic Burden

Abstract The myeloproliferative neoplasms, polycythemia vera (PV) and essential thrombocythemia (ET), are characterized by clonal hematopoiesis that is often associated with a JAK2V617F mutation, although this does not appear to be a disease-initiating event. Treatment of PV and ET with pegylated interferon-alpha (pegInfα) has been shown to lead to hematological remission, a decrease in the JAK2V617F allelic burden in many cases, and even a reversion to polyclonal hematopoiesis. Despite promising therapeutic results, the mechanism of pegInfα-induced remission remains elusive. There are several potential mechanisms through which pegInfα may be acting, which include stimulating the immune system in order to more effectively suppress the aberrant PV clones, enhancing the activation of normal hematopoietic stem cells (HSCs), or by selectively suppressing the mutant clones. It has been previously reported that PV patients on pegInfα have an increased number of CD4+CD25+Foxp3+ T regulatory cells (Tregs) in the peripheral blood as compared to untreated or hydroxyurea treated patients (Riley Blood, 2011), which suggests that PegIFNa maybe altering immunity against the mutated clone. However, we have found that interferon treatment leads to increased proliferation of HSCs and myeloid-specific differentiation in mice (Baldridge Nature, 2010). If this finding is also true in humans, it suggests the return to polyclonality after pegInfα could also involve an increase in normal HSC proliferation. In order to address this question, we are studying the effects of pegInfα treatment on the Tregs and HSCs of PV and EV patients, when compared to hydroxyurea or untreated patients. Previously we showed that pegInfα treatment reduced the JAK2V617F allelic burden in 17 out of 32 patients. Of the 13 female patients for which clonality could be assessed, one developed polyclonal hematopoiesis with three-fold reduction of JAK2V617F allelic burden, but one developed polyclonal hematopoiesis during therapy despite no reduction in the JAK2V617F allelic burden, suggesting that pegInfα treatment is able to affect both pre-JAK2V617F clones and JAK2V617F-positive PV clones. We have now assessed changes in the HSC population in response to pegInfα treatment. Upon analysis of bone marrow samples from these same pegInfα or hydroxyurea treated patients, we found that the number of HSCs (CD45+CD34+CD38-) was increased in patients treated with pegInfα. Further we saw a decrease in the percent of quiescent HSCs in the pegInfα treated samples, measured by the percentage of cells in G0, suggesting a more actively proliferating HSC population. In agreement with these data, our RNA analysis of the HSCs showed an increase in the expression of cell cycle genes in response to short-term pegInfα treatment. In addition to this apparent increase in HSC proliferation, we also saw an increase in the number of colonies formed in methocult media from the bone marrow samples of the pegInfα treated patients, suggesting an increase in myeloid specific differentiation. When we analyzed the RNA of patients who had received long-term pegInfα treatment, we saw a transcriptional profile that was indicative of cell death. Taken together, these data suggest a model in which pegInfα treatment is allowing for a return to polyclonal hematopoiesis by inducing cell division and differentiation of normal HSCs, while suppressing the pre-JAK2V617F or JAK2V617F-positive PV and ET clones, possibly by promoting apoptosis or inducing an immune-mediated cell death. Our findings do not exclude other potential mechanisms for salutary effects of pegInfα for treatment of PV and ET (see accompanying abstract by Swierczek et al). Disclosures: Swierczek: University of Utah: No financial compensation , No financial compensation Patents & Royalties.

Tet2 Loss Accelerates The Myeloproliferative Neoplasm (MPN) Phenotype Of Jak2V617F Knockin Mice But Is Insufficient To Cause Leukemic Transformation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4095-4095
Author(s):  
Edwin Chen ◽  
Lawrence J Breyfogle ◽  
Rebekka K. Schneider ◽  
Luke Poveromo ◽  
Ross L. Levine ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Conditional Knockout ◽  
The Other ◽  
Myelogenous Leukemia ◽  
Leukemic Transformation ◽  
The Impact

Abstract TET2 mutations are early somatic events in the pathogenesis of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and myeloproliferative neoplasms (MPN) and are one of the most common genetic lesions found in these diseases. In MPN, TET2 mutations are enriched within more advanced disease phenotypes such as myelofibrosis and leukemic transformation and often co-occur with the JAK2V617F mutation, which is present in the majority of MPN patients. We have developed and characterized a Jak2V617F conditional knockin mouse (Jak2VF/+), the phenotype of which closely recapitulates the features of human MPN. To determine the impact of Tet2 loss on Jak2V617F-mediated MPN, we crossed Tet2 conditional knockout mice with Jak2VF/+ knockin and Vav-Cre transgenic mice and backcrossed the compound mutant animals. We then characterized the effects of heterozygous and homozygous loss of Tet2 on the phenotype of Jak2VF/+ mice. We assessed peripheral blood counts, histopathology, hematopoietic differentiation using flow cytometry, colony formation and re-plating capacity. We also evaluated the effects of Tet2 loss on the transcriptome of the HSC compartment using gene expression microarrays and on HSC function using competitive bone marrow transplantation assays. Similar to Jak2VF/+/VavCre+ mice, Tet2+/-/Jak2VF/+/VavCre+ and Tet2-/-/Jak2VF/+/VavCre+ mice develop leukocytosis, elevated hematocrits (HCT) and thrombocytosis. Tet2-/-/Jak2VF/+/VavCre+ mice demonstrate enhanced leukocytosis and splenomegaly compared to the other groups. All groups demonstrate myeloid expansion, erythroid hyperplasia and megakaryocytic abnormalities consistent with MPN in the bone marrow and spleen, while more prominent myeloid expansion and megakaryocytic morphological abnormalities are observed in Tet2-/-/Jak2VF/+/VavCre+ mice as compared to the other groups. Notably, we do not see the development of acute myelogenous leukemia (AML) in Tet2-/-/Jak2VF/+/VavCre+ mice at 6 months. We see enhanced expansion of lineagelowSca1+cKithigh (LSK) cells (enriched for HSC) most prominently in the spleens of Tet2+/-/Jak2VF/+/VavCre+ and Tet2-/-/Jak2VF/+/VavCre+ mice as compared to Jak2VF/+/VavCre+ mice. In colony forming assays, we find that Tet2-/-/Jak2VF/+/VavCre+ LSK cells have enhanced re-plating activity compared to Jak2VF/+/VavCre+ LSK cells and that Tet2-/-/Jak2VF/+/VavCre+ LSK cells form more colonies that Tet2-/-/Jak2+/+/VavCre+ cells. Gene expression analysis demonstrates enrichment of a HSC self-renewal signature inTet2-/-/Jak2VF/+/VavCre+ LSK cells. Concordant with this, we find that Tet2-/-/Jak2VF/+/VavCre+ LSK cells have enhanced competitive repopulation at 16 weeks as compared to Jak2VF/+/VavCre+ and Tet2+/-/Jak2VF/+/VavCre+ LSK cells. In aggregate these findings demonstrate that Tet2 loss promotes disease progression in MPN but is insufficient to drive full leukemic transformation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals MPL W515 L/K mutations in myeloproliferative neoplasms

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Sohaila Eldeweny ◽  
Hosny Ibrahim ◽  
Ghada Elsayed ◽  
Mohamed Samra
Keyword(s):  
Bone Marrow ◽  
Polycythemia Vera ◽  
Ethnic Groups ◽  
Essential Thrombocythemia ◽  
Myeloproliferative Neoplasms ◽  
Primary Myelofibrosis ◽  
Myelogenous Leukemia ◽  
Egyptian Population ◽  
Ph Chromosome ◽  
Pathological Variant

Abstract Background Myeloproliferative neoplasms (MPNs) describe a group of diseases involving the bone marrow (BM). Classical MPNs are classified into chronic myelogenous leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). This classification is based on the presence of Philadelphia (Ph) chromosome (BCR/ABL1). CML is BCR/ABL1-positive while PV, ET, and PMF are negative. JAK2 p. Val617Phe pathological variant is the most associated mutation in BCR/ABL1-negative MPNs. The frequency of JAK2 p. Val617Phe is 90–95% in PV patients, 50–60% in ET, and 40–50% in patients with PMF. Studies on MPL gene led to the revelation of a gain of function pathological variants in JAK2 p. Val617Phe-negative myeloproliferative neoplasms (MPNs). MPL p. W515 L/K pathological variants are the most common across all mutations in MPL gene. The prevalence of these pathological variants over the Egyptian population is not clear enough. In the present study, we aimed to investigate the prevalence of MPL p. W515 L/K pathological variants in the Philadelphia (Ph)-negative MPNs over the Egyptian population. Results We have tested 60 patients with Ph-negative MPNs for MPL p. W515 L/K pathological variants. Median age was 51 (22–73) years. No MPL p. W515 L/K pathological variants were detected among our patients. JAK2 p. Val617Phe in PV and PMF patients showed significantly lower frequency than other studies. Splenomegaly was significantly higher in ET patients compared to other studies. Conclusion MPL p. W515 L/K pathological variants are rare across the Egyptian Ph-negative MPNs, and further studies on a large number are recommended. MPN patients in Egypt are younger compared to different ethnic groups.

scholarly journals Combination approach to diagnosis and treatment of an elderly patient with chronic Ph-negative myeloproliferative neoplasm and concomitant surgical pathology. Clinical observation

MD-Onco ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 61-65
Author(s):  
Yu. E. Ryabukhina ◽  
P. A. Zeynalova ◽  
O. I. Timofeeva ◽  
F. M. Abbasbeyli ◽  
T. V. Ponomarev ◽  
...  
Keyword(s):  
Elderly Patient ◽  
Essential Thrombocythemia ◽  
Early Stage ◽  
Myeloproliferative Neoplasms ◽  
Myeloproliferative Neoplasm ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Left Femur ◽  
Hematopoietic Stem ◽  
Chronic Myeloproliferative Neoplasms

Chronic myeloproliferative neoplasms (CMPN), Ph-negative, are of clonal nature, develop on the level of hematopoietic stem cell and are characterized by proliferation of one or more hematopoietic pathways. Currently, the group of Ph-negative CMPN includes essential thrombocythemia, primary myelofibrosis, polycythemia vera, myeloproliferative neoplasm unclassifiable.Identification of mutations in the Jak2 (V617F), CALR, and MPL genes extended understanding of biological features of Ph-negative CMPN and improved differential diagnosis of myeloid neoplasms. Nonetheless, clinical practice still encounters difficulties in clear separation between such disorders as primary myelofibrosis, early-stage and transformation of essential thrombocythemia into myelofibrosis with high thrombocytosis. Thrombocytosis is one of the main risk factors for thromboembolic complications, especially in elderly people.A clinical case of an elderly patient with fracture of the left femur developed in the context of Ph-negative CMPN (myelofibrosis) with high level of thrombocytosis is presented which in combination with enforced long-term immobilization and presence of additional risk created danger of thrombosis and hemorrhage during surgery and in the postoperative period.

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