Concordance of assays designed for the quantification of JAK2V617F: a multicenter study

Background Many different techniques have been designed for the quantification of JAK2 V617F allelic burden, sometimes producing discrepant results. Design and Methods JAK2 V617F quantification techniques were compared among 16 centers using 11 assays based on quantitative polymerase chain reaction (with mutation-specific primers or probes, or fluorescent resonance energy transfer/melting curve analysis), allele-specific polymerase chain reaction, conventional sequencing or pyrosequencing. Results A first series of blinded samples (granulocyte DNA, n=29) was analyzed. Seven assays (12 centers) reported values inside the mean±2SD; the mean coefficient of variation was 31%. Sequencing techniq…

Germline JAK2 L611S mutation in a child with thrombocytosis

Presence of calreticulin mutations in JAK2-negative polycythemia vera

Abstract Calreticulin (CALR) mutations have recently been reported in JAK2- and MPL-negative Myeloproliferative Neoplasms (MPN), particularly essential thrombocythemia (ET) and primary myelofibrosis (PMF).The clinical course of sporadic CALR-mutated patients seems to be more indolent than that of JAK2-mutated patients. In contrast, no CALR mutation has been found in the 647 published cases of Polycythemia Vera (PV) patients tested. Consequently, CALR mutations were considered exclusive to JAK2 and MPL mutations. Since 98% of PV patients harbor a JAK2 mutation (mostly the V617F mutation in exon 14 and more rarely, in exon 12), the absence of CALR mutations in PV seemed logical. Here, we desc…

Can absolute polycythaemia be identified without measurement of the red cell mass?

Effect of 99mTc elution in vivo from red cells on red cell volumes measured using autologous 99mTc-labeled red cells: comparison with 51Cr method

The purpose of this work was to compare the measured red-cell volume (RCV) using sodium pertechnetate [RCV-99mTc] compared to the reference technique using sodium radiochromate [RCV-51Cr] and to assess the influence of technetium-99 elution on the RCV-99mTc value. Ten patients had simultaneous measurements of RCV-99mTc and RCV-51Cr. Elution of Tc-99m from red blood cells was 2.9% and led to an average overestimation of RCV-99mTc of 3.7%. The introduction of individual tracer elution rates in the RCV-99mTc calculation corrects this overestimation.

Outcome of Refractory Anemia with Ringed Sideroblasts Associated with Marked Thrombocytosis (RARS-T) In a Large Cohort of Patients

Abstract Abstract 4113 Introduction: Most of the data related to RARS-T, a rare disorder, involve small cohorts of patients. We aimed to analyze more patients also considering a variety of myelodysplastic or myeloproliferative disorders. Objective: To compare a large cohort of patients with RARS-T to refractory anemia with ringed sideroblasts (RARS), refractory anemia with ringed sideroblasts and multilineage dysplasia (RARS-MD) or essential thrombocythemia (ET) at the time of diagnosis and during disease evolution, in terms of survival and complications. Materials: Data of a European multi-center study was used including 199 cases of RARS-T 173 cases of RARS, 102 cases of RARS-MD and 431 c…

HSP90 and HSP70: Implication in Inflammation Processes and Therapeutic Approaches for Myeloproliferative Neoplasms.

Myeloproliferative neoplasms (MPN) are clonal stem cell disorders that lead to the excessive production of one or more blood cell lineages. It has been reported that, in most MPN, inflammatory cytokines are frequently increased, indicating that inflammation plays a crucial role in these disorders. Heat shock proteins (HSP) are induced in response to many stressful conditions from heat shock to hypoxia and inflammation. Besides their chaperone and cytoprotective functions, HSPs are key players during inflammation, hence the term “chaperokine.” Through their chaperone activity, HSP90, a stabilizer of many oncogenes (e.g., JAK2), and HSP70, a powerful antiapoptotic chaperone, tightly regulate …

Polyglobulie rare par mutation du gène EGLN1 : à propos d’un cas et revue de la littérature

Resume Introduction Le diagnostic etiologique d’une polyglobulie est souvent simple, l’origine etant le plus souvent acquise. Parfois il faut rechercher des formes rares, hereditaires, l’algorithme decisionnel reposant sur le dosage de l’erythropoietine serique et sur la mesure de la pression en oxygene saturant l’hemoglobine a 50 % (P50). Ces pathologies sont en rapport avec des anomalies du recepteur a l’erythropoietine, des hemoglobines hyperaffines ou a des dysfonctionnements de la voie de regulation du facteur HIF (Hypoxia-Inducible Factor) implique dans la sensibilite renale a l’hypoxie. Observation Nous rapportons le cas d’un patient de 56 ans qui presente une polyglobulie inexplique…

Incidence and Prognostic Value of FLT-3 and NPM1 Genes Abnormalities in Acute Myeloid Leukemia in the Côte D’or Population, France

Abstract Context: In acute myeloid leukemia (AML), the recently described FLT-3 and NPM1 genes abnormalities were found to have a prognostic value in AML with normal karyotype and a specific therapeutic strategy was proposed according to these abnormalities. We look for the incidence and prognostic value of these abnormalities in cases diagnosed on a well defined population. Material and Methods: AML diagnosed according to WHO classification between 01/01/2001 and 31/12/2006 in the population of the Côte d’Or department, were included. Karyotype analyses were performed in 81% of the cases. The FLT3 D835 mutation, the FLT3 internal duplication (ITD) and the NPM1 mutation were systematically…

Cohen syndrome is associated with major glycosylation defects

International audience; Cohen syndrome (CS) is a rare autosomal recessive disorder with multisytemic clinical features due to mutations in the VPS13B gene, which has recently been described encoding a mandatory membrane protein involved in Golgi integrity. As the Golgi complex is the place where glycosylation of newly synthesized proteins occurs, we hypothesized that VPS13B deficiency, responsible of Golgi apparatus disturbance, could lead to glycosylation defects and/or mysfunction of this organelle, and thus be a cause of the main clinical manifestations of CS. The glycosylation status of CS serum proteins showed a very unusual pattern of glycosylation characterized by a significant accum…

Clinical Features And Course Of Refractory Anemia With Ring Sideroblasts Associated With Marked Thrombocytosis

Background Refractory anemia with ring sideroblasts associated with marked thrombocytosis was proposed as a provisional entity in the 2001 World Health Organization classification of myeloid neoplasms and also in the 2008 version, but its existence as a single entity is contested. We wish to define the clinical features of this rare myelodysplastic/myeloproliferative neoplasm and to compare its clinical outcome with that of refractory anemia with ring sideroblasts and essential thrombocythemia. Design and Methods We conducted a collaborative retrospective study across Europe. Our database included 200 patients diagnosed with refractory anemia with ring sideroblasts and marked thrombocytosis…

High HFE mutation incidence in idiopathic erythrocytosis.

Diagnosis of exon 12‐positive polycythemia vera rescued by NGS

Abstract A JAK2V617F‐negative polycythemia associated with low serum epo needs to be tested for an exon 12 JAK2 mutation. When negative, due to potential serious complications in PV, a next generation sequencing is necessary to rule out false negative results.

Heat shock proteins in hematopoietic malignancies

Inducible heat shock proteins are molecular chaperones whose expression is increased after many different types of stress. They have a protective function helping the cell to cope with lethal conditions. Their basal expression is low in nonstressed, normal and nontransformed cells. However, in cancer cells and particularly in hematological malignancies, they are surprisingly abundant. Malignant cells have to rewire their metabolic requirements and therefore have a higher need for chaperones. This cancer cell addiction for HSPs is the basis for the use of HSP inhibitors in cancer therapy. HSPs have been shown to interact with different key apoptotic proteins. As a result, HSPs can essentiall…

Dual regulation of SPI1/PU.1 transcription factor by heat shock factor 1 (HSF1) during macrophage differentiation of monocytes

International audience; : In addition to their cytoprotective role in stressful conditions, heat shock proteins (HSPs) are involved in specific differentiation pathways, e.g. we have identified a role for HSP90 in macrophage differentiation of human peripheral blood monocytes exposed to Macrophage Colony-Stimulating Factor (M-CSF). Here, we show that deletion of the main transcription factor involved in heat shock gene regulation, heat shock factor 1 (HSF1), affects M-CSF-driven differentiation of mouse bone marrow cells. HSF1 transiently accumulates in the nucleus of human monocytes undergoing macrophage differentiation, including M-CSF-treated peripheral blood monocytes and phorbol ester-…

Leucocytosis and thrombosis at diagnosis are associated with poor survival in polycythaemia vera: a population-based study of 327 patients

Three hundred and twenty-seven patients from two population-based cohorts with an established diagnosis of polycythaemia vera were studied for prognostic risk factors for survival and leukaemia in a long-term survey. The relative survival (RS) was 72% and 46% at 10 and 20 years respectively, from the time of diagnosis. Multivariate analysis identified age >70 years, white blood cell count >13 × 10(9) /l and thrombo-embolism at diagnosis as independent risk factors. Patients with two or three of these factors had a 10 year RS of 26%, compared with 59% and 84% in patients with one and no risk factors, respectively. Age and leucocyte count are the main predicting factors for survival in polycy…

Calreticulin Mutations in Myeloproliferative Neoplasms: Comparison of Three Diagnostic Methods

International audience; Calreticulin (CALR) mutations have recently been reported in 70-84% of JAK2V617F-negative myeloproliferative neoplasms (MPN), and this detection has become necessary to improve the diagnosis of MPN. In a large single-centre cohort of 298 patients suffering from Essential Thrombocythemia (ET), the JAK2V617F, CALR and MPL mutations were noted in 179 (60%), 56 (18.5%) and 13 (4.5%) respectively. For the detection of the CALR mutations, three methods were compared in parallel: high-resolution melting-curve analysis (HRM), product-sizing analysis and Sanger sequencing. The sensitivity for the HRM, product-sizing analysis and Sanger sequencing was 96.4%, 98.2% and 89.3% re…

Leukocytosis is associated with poor survival but not with increased risk of thrombosis in essential thrombocythemia: a population-based study of 311 patients

Leukocytosis is associated with poor survival but not with increased risk of thrombosis in essential thrombocythemia: a population-based study of 311 patients

AML transformation in 56 patients with Ph- MPD in two well defined populations.

The Philadelphia chromosome-negative (Ph-) chronic myeloproliferative disorders (MPD) have an inherent tendency for transformation into acute myelogenous leukaemia (AML). The long-term rate of leukaemic transformation in unselected MPD patients was studied in well-defined MPD populations in Gothenburg, Sweden and the Cote d'Or area, Burgundy, France, respectively. Over a median observation time of 15 yr, 56 subjects (7%) out of a total of 795 patients with Ph- MPD transformed to AML. The yearly incidence of AML transformation was 0.38% in polycythaemia vera (PV), 0.37% in essential thrombocythaemia (ET) and 1.09% in idiopathic myelofibrosis (IMF). The incidence of AML development was signif…

Trends in Incidence and Survival of Myeloid Malignancies Since 1980, in the Côte D'or Department, Burgundy, France.

Abstract Abstract 3122 Poster Board III-59 Objective The Registry of Haematological Malignancies (HM) has been established on January 1st, 1980 in the department of Côte d'Or (pop 500 000 inhabitants). It was the first specialized registry in haematology in the world. During the course of 25 years (1980-2004), 5026 cases of HM were recorded including 1553 Myeloid malignancies (MM) in which entities not initially considered as malignant were taken in account such as Myelodysplastic syndrome (MDS) and some Myeloproliferative neoplasms (MPN). This allow us to present trends in incidence and survival of myeloid malignancies by entities since 1980. Method MM diagnosed in the population between …

HSP27: A Therapeutic Target in Myelofibrosis

Abstract Myelofibrosis (MF) is the most aggressive myeloproliferative neoplasms (MPN) with the highest degree of morbidity and mortality, including progressive bone marrow fibrosis resulting into bone marrow failure. JAK2 kinase inhibitors have been successfully used for a few years in MPN and more particularly for MF treatment. Despite their beneficial effects on spleen size and symptoms, JAK2 inhibitors induce low molecular and survival responses underscoring the urgent need for other therapeutic approaches. Recently, heat shock protein 90 (HSP90) - known to stabilize JAK2 - has been reported as a promising therapeutic target in MPN. However HSP90 inhibitors show toxicity and induce the e…

Leukocytosis and Thrombosis At Diagnosis Are Associated with Poor Survival in Polycythemia Vera: A Population-Based Study on 327 Patients

Abstract Abstract 2819 Introduction Polycythemia Vera (PV) is a myeloproliferative neoplasm with a long life expectancy. Consequently, long-term follow-up studies that focus on survival of PV patients must be conducted in order to register a sufficient number of events to provide informative results and statistical analyses. Most of the published studies are single-institution that focused on patients referred to hospitals, which does not necessarily reflect the course of PV in the general population. In these studies, the median age at diagnosis is younger than usually noted for PV patients in population-based studies. Moreover, survival is generally based on observed mortality, a good but…

Low incidence of <i>EPOR</i> mutations in idiopathic erythrocytosis