Myeloproliferative Neoplasms (myeloproliferative + neoplasm)

Distribution by Scientific Domains


Selected Abstracts


Phospho-STAT5 and phospho-Akt expression in chronic myeloproliferative neoplasms

BRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2009
Lizz F. Grimwade
Summary The majority of Myeloproliferative Neoplasms (MPNs) are characterised by mutations in genes encoding molecules or receptors involved in cell signalling, the most common being the JAK2 V617F mutation. This mutation leads to ligand-independent activation of downstream signalling pathways by constitutive phosphorylation. The signalling pathways affected include the Janus kinase-signal transducers and activators of transcription (JAK-STAT) and phosphotidylinositide-3 kinase (PI3K) pathways, which regulate cell survival and apoptosis respectively. Monoclonal antibodies to phospho-STAT5 and phospho-Akt were generated and assessed by immunocytochemistry on bone marrow biopsies of MPN patients with JAK2 V617F, JAK2 exon 12, MPL exon 10 and KIT D816V mutations. JAK2 V617F mutation was associated with significantly increased levels of phosphorylated STAT5 and Akt in haemopoietic cells, most marked in megakaryocytes. In contrast, JAK2 exon 12 and MPL exon 10 mutations did not affect the level of phosphorylation. In systemic mastocytosis with KIT D618V mutation there was significantly increased expression of phosphorylated STAT5 and Akt in neoplastic mast cells although there was no change in the expression in other haemopoietic cells. JAK2 V617F is associated with upregulated phosphorylation of STAT5 and Akt in megakaryocytes, and to a lesser extent in other haemopoietic cells. Immunocytochemistry of bone marrow trephines for these phospho-proteins can be used as a supplementary diagnostic test with a high negative predictive value. [source]


Acute leukemias with ETV6/ABL1 (TEL/ABL) fusion: Poor prognosis and prenatal origin

GENES, CHROMOSOMES AND CANCER, Issue 10 2010
Jan Zuna
The ETV6/ABL1 (TEL/ABL) fusion gene is a rare aberration in malignant disorders. Only 19 cases of ETV6/ABL1 -positive hematological malignancy have been published, diagnosed with chronic myeloid leukemia, other types of chronic myeloproliferative neoplasm, acute myeloid leukemia or acute lymphoblastic leukemia (ALL). This study reports three new cases (aged 8 months, 5 years, and 33 years) of ALL with the ETV6/ABL1 fusion found by screening 392 newly diagnosed ALL patients (335 children and 57 adults). A thorough review of the literature and an analysis of all published data, including the three new cases, suggest poor prognosis of ETV6/ABL1 -positive acute leukemias. The course of the disease in the two pediatric patients is characterized by minimal residual disease monitoring, using quantification of both the ETV6/ABL1 transcript and immunoreceptor gene rearrangements. Eosinophilia could not be confirmed as a hallmark of the ETV6/ABL1 -positive disease. Studies of neonatal blood spots demonstrated that, in the child diagnosed at five years, the ETV6/ABL1 fusion initiating the ALL originated prenatally. © 2010 Wiley-Liss, Inc. [source]


Treatment options for hydroxyurea-refractory disease complications in myeloproliferative neoplasms: JAK2 inhibitors, radiotherapy, splenectomy and transjugular intrahepatic portosystemic shunt

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2010
Elena Mishchenko
Abstract Clinical care of patients with polycythemia vera, essential thrombocythemia and myelofibrosis (MF) requires not only a broad understanding of general treatment principles but also familiarity with the management of hydroxyurea-refractory disease complications. The latter include progressive splenomegaly, symptomatic portal hypertension (e.g. ascites, variceal bleeding), pulmonary hypertension, bone pain, intractable pruritus, constitutional symptoms (e.g. fatigue, night sweats) and cachexia (i.e. loss of lean body mass, general ill health, poor appetite). Some of these symptoms are directly or indirectly related to extramedullary hematopoiesis (EMH) and others to proinflammatory cytokine excess. Results from recent clinical trials of JAK inhibitors suggest remarkable activity in MF-associated constitutional symptoms, cachexia, pruritus and hydroxyurea-refractory splenomegaly. Involved-field radiotherapy is best utilized in the setting of EMH-associated symptoms, including ascites, bone (extremity) pain and pulmonary hypertension. Splenectomy is indicated in the presence of drug-refractory splenomegaly and frequent red cell transfusion requirement. Transjugular intrahepatic portosystemic shunt is used to alleviate symptoms of portal hypertension. [source]


Chromosome 1 abnormalities in myeloid malignancies: a literature survey and karyotype,phenotype associations

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2010
Domenica Caramazza
Abstract Chromosome 1 is the largest human chromosome and contains over 1600 known genes and 1000 novel coding sequences or transcripts. It is, therefore, not surprising that recurrent chromosome 1 abnormalities are regularly encountered in both neoplastic and non-neoplastic medical conditions. The current review is focused on myeloid malignancies where we summarize the relevant published literature and discuss specific karyotype,phenotype associations. We show that chromosome 1 abnormalities are most frequent in BCR-ABL -negative classic myeloproliferative neoplasms (MPN): polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Specific abnormalities include duplications (e.g. 1q12,1q32 in PV, 1q21,32,1q32,44 in post-PV MF or PMF), deletions (e.g. 1p13,36,pter in PV or PMF, 1q21 in PMF) and unbalanced translocations involving chromosome 6, such as der(6)t(1;6)(q21,25;p21.3,23), and other partner chromosomes involving 1q10/1p11 and 1q21,25 breakpoints. Although occasionally seen in chronic phase MPN, unbalanced 1;7 translocations, e.g. der(1;7)(q10;p10), are usually seen in acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and post-MPN AML/MDS. These observations suggest that certain chromosome 1 regions, especially 1q21,1q32 and 1p11,13, might harbor oncogenes or tumor suppressor genes that are pathogenetically relevant to both chronic and advanced phases of MPN. [source]


A new era for small molecule screening: from new targets, such as JAK2 V617F, to complex cellular screens

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2009
Stefan N. ConstantinescuArticle first published online: 21 JAN 200
Traditionally reserved to research and development in pharmaceutical companies, screening of small molecule libraries is rapidly becoming an approach undertaken by academic laboratories. Novel cellular assays, sensitive systems to probe function, emerging new molecular targets are just some of the reasons explaining this shift. Targets of small molecules identified in cellular screens begin to be amenable to identification by elegant genetic approaches, such as probing toxicity of candidate small molecules on libraries of genetically modified yeast strains. Several new targets, such as JAK2 V617F, an activated JAK2 (Janus Kinase 2) mutant genetically associated with the majority of human myeloproliferative neoplasms, are being actively pursued. In this Review Series, we will learn how libraries of small molecules are harnessed to identify novel molecules, that alone or in combination, have the ability to alter cell fate, cell signalling, gene expression or response to extracellular cues. [source]


CXCR4-independent rescue of the myeloproliferative defect of the gata1low myelofibrosis mouse model by Aplidin®,

JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2010
Maria Verrucci
The discovery of JAK2 mutations in Philadelphia-negative myeloproliferative neoplasms has prompted investigators to evaluate mutation-targeted treatments to restore hematopoietic cell functions in these diseases. However, the results of the first clinical trials with JAK2 inhibitors are not as promising as expected, prompting a search for additional drugable targets to treat these disorders. In this paper, we used the hypomorphic Gata1low mouse model of primary myelofibrosis (PMF), the most severe of these neoplasms, to test the hypothesis that defective marrow hemopoiesis and development of extramedullary hematopoiesis in myelofibrosis is due to insufficient p27Kip1 activity and is treatable by Aplidin®, a cyclic depsipeptide that activates p27Kip1 in several cancer cells. Aplidin® restored expression of Gata1 and p27Kip1 in Gata1low hematopoietic cells, proliferation of marrow progenitor cells in vitro and maturation of megakaryocytes in vivo (reducing TGF-,/VEGF levels released in the microenvironment by immature Gata1low megakaryocytes). Microvessel density, fibrosis, bone growth, and marrow cellularity were normal in Aplidin®-treated mice and extramedullary hematopoiesis did not develop in liver although CXCR4 expression in Gata1low progenitor cells remained low. These results indicate that Aplidin® effectively alters the natural history of myelofibrosis in Gata1low mice and suggest this drug as candidate for clinical evaluation in PMF. J. Cell. Physiol. 225: 490,499, 2010. © 2010 Wiley-Liss, Inc. [source]


Chromosome 8p11.2 translocations: Prevalence, FISH analysis for FGFR1 and MYST3, and clinicopathologic correlates in a consecutive cohort of 13 cases from a single institution,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 4 2010
Mrinal M. Patnaik
Chromosome 8p11.2 translocations result in diverse oncogenic fusion genes involving FGFR1 or MYST3. Among 24,262 unique patient cytogenetic studies performed at the Mayo Clinic, 8p11.2 translocations were identified in 14 cases (,0.06%). FISH analysis was performed in 13 patients (12 had myeloid neoplasms) and revealed abnormalities of MYST3 (n = 4) or FGFR1 (n = 4) in eight patients. MYST3 abnormalities were associated with acute myeloid leukemia (AML), M4 in three and M6 in one. Three of the four FGFR1 -rearranged cases were associated with myeloproliferative neoplasms but none, including the two with sole 8p11.2, displayed the typical phenotype for stem cell leukemia/lymphoma (SCLL) and only one had eosinophilia; the fourth case had AML-M4. FISH did not reveal FGFR1 involvement in the one patient with SCLL. We conclude that neither the SCLL phenotype nor blood eosinophilia is a consistent feature of FGFR1 -associated 8p11.2 translocations; conversely, FISH might not always reveal FGFR1 involvement in typical SCLL. Am. J. Hematol. 2010. © 2010 Wiley-Liss, Inc. [source]


ASH 2009 meeting report,Top 10 clinically oriented abstracts in myeloproliferative neoplasms,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 3 2010
Ayalew Tefferi
No abstract is available for this article. [source]


Leukocytosis as a risk factor for thrombosis in myeloproliferative neoplasms,biologically plausible but clinically uncertain

AMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2010
Ayalew Tefferi
No abstract is available for this article. [source]


Prodromal myeloproliferative neoplasms: The 2008 WHO classification,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2010
Hans Michael Kvasnicka
The concept of prodromal chronic myeloproliferative neoplasms has been endorsed by the WHO classification implicating a stepwise evolution of disease. Histology of the bone marrow (BM) and borderline to mildly expressed clinical features play a pivotal role for diagnosing prefibrotic-early primary myelofibrosis. By lowering the platelet count for essential thrombocythemia and regarding BM morphology, early manifestations are tackled. Pre-polycythemic stages of polycythemia vera with a low hemoglobin level at onset are diagnosed by positive JAK2V617F mutation status, a low erythropoietin value, and characteristic BM features. The revised WHO classification incorporates hematological, morphological, and moleculargenetic parameters to generate a consensus-based working diagnosis. Am. J. Hematol., 2010. © 2009 Wiley-Liss, Inc. [source]


Cytogenetic correlates of TET2 mutations in 199 patients with myeloproliferative neoplasms,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2010
Kebede Hussein
No abstract is available for this article. [source]


Absence of the JAK2 exon 12 mutations in patients with splanchnic venous thrombosis and without overt myeloproliferative neoplasms

AMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2009
Alessia Fiorini
No abstract is available for this article. [source]


Fusion of PDGFRB to two distinct loci at 3p21 and a third at 12q13 in imatinib-responsive myeloproliferative neoplasms

BRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2010
Claire Hidalgo-Curtis
Summary We identified four patients who presented with BCR-ABL1 negative myeloproliferative neoplasms and cytogenetically visible abnormalities of chromosome band 5q31-35. Fluorescence in situ hybridization indicated that the platelet-derived growth factor receptor , gene (PDGFRB) was disrupted in all four cases and 5, rapid amplification of cDNA ends identified in-frame mRNA fusions between PDGFRB and WDR48 (3p21), GOLGA4 (3p21) and BIN2 (12q13). Strikingly, all three genes encode proteins involving intracellular trafficking. Imatinib, a known inhibitor of PDGFR,, selectively blocked the growth of t(3;5) myeloid colonies and produced clinically significant responses in all patients. We conclude that PDGFRB fuses to diverse partner genes in atypical myeloproliferative neoplasms (MPNs). Although very rare, identification of these fusions is critical for proper management of affected individuals. [source]


Phospho-STAT5 and phospho-Akt expression in chronic myeloproliferative neoplasms

BRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2009
Lizz F. Grimwade
Summary The majority of Myeloproliferative Neoplasms (MPNs) are characterised by mutations in genes encoding molecules or receptors involved in cell signalling, the most common being the JAK2 V617F mutation. This mutation leads to ligand-independent activation of downstream signalling pathways by constitutive phosphorylation. The signalling pathways affected include the Janus kinase-signal transducers and activators of transcription (JAK-STAT) and phosphotidylinositide-3 kinase (PI3K) pathways, which regulate cell survival and apoptosis respectively. Monoclonal antibodies to phospho-STAT5 and phospho-Akt were generated and assessed by immunocytochemistry on bone marrow biopsies of MPN patients with JAK2 V617F, JAK2 exon 12, MPL exon 10 and KIT D816V mutations. JAK2 V617F mutation was associated with significantly increased levels of phosphorylated STAT5 and Akt in haemopoietic cells, most marked in megakaryocytes. In contrast, JAK2 exon 12 and MPL exon 10 mutations did not affect the level of phosphorylation. In systemic mastocytosis with KIT D618V mutation there was significantly increased expression of phosphorylated STAT5 and Akt in neoplastic mast cells although there was no change in the expression in other haemopoietic cells. JAK2 V617F is associated with upregulated phosphorylation of STAT5 and Akt in megakaryocytes, and to a lesser extent in other haemopoietic cells. Immunocytochemistry of bone marrow trephines for these phospho-proteins can be used as a supplementary diagnostic test with a high negative predictive value. [source]


Prevalence of the JAK2 V617F mutation in patients with unprovoked venous thromboembolism of common sites and without overt myeloproliferative neoplasms

BRITISH JOURNAL OF HAEMATOLOGY, Issue 6 2009
Tommaso Za
No abstract is available for this article. [source]