Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interferon alfa has been used in the treatment of myeloproliferative disorders, particularly chronic myeloid leukemia, polycythemia vera, and idiopathic thrombocythemia. The effectiveness of interferon alfa in agnogenic myeloid metaplasia needs additional evaluation, although preliminary evidence suggests that it may be more efficacious when used in the cellular (ie, proliferative) phase than when the marrow is fibrotic or osteosclerotic. Cytogenetic and molecular changes after interferon alfa therapy are apparent in patients with chronic myeloid leukemia, as manifested by change in the Philadelphia chromosome and BCR-ABL gene, respectively. The exact role of interferon in prolonging the life of chronic myeloid leukemia patients, however, remains to be determined in larger studies of longer duration. Interferon treatment seems to be well tolerated, and the frequency of treatment-limiting toxicity is low. Data to date suggest that interferon alfa may be a new and effective drug for the treatment of the myeloproliferative disorders.
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PMID:Interferon in the treatment of myeloproliferative diseases. 211 94

We have investigated the involvement of tumor suppressor genes (p53 and RB1) and dominantly acting oncogenes (Ras family genes) in BCR/ABL positive and negative chronic myeloproliferative disorders (CMPD) at different stages of the disease, including 26 cases of BCR/ABL+ chronic myeloid leukemia (CML) blast crisis, 9 myelosclerosis with myeloid metaplasia, 4 polycythemia vera, 10 essential thrombocythemia, 1 juvenile CML, and 8 BCR/ABL- CML. The presence of mutations in p53 exons 5 through 9, as well as in RB1 exons 10-27 and in N-, K-, H-Ras exons 1 and 2 was tested by the PCR-Single Strand Conformation Polymorphism technique and by PCR-Direct Sequencing. In addition, Southern blot analysis was used to investigate the occurrence of gross rearrangements in the p53 gene as well as loss of heterozygosity at 17p13, the site of p53. Acute phase BCR/ABL-CMPD cases displayed a high frequency of p53 (2/7) and Ras (3/7) lesions, whereas BCR/ABL- CMPD in chronic phase displayed only germline p53 and Ras sequences. Conversely, p53 inactivation was restricted to only 1/26 cases of BCR/ABL+ CML blast crisis. No alterations in the RB1 gene were detected in any of the cases analyzed. These data indicate that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL- CMPD and that the molecular mechanisms of tumor progression may be different in BCR/ABL+ versus BCR/ABL-CMPD.
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PMID:Molecular mechanisms of tumor progression in chronic myeloproliferative disorders. 815

Philadelphia (Ph) chromosome-positive leukemias, with the bcr-abl gene translocation, have a dismal prognosis. The identification of Ph-positive patients is vitally important because only aggressive therapeutic approaches, such as allogeneic bone marrow transplantation, may result in long-term disease-free survival. Routine diagnostic methods, such as Southern blot analysis and cytogenetics, may lead to false-negative results. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis is considered the most sensitive tool for the detection of the bcr-abl translocation, and it is widely used alone or in combination with karyotyping or Southern blot analysis to identify Ph-positive cases. In this study, we used fluorescence in situ hybridization (FISH) with BCR and ABL double-color probes for detecting Ph-positive leukemias. The FISH results were compared with the results of cytogenetic and RT-PCR analyses in 75 patients with leukemia or other myeloproliferative syndromes (chronic myeloid leukemia, 30; acute lymphoblastic leukemia, 24; acute myelogenous leukemia, 6; essential (hemorrhagic) thrombocythemia, 12; chronic myelomonocytic leukemia, 2; and polycythemia vera, 1). FISH analysis proved to be simple, extremely reliable and sensitive; bcr-abl fusion detection was successful in the presence of all types of molecular junctions i.e., (b2a2, b3a2, and e1a2). Furthermore, a Ph-positive case that proved fusion negative by RT-PCR was identified as positive by FISH. The sensitivity of RT-PCR and FISH related to Ph-positive cases were 97% and 100%, respectively. Regarding specificity, in 4 (5%) of 75 patients, RT-PCR provided false-positive results. Cross-contamination was identified because a new specimen was harvested and reanalyzed when FISH, cytogenetics, and RT-PCR results were contradictory. We believe FISH is an optimal diagnostic method to detect bcr-abl translocation that can be used alone or to validate the results of RT-PCR analysis.
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PMID:A comparative analysis of FISH, RT-PCR, and cytogenetics for the diagnosis of bcr-abl-positive leukemias. 942 14

Philadelphia-negative (Ph-neg) essential thrombocythemia (ET), polycythemia vera (PV) and idiopathic myelofibrosis (IMF) form a syndrome of related chronic myeloproliferative disorders (MPD) characterized by expansion of one or more of the hematopoietic progenitors. Based on our previous finding of BCR-ABL transcripts in bone marrow aspirates of 12/25 Ph-neg ET patients, we have expanded our study up to 40 patients. Here we describe the rational for performing this study and report 19 of 40 patients who have BCR-ABL transcripts in their BM, 11 of them carry b3a2 and 8 carry b2a2. The two groups, BCR-ABL positive and negative, were completely identical with regard to clinical characteristics and laboratory data. We also report preliminary results of our attempt to examine concordance or discordance of BCR-ABL expression in the peripheral blood and bone marrow of Ph-neg ET patients.
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PMID:Significance of BCR-ABL transcripts in bone marrow aspirates of Philadelphia-negative essential thrombocythemia patients. 1019 23

The chronic myeloproliferative disorders are clonal hematopoietic stem cell disorders and include chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and agnogenic myeloid metaplasia (AMM). These diseases are characterized by clonal expansion of the myeloid compartment, increased marrow angiogenesis, and varying risks for blastic transformation. A clear molecular abnormality exists (t(9;22) leading to the fusion of BCR-Abl) only for CML, which led to effective targeted therapy (STI-571). Since no similar pathogenetic mechanism has been discovered for the t(9;22) negative chronic myeloproliferative disorders, their respective diagnosis is currently based on a variety of rather cumbersome diagnostic criteria. Polycythemia vera is distinguished from reactive erythrocytosis through erythropoietin independent growth of erythroid progenitors in vitro, suppressed levels of endogenous erythropoietin, possible overexpression of PRV-1 (polycythemia rubra vera-1), decreased c-Mpl expression on megakaryocytes, as well as overexpression of bcl-xL, and potentially aberrant activity of the Jak-Stat pathway. ET is defined by thrombocytosis and is distinguished from reactive states by decreased megakaryocyte c-Mpl expression, and a propensity for thrombosis. AMM has been associated with a variety of observations including increased concentrations of pro-fibrotic cytokines, increased angiogenesis, and myeloid expansion. AMM is often indistinguishable clinically and prognostically from the advanced phases of other CMPD (specifically post-polycythemic and post-thrombocythemia myeloid metaplasia), all of which are subentities of a diagnosis of myelofibrosis with myeloid metaplasia (MMM). The management of CMPD patients is quite varied given the broad range of disease severity and survival observed. The role of stem cell transplantation is limited by the age and comorbidities encountered in CMPD patients. Since no broadly applicable therapy effects the mortality of the CMPD, management currently focuses on the prevention/palliation of disease morbidity (i.e. vascular complications, pruritus, organomegaly, constitutional symptoms). Palliative strategies which currently focus on non-specific myelosuppresion, will hopefully be soon replaced by targeted therapies as insight into pathogenetic mechanisms of these diseases evolves.
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PMID:Clinical and scientific advances in the Philadelphia-chromosome negative chronic myeloproliferative disorders. 1243 Sep 25

The association of myeloproliferative and lymphoproliferative disorders is well known after cytotoxic drug or radiation exposure, while it is remarkably rare prior to therapy. We report on a patient simultaneously diagnosed as having polycythemia vera and II3A follicle center cell non-Hodgkin lymphoma (grade 1). At this timepoint, he is on 12-year follow-up, characterized by post-polycythemia myeloid metaplasia with myelofibrosis and persistent complete remission of lymphoma. The conventional marrow cytogenetic analysis performed during the course of the disease demonstrated an abnormal karyotype with deletion of the long arm of chromosome 20 and trisomy 8, while molecular analysis failed to detect BCR-ABL rearrangement in peripheral blood cells. To the best of our knowledge based on a computer-aided review of the literature (MED-LINE 1966-2002), this is the sixth case of concomitant primary polycythemia vera and lymphoma of non-Hodgkin type. Besides, there is a single literature report on polycythemia vera coexisting with the Hodgkin's lymphoma. In our case as well as in the recorded ones, two independent malignant clones of myeloid and lymphoid origin, respectively, seem to have arisen. Further reports, supported by chromosomal and molecular studies, could improve our knowledge on this extremely infrequent disease association.
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PMID:Concomitant primary polycythemia vera and follicle center cell non-Hodgkin lymphoma: a case report and review of the literature. 1253 50

Myeloproliferative disorders include several pathologies sharing the common feature of being clonal hematopoietic stem cell diseases. The molecular basis of chronic myeloid leukemia was characterized many years ago with the discovery of the t(9;22) translocation and its product the BCR-ABL oncoprotein. The recent finding of a recurrent mutation in the Janus 2 tyrosine kinase gene is a major advance in our understanding of the pathogenesis of several other myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and idiopathic myelofibrosis. Although this work clearly identifies a frequent ( approximately 50%) subgroup of myeloproliferative disorders and explains most biological abnormalities described so far, it also raises the major question of how a single mutation can explain disease heterogeneity. Such a recurrent and unique mutation leading to a tyrosine kinase deregulation would make a suitable target for the development of specific therapies.
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PMID:A JAK2 mutation in myeloproliferative disorders: pathogenesis and therapeutic and scientific prospects. 1627 12

Activating tyrosine kinase (TK) mutations disrupt cellular proliferation and survival pathways and are increasingly recognized as a fundamental cause of human cancers. Until very recently, the only TK mutations widely observed in myeloid neoplasia were the BCR/ABL1 fusions characteristic of chronic myeloid leukemia and some acute leukemias, and FLT3 activating mutations in a minority of acute myeloid leukemias. Several rare TK mutations are found in various atypical myeloproliferative disorders, but big pieces of the pathobiological puzzle were glaringly missing. In the first half of 2005, one gap was filled in: 7 studies identified the same acquired amino acid substitution (V617F) in the Janus kinase 2 (JAK2) TK in large numbers of patients with diverse clonal myeloid disorders. Most affected patients suffer from the classic BCR/ABL1-negative myeloproliferative disorders (MPD), especially polycythemia vera (74% of n = 506), but a subset of people with essential thrombocythemia (36% of n = 339) or myelofibrosis with myeloid metaplasia (44% of n = 127) bear the identical mutation, as do a few individuals with myelodysplastic syndromes or an atypical myeloid disorder (7% of n = 556). This long-sought common mutation in BCR/ABL1-negative MPD raises many provocative biological and clinical questions, and demands re-evaluation of prevailing diagnostic algorithms for erythrocytosis and thrombocytosis. JAK2 V617F may provide novel molecular targets for drug therapy, and suggests other places to seek cooperating mutations or mutations associated with similar phenotypes. The story of this exciting finding will unfold rapidly in the years ahead, and ongoing developments will be important for all hematologists to understand.
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PMID:JAK2 V617F in myeloid disorders: what do we know now, and where are we headed? 1632 48

The classical myeloproliferative disorders (MPDs) are comprised of the clonal, BCR-ABL-negative, chronic myeloid disorders of essential thrombocythemia, polycythemia vera, and myelofibrosis with myeloid metaplasia. Management of these disorders remains a significant challenge due to the varied range of prognosis and phenotypic manifestations. Curative therapy, achieved in some patients through allogeneic stem cell transplantation, is elusive or inappropriate in most. Additionally, no available medical therapy has been shown to clearly improve survival or delay disease progression. Current management involves an emphasis on prevention of thrombohemorrhagic complications (through aspirin treatment, phlebotomy and cytoreduction in high-risk patients) in early-stage patients and symptomatic care in those with advanced disease. Leukemic transformation from MPDs remains a rapidly fatal complication, unresponsive to current therapies. Recent elucidation of the role of the activating tyrosine kinase mutation JAK2 (V617F) is anticipated to usher in an era of greater understanding and targeted therapy for the MPDs.
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PMID:Practical management of classical myeloproliferative disorder patients: a clinician's guide. 1692 18

JAK2V617F, a somatic gain-of-function mutation involving the JAK2 tyrosine kinase gene, occurs in nearly all patients with polycythemia vera (PV) but also in a variable proportion of patients with other myeloid disorders; mutational frequency is estimated at approximately 50% in both essential thrombocythemia (ET) and myelofibrosis (MF), up to 20% in certain subcategories of atypical myeloproliferative disorder (atypical MPD), less than 3% in de novo myelodysplastic syndrome (MDS) or acute myeloid leukemia, and 0% in chronic myeloid leukemia (CML). Accordingly, there is now molecular justification for grouping PV, ET, and MF together in a distinct MPD category (i.e., classic, BCR-ABL(-) MPD) that is separate from chronic myeloid leukemia (CML), MDS, and atypical MPD. To date, JAK2V617F has not been described in patients with reactive myeloproliferation, lymphoid disorders, or solid tumor. Therefore, the presence of JAK2V617F strongly suggests an underlying MPD and it is therefore reasonable to consider JAK2V617F-based laboratory tests for the evaluation of polycythemia, primary thrombocytosis, unexplained leukocytosis, bone marrow fibrosis, or abdominal vein thrombosis. Current information on disease-specific prognostic relevance of JAK2V617F is inconclusive and confounded by inter-study differences in the performance of mutation screening assays. Regardless, the discovery of JAK2V617F has reinforced the pathogenetic contribution of JAK-STAT signaling in MPD and identifies JAK2 as a valid drug target.
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PMID:Classification, diagnosis and management of myeloproliferative disorders in the JAK2V617F era. 1712 67


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