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)

Virtually every aspect concerning the occurrence of acute leukemia in polycythemia vera is controversial. However, a list of those factors believed to have importance in leukemogenesis in this disease includes: maleness, ethnic origin, the presence of myeloid metaplasia and/or early WBC precursors in the peripheral blood at the time of presentation, the influence of prolonged survival, and a possible dose-response relationship with 32P treatment. Many of the features of PV suggest that it is a malignant disease per se, with other factors (such as clones of cells, or altered host response) combining to increase the leukemogenic potential of the agents used to control the disease. It does appear that the incidence of AL in PV treated with 32P and/or x-ray is many times higher than that for PV treated with phlebotomy alone. However, overall survival for 32P-treated patients appears to be longer than that for phlebotomy treatment. Further, for both 32P and phlebotomy treatments, patients with AL do not die an an earlier age than do patients not developing this complication. Since the transformation of PV into AL has been described in more than 20 patients treated with phlebotomy alone, and in more than 30 patients treated with chemotherapy and phlebotomy, the question concerning the occurrence of AL in PV no longer appears to revolve around whether this is a function of the leukemogenicity of 32P or the effect of prolongation of survival. The occurrence of AL in multiple myeloma, lymphomas, other malignancies, and in nonmalignant diseases following treatment with myelosuppressive agents, forces one to consider the leukemogenic potential of any agent capable of suppressing the panmyelopathy of this disease, as well as the inherent tendency to AL of the "untreated" disease. Hopefully, the next decade will give us a more complete understanding of the complex interrelationships between PV, its treatment, and AL.
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PMID:Acute leukemia in polycythemia vera. 76 88

Chromosomal findings are reported in three patients with acute myelomonocytic leukemia and in one with reticulosarcoma leukemia who had been treated for multiple myeloma with melphalan and X-ray. All four patients had striking chromosomal anomalies. An iatrogenic causation of aneuploidy is suggested. This is supported by chromosomal findings in patients with acute leukemia following polycythemia vera and Hodgkin's disease; practically all of the leukemias have been aneuploid. A comparison is made of such "secondary" acute leukemias with "primary" acute leukemias that are aneuploid in only 40% of the cases. Chromosomal changes are not considered to be the initial event in leukemogenesis.
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PMID:Chromosome studies in acute leukemias developing in patients with multiple myeloma. 109 66

Myelodysplasia and the myeloproliferative disorders are clonal hematopoietic stem cell disorders with heterogeneous clinical presentations and prognoses. This review highlights some of the recent progress that has been made in these disorders. Specifically, a number of studies have enhanced our understanding of the pathogenesis of these disorders, and potentially useful animal models for primary myelofibrosis have been developed. New, clinically useful prognostic scoring systems have been devised for myelodysplasia and for primary myelofibrosis. New chemotherapeutic approaches and nonmyelosuppressive alternative therapies for myelodysplasia have been studied. Data on the use of interferon for polycythemia vera and the potential leukemogenesis of hydroxyurea have recently become available. Finally, continued progress has been made in the use of allogeneic (related and unrelated donor) and autologous stem cell transplantation for myelodysplasia.
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PMID:Myelodysplasia and myeloproliferative disorders. 926 54

Polycythemia vera (PV), one of the chronic myeloproliferative disorders (MPD), is characterized by predominant erythroid proliferation and secondary platelet proliferation, and by progression from a proliferative stage to a metastatic phase and finally a malignant phase. These characteristics expose patients to increased risk for thrombohemorrhagic complications, myeloid metaplasia, myelofibrosis, and acute leukemic conversion irrespective of treatments. Currently, there are three agents-hydroxyurea (HU), interferon-alfa (IFN-alpha), and anagrelide-that differ in mechanisms of action and in treating specific phenotypic manifestations of PV, suggesting a potential role for combination therapy. They also differ widely in side effects profiles and severity. Because of the differing risks for long-term complications associated with these agents, age is an important variable in selecting treatments. Patients at high risk for thrombohemorrhagic complications all require cytoreduction, as do patients at intermediate risk who are not effectively managed by phlebotomy and low-dose aspirin. In younger patients, the safest and most effective combination treatment appears to be anagrelide plus IFN-alpha, while in older patients anagrelide plus hydroxyurea may be effective. HU is used sparingly in younger patients because of the long-term increased risk of mutagenicity and possibly leukemogenesis. IFN-alpha is particularly indicated for patients with myeloid metaplasia evidenced by splenomegaly. Anagrelide, which acts on the mature megakaryocyte to prevent platelet budding, is uniquely efficacious in the control of platelet counts.
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PMID:Modern treatment strategies in polycythemia vera. 1268 79

The four Janus kinases (JAKs) comprise a family of intracellular, nonreceptor tyrosine kinases that first gained attention as signaling mediators of the type I and type II cytokine receptors. Subsequently, the JAKs were found to be involved in signaling downstream of the insulin receptor, a number of receptor tyrosine kinases, and certain G-protein coupled receptors. Although a number of cytoplasmic targets for the JAKs have been identified, their predominant action was found to be the phosphorylation and activation of the signal transducers and activators of transcription (STAT) factors. Through the STATs, the JAKs activate gene expression linked to cellular stress, proliferation, and differentiation. The JAKs are especially important in hematopoiesis, inflammation, and immunity, and aberrant JAK activity has been implicated in a number of disorders including rheumatoid arthritis, psoriasis, polycythemia vera, and myeloproliferative diseases. Although once thought to reside strictly in the cytoplasm, recent evidence shows that JAK1 and JAK2 are present in the nucleus of certain cells often under conditions associated with high rates of cell growth. Nuclear JAKs have now been shown to affect gene expression by activating other transcription factors besides the STATs and exerting epigenetic actions, for example, by phosphorylating histone H3. The latter action derepresses global gene expression and has been implicated in leukemogenesis. Nuclear JAKs may have a role as well in stem cell biology. Here we describe recent developments in understanding the noncanonical nuclear actions of JAK1 and JAK2.
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PMID:JAKs go nuclear: emerging role of nuclear JAK1 and JAK2 in gene expression and cell growth. 2189 41

Myelofibrosis is a myeloproliferative neoplasm that occurs de novo (primary myelofibrosis) or results from the progression of polycythemia vera or essential thrombocytemia (hereafter designated as secondary myelofibrosis or post-polycythemia vera/ essential thrombocythemia myelofibrosis). To progress in the understanding of myelofibrosis and to find molecular prognostic markers we studied 104 samples of primary and secondary myelofibrosis at chronic (n=68) and acute phases (n=12) from 80 patients, by using array-comparative genomic hybridization and sequencing of 23 genes (ASXL1, BMI1, CBL, DNMT3A, EZH2, IDH1/2, JAK2, K/NRAS, LNK, MPL, NF1, PPP1R16B, PTPN11, RCOR1, SF3B1, SOCS2, SRSF2, SUZ12, TET2, TP53, TRPS1). We found copy number aberrations in 54% of samples, often involving genes with a known or potential role in leukemogenesis. We show that cases carrying a del(20q), del(17) or del(12p) evolve in acute myeloid leukemia (P=0.03). We found that 88% of the cases were mutated, mainly in signaling pathway (JAK2 69%, NF1 6%) and epigenetic genes (ASXL1 26%, TET2 14%, EZH2 8%). Overall survival was poor in patients with more than one mutation (P=0.001) and in patients with JAK2/ASXL1 mutations (P=0.02). Our study highlights the heterogeneity of myelofibrosis, and points to several interesting copy number aberrations and genes with diagnostic and prognostic impact.
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PMID:Array comparative genomic hybridization and sequencing of 23 genes in 80 patients with myelofibrosis at chronic or acute phase. 2442 86