Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The myeloproliferative disorders (MPDs) are chronic malignant conditions originating from the clonal expansion of a multipotential hematopoietic stem cell. These diseases include polycythemia vera (PV), essential thrombocythenia, atypical chronic myeloid leukemia, idiopathic hypereosinophilic syndrome (HES), agnogenic myeloid metaplasia with myelofibrosis, and others. Receptor tyrosine kinases-the platelet-derived growth factor receptors (PDGFRs) and c-Kit-and their respective ligands have been implicated in the pathogenesis of MPDs. For example, a constitutively activated PDGFR fusion tyrosine kinase (FIP1L1-PDGFRA) was identified in some patients with HES, a disease characterized by sustained overproduction of eosinophils that has been classified by the World Health Organization as a chronic subtype of the MPDs. Imatinib is a selective inhibitor of PDGFRs, c-Kit, Abl and Arg protein-tyrosine kinases, as well as Bcr-Abl, the oncogenic tyrosine kinase that causes chronic myeloid leukemia. The efficacy of imatinib in treating HES, systemic mast cell disease, chronic myelomonocytic leukemia associated with PDGFRbeta fusion genes, and (to a lesser extent) PV and idiopathic myelofibrosis was reviewed from institutional experience and a review of the literature. In 3 studies that involved 11 patients with PV, 10 patients had reductions in phlebotomy with imatinib. Eight studies of 42 patients with HES indicated that 70% achieved complete hematologic remissions with imatinib. Four studies of 6 patients with MPD indicated responses with imatinib in 5 patients. Insight into the molecular pathogenesis of MPDs will improve the definitions of different disease categories and suggests that signal transduction inhibition is likely to be an increasingly important treatment option in the future.
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PMID:Beyond chronic myelogenous leukemia: potential role for imatinib in Philadelphia-negative myeloproliferative disorders. 1513 47

Use of the term "idiopathic hypereosinophilic syndrome (HES)" has highlighted our basic lack of understanding of the molecular pathophysiology of eosinophilic disorders. However, over the last 10 years, the study of hypereosinophilia has enjoyed a revival. This interest has been rekindled by two factors: (1) the development of increasingly sophisticated molecular biology techniques that have unmasked recurrent genetic abnormalities linked to eosinophilia, and (2) the successful application of targeted therapy with agents such as imatinib to treat eosinophilic diseases. To date, most of these recurrent molecular abnormalities have resulted in constitutively activated fusion tyrosine kinases whose phenotypic consequence is an eosinophilia-associated myeloid disorder. Most notable among these are rearrangements of platelet-derived growth factor receptors alpha and beta (PDGFRalpha, PDGFRbeta), which define a small subset of patients with eosinophilic chronic myeloproliferative disorders (MPDs) and/or overlap myelodysplastic syndrome/MPD syndromes, including chronic myelomonocytic leukemia. Discovery of the cryptic FIP1L1-PDGFRA gene fusion in cytogenetically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES has redefined these diseases as clonal eosinophilias. A growing list of fibroblast growth factor receptor 1 fusion partners has similarly emerged in the 8p11 myeloproliferative syndromes, which are often characterized by elevated eosinophil counts. Herein the focus is on the molecular gains made in these MPD-type eosinophilias, and the classification and clinicopathological issues related to hypereosinophilic syndromes, including the lymphocyte variant. Success in establishing the molecular basis of a group of once seemingly heterogeneous diseases has now the laid the foundation for establishing a semi-molecular classification scheme of eosinophilic disorders.
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PMID:Molecular classification and pathogenesis of eosinophilic disorders: 2005 update. 1599 22

Idiopathic hypereosinophilic syndrome is a heterogenous group of hematological disorders characterized by eosinophilia (> 1.5 x 10(9)/l) persistent for more than 6 months, exclusion of reactive eosinophilia from other causes, such as parasitic infections or allergy, and evidence of end-organ damage. According to World Health Organization the exclusion includes all neoplastic disorders in which eosinophils are part of the neoplastic clone. Excluded should be also T cell population with aberant phenotype and abnormal cytokine production, recently considert also as "lymphocytic" variants of the HES [42]. HES has to be reclassified as chronic eosinophilic leukemia (CEL) when there is evidence for clonality based on the presence of chromosomal abnormalities or inactivation of X-chromosome in female patients. The successful empiric treatment of patients with tyrosine kinase inhibitor imatinib (Glivec) suggested the presence of an imatinib-sensitive tyrosine kinase inhibitor. The identification of a specific intersticial chromosome deletion del(4)(q12;q12) creating the FIP1L1-PDGFRA fusion gene confirmed this hypothesis. Patients carrying this gene should be reclassified as CEL and detection of this gene is a positive predictor for response to imatinib therapy. Effective doses of imatinib are 100 mg/day. The side effects are minimal. The only exception is an acute left ventricular dysfunction which has been reported in three patients within the first week of treatment with imatinib. Imatinib has been successfully used also in some patients with the constitutively activated thyrosine kinase ETV6-PDGFRbeta [1] and in systemic mast cell disease associated with eosinophilia. Other therapeutical options for HES/CEL have been mentioned. The resistence to imatinib and the possibilities how to overcome it are discussed.
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PMID:[The idiopathic hypereosinophilic syndrome and chronic eosinophilic leukemia]. 1643 Jan 6

Systemic mast cell disorders in most instances appear to be clonal disorders of the mast cell and its progenitor. Symptoms result from a pathological release of mast cell mediators and a destructive mast cell infiltration. Cutaneous mastocytosis is most frequently seen in children and may regress. Systemic mastocytosis (SM) is a persistent disease. A somatic c-kit mutation at codon 816 is often detectable in haematopoietic cells. The clinical course of mastocytosis is variable, ranging from indolent to aggressive. Five categories of disease are recognized: Indolent SM, aggressive SM, SM with associated clonal haematological non-mast cell-lineage disease (AHNMD) and mast cell leukaemia (MCL). In SM-AHNMD, additional genetic abnormalities have been reported. Patients with cutaneous or indolent systemic disease are treated symptomatically. Patients with aggressive disease are candidates for cytoreductive therapy. The use of 'Kit-targeting' tyrosine kinase inhibitors are best selected following a mutational analysis of c-kit. For instance, the D816V mutation appears to be associated with relative resistance against imatinib. However, imatinib has been used with success in patients with SM-hypereosinophilic syndrome (HES) and the FIPL1/PDGFRA fusion gene and in a patient with mastocytosis with a mutation outside of codon 816. The value of bone marrow transplantation remains under investigation.
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PMID:Mastocytosis. 1660 39

Before the 1990s, lack of evidence for a reactive cause of hypereosinophilia or chronic eosinophilic leukemia (e.g. presence of a clonal cytogenetic abnormality or increased blood or bone marrow blasts) resulted in diagnosticians characterizing such nebulous cases as 'idiopathic hypereosinophilic syndrome (HES)'. However, over the last decade, significant advances in our understanding of the molecular pathophysiology of eosinophilic disorders have shifted an increasing proportion of cases from this idiopathic HES 'pool' to genetically defined eosinophilic diseases with recurrent molecular abnormalities. The majority of these genetic lesions result in constitutively activated fusion tyrosine kinases, the phenotypic consequence of which is an eosinophilia-associated myeloid disorder. Most notable among these is the recent discovery of the cryptic FIP1L1-PDGFRA gene fusion in karyotypically normal patients with systemic mast cell disease with eosinophilia or idiopathic HES, redefining these diseases as clonal eosinophilias. Rearrangements involving PDGFRA and PDGFRB in eosinophilic chronic myeloproliferative disorders, and of fibroblast growth factor receptor 1 (FGFR1) in the 8p11 stem cell myeloproliferative syndrome constitute additional examples of specific genetic alterations linked to clonal eosinophilia. The identification of populations of aberrant T-lymphocytes secreting eosinophilopoietic cytokines such as interleukin-5 establish a pathophysiologic basis for cases of lymphocyte-mediated hypereosinophilia. This recent revival in understanding the biologic basis of eosinophilic disorders has permitted more genetic specificity in the classification of these diseases, and has translated into successful therapeutic approaches with targeted agents such as imatinib mesylate and recombinant anti-IL-5 antibody.
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PMID:Eosinophilic disorders: molecular pathogenesis, new classification, and modern therapy. 1678 88

Systemic mastocytosis (SM) is characterized by the abnormal growth and accumulation of mast cells (MC) in one or more organs. The interaction between the cytokine stem cell factor (SCF) and its cognate receptor, the c-kit receptor tyrosine kinase (KIT), plays a central role in regulating MC growth and differentiation. Whereas germline and somatically acquired activating mutations of KIT have been identified in SM, the issue as to whether individual KIT mutation(s) are necessary and sufficient to cause MC transformation remains unclear based on currently available data. Activating mutations of platelet-derived growth factor receptor-alpha (FIP1 L1-PDGFRA) are identified in a significant number of SM cases that have associated eosinophilia. To date, as with gastrointestinal stromal tumors, activating mutations of KIT and PDGFRA appear to be alternative and mutually exclusive genetic events in SM. The World Health Organization has specified criteria for classification of SM into six major subtypes: cutaneous mastocytosis, indolent systemic mastocytosis (ISM), systemic mastocytosis with an associated clonal hematological non-mast-cell disorder (SM-AHNMD), aggressive systemic mastocytosis (ASM), mast cell leukemia, and mast cell sarcoma. The ability to molecularly classify individual SM cases based on the presence or absence of specific mutations allows for molecularly targeted therapy in a growing number of cases. Imatinib mesylate therapy might result in complete remission of SM cases with wild-type KIT, certain KIT mutations, such as F522C, or the FIP1L1-PDGFRA fusion gene, but not of D816V-KIT-bearing SM. For the latter, interferon-alpha and 2-CdA are potential first- and second-line therapeutic options. Other drugs under investigation include novel tyrosine kinase inhibitors, as well as NF-kappaB inhibitors, which might display greater selectivity towards D816V-KIT as compared to wild type KIT. The pathogenesis of mastocytosis, its major clinical subtypes, and recent treatment advances are discussed in this chapter.
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PMID:Pathogenesis, clinical features, and treatment advances in mastocytosis. 1678 90

Serum (or plasma) levels of total and mature tryptase measurements are recommended in the diagnostic evaluation of systemic anaphylaxis and systemic mastocytosis, but their interpretation must be considered in the context of a complete workup of each patient. Total tryptase levels generally reflect the increased burden of mast cells in patients with all forms of systemic mastocytosis (indolent systemic mastocytosis, smoldering systemic mastocytosis, systemic mastocytosis associated with a hematologic clonal non-mast cell disorder, aggressive systemic mastocytosis, and mast cell leukemia) and the decreased burden of mast cells associated with cytoreductive therapies in these disorders. Causes of an elevated total tryptase level other than systemic mastocytosis must be considered, however, and include systemic anaphylaxis, acute myelocytic leukemia, various myelodysplastic syndromes, hypereosinophilic syndrome associated with the FLP1L1-PDGFRA mutation, end-stage renal failure, and treatment of onchocerciasis. Mature (beta) tryptase levels generally reflect the magnitude of mast cell activation and are elevated during most cases of systemic anaphylaxis, particularly with parenteral exposure to the inciting agent.
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PMID:Diagnostic value of tryptase in anaphylaxis and mastocytosis. 1693 Dec 88

In this study, 60 gastrointestinal stromal tumors of the stomach were analyzed to elucidate the possible relation of their morphology to the mutation status of KIT and PDGFRA genes. The patients included 27 men and 33 women with a mean age of 63.8 years (range, 12-92 years). Only 1 tumor occurred before the age of 21 years. KIT mutations were detected in 31 cases (51.7%), PDGFRA mutations in 22 cases (36.7%), and 7 cases (11.7%) were KIT and PDGFRA wild type. When the mutation status was correlated with histologic features of the tumors, epithelioid or mixed epithelioid/spindle cell pattern and mast cell infiltration were found as the most reliable signs of PDGFRA mutation. Neoplastic rhabdoid cells and multinucleated giant cells, also previously reported as features of PDGFRA-mutated gastrointestinal stromal tumors, seemed to be less specific but still helpful markers in our study. Finally, tumor-infiltrating lymphocytes and myxoid stroma do not seem to be valuable histologic signs.
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PMID:Diagnostic morphological features of PDGFRA-mutated gastrointestinal stromal tumors: molecular genetic and histologic analysis of 60 cases of gastric gastrointestinal stromal tumors. 1724 Mar 4

Several reports of successful empirical treatment of idiopathic hypereosinophilic syndrome with imatinib led to the recent identification of the FIP1L1-PDGFRA fusion gene rearrangement, which characterizes a distinctive group of chronic eosinophilic leukemias. This fusion gene can be detected in eosinophils, neutrophils, mast cells, T cells, B cells and monocytes in FIP1L1-PDGFRA-positive hypereosinophilic patients suggesting a multilineage involvement. Furthermore, the same FIP1L1-PDGFRA rearrangement was identified in patients with hypereosinophilia and atypical mast cell proliferations, raising the question of a disease with two concomitant lines of differentiation. In addition, a recent report noted two cases with the association of FIP1L1-PDGFRA-positive chronic eosinophilic leukemia and T-cell lymphoblastic lymphoma (T-LBL). We report here the only third case of synchronous chronic eosinophilic leukemia and T-LBL, both associated with a FIP1L1-PDGFRA fusion transcript, confirming the occurrence of such disease and suggesting a clonal proliferation with two lines of differentiation probably arising from a primitive multipotent medullary stem cell.
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PMID:Synchronous FIP1L1-PDGFRA-positive chronic eosinophilic leukemia and T-cell lymphoblastic lymphoma: a bilineal clonal malignancy. 1802 20

Eosinophilia is a recurrent feature and diagnostic clue in several hematologic malignancies. In stem cell- and myelopoietic neoplasms, eosinophils are derived from the malignant clone, whereas in lymphoid neoplasms and reactive states, eosinophilia is usually triggered by eosinopoietic cytokines. Myeloid neoplasms typically presenting with eosinophilia include chronic myeloid leukemia, chronic eosinophilic leukemia (CEL), other myeloproliferative neoplasms, some acute leukemias, advanced mast cell disorders, and rare forms of myelodysplastic syndromes. Diagnostic evaluations in unexplained eosinophilia have to take these diagnoses into account. In such patients, a thorough hematologic work-up including bone marrow histology and immunohistochemistry, cytogenetics, molecular markers, and a complete staging of potentially affected organ systems has to be initiated. Endomyocardial fibrosis, the most dangerous cardiovascular complication of the hypereosinophilic state, is frequently detected in PDGFR-mutated neoplasms, specifically in FIP1L1/PDGFRA+ CEL, but is usually not seen in other myeloid neoplasms or reactive eosinophilia, even if eosinophilia is recorded for many years. Treatment of hypereosinophilic patients depends on the variant of disease, presence of end organ damage, molecular targets, and the overall situation in each case. In a group of patients, oncogenic tyrosine kinases (TK) such as FIP1L1/PDGFRA, can be employed as therapeutic targets by using imatinib or other TK-blocking agents.
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PMID:Pathogenesis, classification, and therapy of eosinophilia and eosinophil disorders. 1924 39


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