Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe the case of a 69-year-old man with systemic mastocytosis and severe osteopetrosis who carries a somatic activating mutation in the c-kit proto-oncogene. The patient initially presented with urticaria pigmentosa, progressing to systemic mast cell disease with severe anemia due to bone marrow involvement, chronic diarrhea, and hepatosplenomegaly. Direct sequencing using amplimers from reverse transcriptase-polymerase chain reactions (RT-PCR) from skin mast cell-derived RNA revealed a point mutation in the c-kit proto-oncogene at position 2468, introducing a new recognition site for the restriction endonuclease HinfI. Treatment with interferon-alpha 2a, prednisone, and erythropoietin was initiated. Subsequently, clinical symptoms improved significantly and hemoglobin levels are now stable at 13 g/dl.
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PMID:c-kit mutation and osteopetrosis-like osteopathy in a patient with systemic mast cell disease. 979 83

We report a case of gastrointestinal stromal tumor (GIST) with multiple hepatic metastases that responded to tyrosine kinase inhibitor STI571. A 30-year-old woman underwent total gastrectomy on July 10, 1998, with a diagnosis of submucosal tumor of the stomach. Pathological analysis of the primary lesion revealed strong expression of c-kit, and it was diagnosed as GIST. The patient underwent tumor excision due to peritoneal recurrence on May 1, 2000 and November 13, 2000. On August 8, 2001, multiple liver metastases were detected by abdominal CAT scan. Treatment with STI571 at a dose of 400 mg/day for 28 days was initiated on September 14, 2000. CAT scan showed rapid tumor shrinkage after 3 weeks of treatment (reduction rate of 56%) and the response continued after 7 weeks of treatment (reduction rate of 71%). Thus, we evaluated the response as PR. Leukocytopenia, edema, diarrhea and nausea were observed; however, all toxicities were mild and tolerable. This case suggests the efficacy of STI571 for metastatic GIST.
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PMID:[A patient with metastatic gastrointestinal stromal tumor who responded to STI571]. 1197 48

Gastrointestinal allergic disorders represent a diverse spectrum of inflammatory diseases that are occurring with increasing incidence and severity. An essential question concerning these disorders is to determine the specific cells and mediators responsible for specific clinical manifestations. With this in mind, we developed a murine model of oral allergen-induced intestinal inflammation accompanied by strong Th2-associated humoral and cellular responses and focused on the immunopathogenesis of allergic diarrhea. Exposure of OVA/alum-sensitized mice to repeated doses of intragastric OVA induced genetically restricted, dose-dependent, acute diarrhea associated with increased intestinal permeability, eosinophilia, and mastocytosis. Mice developed limited systemic manifestations of anaphylaxis, even though they developed marked intestinal mucosal mast cell degranulation. Notably, experiments involving mast cell depletion (with anti-c-kit mAb), anti-IgE treatment, and Fc epsilon RI-deficient mice indicated a critical effector role for mast cells in mediating allergic diarrhea. Furthermore, allergic diarrhea was dependent upon synergistic signaling induced by serotonin and platelet-activating factor (PAF), but not histamine. These results demonstrate that oral allergen-induced diarrhea associated with experimental Th2 intestinal inflammation is largely mast cell, IgE, serotonin, and PAF dependent.
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PMID:Mast cells are required for experimental oral allergen-induced diarrhea. 1466 Jul 43

Mastocytosis comprises several diseases characterized by an abnormal increase in tissue mast cells. Cutaneous mastocytosis (CM) is the most common form of mastocytosis, affects predominantly children, and presents as a mast cell hyperplasia limited to the skin. Systemic mastocytosis (SM) comprises multiple distinct entities in which mast cells in filtrate the skin and/or other organs. The diagnosis of SM is based on the presence of one major criterion and one minor criterion or three minor criteria. Major criteria include the presence of multifocal dense infiltrates of > 15 mast cells in bone marrow and/or other extracutaneous organs. Four minor criteria include the presence of elevated serum alpha-tryptase levels > 20 ng/mL, the expression of CD2 and CD25 surface markers in c-kit-positive mast cells from bone marrow or other organs, the presence of a c-kit mutations on bone marrow and/or other tissues mast cells, and the presence of > 25% abnormal spindle-shaped mast cells in bone marrow and/or tissues. Symptoms of CM include pruritus, flushing urticaria, and dermatographism. Symptoms of SM include cutaneous symptoms in association with syncope, gastric distress, nausea and vomiting, diarrhea, bone pain, and neuropsychiatric symptoms. Activating and nonactivating mutations of c-kit (Asp816Val) are seen in adult SM and in some pediatric CM (Gly839Lys), indicating a clonal dysregulation. There is no cure for mastocytosis but the majority of pediatric CM regress at puberty. Women with mastocytosis are fertile and pregnancy and delivery have been successful by blocking mast cell-mediated symptoms. Symptomatic treatment aimed at reducing the effect of mediators is effective with antihistamines and mast cell-stabilizing agents such as sodium cromolyn. To reduce mast cell burden, interferon alpha, steroids, and purine analogs have been used with varying results. Future directions include tyrosine kinase inhibitors and bone marrow transplant.
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PMID:Mastocytosis: classification, diagnosis, and clinical presentation. 1505 60

In mast cell (MC) disorders (mastocytosis), clinical symptoms are caused by the release of chemical mediators from MCs, the pathologic infiltration of neoplastic MCs in tissues, or both. Cutaneous mastocytosis is a benign disease in which MC infiltration is confined to the skin. In pediatric cases cutaneous mastocytosis might regress spontaneously. Systemic mastocytosis (SM) is more frequently diagnosed in adults and is a persistent (clonal) disease of bone marrow-derived myelomastocytic progenitors. The somatic c-kit mutation D816V is found in the majority of such patients. The natural clinical course in SM is variable. Whereas most patients remain at the indolent stage for many years, some have aggressive SM (ASM) at diagnosis. Other patients have an associated clonal hematologic non-MC lineage disease (AHNMD). MC leukemia (MCL) is a rare disease variant characterized by circulating MCs and fatal disease progression. The diagnoses of ASM, SM-AHNMD, and MCL might be confused with a variety of endocrinologic, vascular, or immunologic disorders. It is therefore of particular importance to be aware of the possibility of an underlying (malignant) MC disease in patients with unexplained vascular instability, unexplained (anaphylactoid) shock, idiopathic flushing, diarrhea, headache, and other symptoms that might be mediator related. An important diagnostic clue in such cases is an increased serum tryptase level. The current review provides an overview of mastocytosis and its subvariants and a practical guide that might help to delineate mastocytosis from unrelated systemic disorders.
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PMID:Diagnosis and classification of mast cell proliferative disorders: delineation from immunologic diseases and non-mast cell hematopoietic neoplasms. 1524 37

Gastrointestinal stromal tumor (GIST), the most common mesenchymal tumor of the human gastrointestinal tract, is thought to originate from the interstitial cells of Cajal. The mutation of c-kit, cording KIT, is essential in the development of GIST. Imatinib mesylate (IM), an agent for chronic myeloid leukemia, was reported to inhibit tyrosine kinase activity of KIT and to be highly effective for GIST. We report, here, a case of huge gastric GIST who underwent neoadjuvant therapy followed by surgical resection. The patient was a 62-year-old man with GIST in cardia (KIT+, CD34+, mitotic rate 5/50 HPF), whose chief complaint was general fatigue. Because the huge tumor, 7.5 cm in size, directly invaded the pancreas, total gastrectomy with distal pancreatosplenectomy was necessary for curative resection. IM was administered (400 mg/body/day) as a neoadjuvant treatment for down-staging of the tumor. Leucopenia (grade 2) and diarrhea (grade 1) were observed as the adverse effects of IM. Partial response was obtained. He underwent proximal gastrectomy without pancreatosplenectomy since CT no longer showed direct invasion to the pancreas. Histological examination of the resected specimen revealed the extensive degeneration of the tumor, in which tumor cells containing condensed nuclei had decreased remarkably. Interestingly, mitotic rate decreased to 0/50 HPF in the effective area of the resected specimen, indicating that recurrent risk might be decreased. A part of the viable tumor cells, however, had the same feature to that in the biopsied specimen before treatment. The results suggest that the heterogeneity of GIST induces different sensitivity to IM. The postoperative course was uneventful and no sign of recurrence was observed 3 months after surgery. Neoadjuvant therapy with IM may become a useful strategy for GIST, as it reduces the tumor size and decreases the recurrence rate.
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PMID:[A case of gastric GIST treated preoperatively by imatinib mesylate]. 1533 47

BAY 43-9006 is an oral inhibitor of CRAF, wild-type BRAF, mutant V599E BRAF, vascular endothelial growth factor receptor (VEGFR) 2, VEGFR3, mVEGFR2, FLT-3, platelet-derived growth factor receptor, p38, and c-kit among other kinases. A Phase I study of BAY 43-9006 identified 400 mg orally twice daily as the recommended Phase II dose. The Phase II results of a study of BAY 43-9006 at 400 mg orally twice daily were particularly interesting in patients with renal cell carcinoma. Data from the first 41 patients with renal cell carcinoma showed that 30% of patients had stable disease (defined as between 25% reduction and 25% growth), 40% had responded (defined as >25% reduction), and 30% had progressed. Disease could be stabilized for periods in excess of a year. Some lesions became cystic and could actually enlarge while developing a low attenuation core. This phenomenon is recognized in the treatment of gastrointestinal stromal tumors with imatinib mesylate. The toxic effects of BAY 43-9006 were manageable and included hypertension, edema, diarrhea, hand and foot syndrome, rash, and hair loss where the rash involved the scalp. There was an impression of tachyphylaxis such that patients who required a dose reduction could be restored to full dose after a few months. A Phase III randomized, placebo-controlled trial of BAY 43-9006 has started for patients whose renal cell carcinoma has progressed within 6 months of immunotherapy. Combination studies with interferon, interleukin 2, bevacizumab, and chemotherapy are under consideration. The therapeutic targets of BAY 43-9006 in renal cell carcinoma remain unclear. Unlike melanoma, BRAF mutations have not been found in renal cell carcinoma. Other candidate targets include VEGFR2 and VEGFR3.
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PMID:Kinase inhibition with BAY 43-9006 in renal cell carcinoma. 1544 36

PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.
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PMID:Phase 1 study of PTK787/ZK 222584, a small molecule tyrosine kinase receptor inhibitor, for the treatment of acute myeloid leukemia and myelodysplastic syndrome. 1661 23

A 46-year-old woman was admitted to the hospital with complaints of chronic diarrhoea, vomiting and severe muscle weakness. Clinical examination showed a lethargic, malnourished, dehydrated patient with ascites and bilateral leg oedema. Laboratory evaluation revealed mild normochromic normocytic anaemia and severe hypoproteinaemia with hypoalbuminaemia. Upper gastrointestinal endoscopy showed a thickened, friable duodenal mucosa with multiple erosions. Colonoscopy revealed nodular, pseudopolypoid lesions with patchy erosions in the left hemicolon. Haematoxylin-eosin stained sections from biopsies of endoscopically abnormal bowel segments showed multi-focal aggregates of large, histiocyte-like cells with abundant pale cytoplasm in the lamina propria. These cells were negative on PAS, Ziehl-Neelsen, Giemsa and toluidine blue stains. Their immunophenotype was CD68 (+), c-kit/CD117 (+) and mast cell tryptase (+), which is consistent with mast cells. A trephine biopsy showed diffuse replacement of the bone marrow by atypical, monomorphic, frequently spindle-shaped mast cells. No associated haematopoietic malignancy was detected. The final diagnosis was aggressive systemic mastocytosis with involvement of the gastrointestinal tract complicated by protein-losing enteropathy. This association has not been reported previously. The patient has been treated with prednisolone and interferon-alpha and has since recovered.
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PMID:Aggressive systemic mastocytosis complicated by protein-losing enteropathy. 1684 41

Immunohistochemical staining is useful in the diagnosis of bone marrow infiltration in systemic mastocytosis. However, it is not clear if antibody staining may be helpful in the diagnosis of cutaneous mastocytosis (CM). We studied the histological appearance of CM in 35 pediatric patients. Cases were assigned to three basic clinical groups: I--Urticaria pigmentosa (UP, n=29); II--Mastocytomas (n=4); and III--Diffuse Cutaneous Mastocytosis (DCM, n=2). The analysis of clinical information revealed an association between the presence of diarrhea and a higher number of cells/field. Nine doubtful cases, all of them macules, were selected based on the scarcity of mast cells (MC) and the absence or rarity of other inflammatory cells. We compared the number of cells identified in Giemsa and immunohistochemical stains in definite and doubtful cases. The intraclass correlation statistic tested the concordance between each staining method. All 9 dubious cases according to the Giemsa stain had their CM diagnosis confirmed by the immunohistochemistry analysis. The intraclass correlation between Giemsa and c-kit was good (0.7) when the number of MC was high. However, there was no correlation between the mast cells counts in the two different stains in the dubious cases. The immunohistochemistry with c-kit might make CM diagnosis easier, especially in the macular cases, when there is a lower number of MC.
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PMID:Mastocytosis in children: clinicopathological study based on 35 cases. 1733 Aug 8


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