Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The goal of this study was to investigate the association of mutations in the KIT gene and the platelet-derived growth factor receptor alpha (PDGFRA) gene with clinicopathological features of patients with gastrointestinal stromal tumor (GIST) localized in the stomach. We evaluated 56 gastric GISTs for KIT and PDGFRA mutations. DNA was extracted from paraffin-embedded tumor specimens, and exons 9, 11, 13 and 17 of the KIT gene and exons 12 and 18 of the PDGFRA gene were amplified by polymerase chain reaction and sequenced. The genetic features were then compared with the clinicopathological features. Immunohistochemistry was performed for KIT, CD34, Ki-67 (as a marker of cell proliferation) and CD31 (as a marker of microvessel density), and apoptosis was assessed by in situ DNA nick-end labeling. Thirty-four (61%) of the 56 GISTs had a mutation in exon 11 of KIT, and 2 (4%) had a mutation in exon 13 of KIT. Deletions in exon 11 of KIT were the most common mutation encountered in the present study. No mutations were found in exon 9 or 17 of KIT. Six of the 20 GISTs lacking KIT mutations had a mutation in exon 18 of PDGFRA, and 1 had a mutation in exon 12 of PDGFRA. The KIT mutation-positive GISTs showed more frequent liver metastases and higher mortality than KIT mutation-negative GISTs. Our data indicate that KIT mutations, especially deletions in exon 11, are markers of poor prognosis for gastric GISTs.
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PMID:Deletion of the KIT gene is associated with liver metastasis and poor prognosis in patients with gastrointestinal stromal tumor in the stomach. 1668 37

Gastrointestinal stromal tumours (GISTs) are the most common primary mesenchymal tumours of the gastrointestinal tract. Most of them show activating mutations of the genes coding for KIT or platelet-derived growth factor receptor alpha (PDGFRalpha), two receptor tyrosine kinases (RTKs). The RTK inhibitor Imatinib (Gleevec, Novartis, Switzerland), induces regression of the tumour. The level of response to treatment, together with other clinicopathological parameters is related to the type and site of the activating mutation, thus suggesting that these tumours should be classified according to the molecular context. This is confirmed also by the phenomenon of the resistance to treatment, which arises because of different mechanisms (second mutation, amplification, activation of other RTKs) and can be fought only by specific RTK inhibitors, that are at present under development. RTK activation involves an homogeneous transduction pathway whose components (MAPK, AKT, PI3K, mTOR and RAS) are possible targets of new molecular treatment. A new paradigm of classification integrating the classic pathological criteria with the molecular changes will permit personalised prognosis and treatment.
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PMID:An update on molecular genetics of gastrointestinal stromal tumours. 1673 99

For the last 2 years, a 55-year-old man had painful, recurrent oral ulcers. Histological examination showed non-specific inflammation. Eosinophilia in the blood and bone marrow raised the suspicion of hypereosinophilic syndrome. No other specific organ involvement was observed. The diagnosis was confirmed by detection of the fusion gene 'FIP1-like-1-platelet-derived growth factor receptor alpha' (FIP1L1-PDGFRA) in the peripheral blood and bone marrow. Treatment with the tyrosine-kinase inhibitor imatinib resulted in a rapid response that has been maintained for more than 2 years. Hypereosinophilic syndrome is a rare haematological disorder. Until recently diagnosis was made by exclusion, and the course of disease was often fatal. Fusion of the FIP1L1 gene to the PDGFRA gene was identified recently in some patients with hypereosinophilic syndrome. The fusion results in a novel tyrosine kinase that is constitutively activated and may induce proliferation ofhaematopoietic cells. Treatment with imatinib targets this tyrosine kinase. These advances in our understanding of the molecular biology of the disease will lead to a new classification of hypereosinophilic syndrome with specific therapeutic options.
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PMID:[A man with oral ulcers caused by hypereosinophilic syndrome and a good response to the tyrosine-kinase inhibitor imatinib]. 1676 85

Persistent eosinophilia was diagnosed in a 19-year-old woman with general malaise, dyspnoea attacks, coughing and episodes of angioedema and associated swallowing problems, and in a 21-year-old man with visual problems, dyspnoea, fatigue, reduced appetite, weight loss and gastrointestinal problems. Both had hypereosinophilic syndrome (a rare disease) with organ damage. In both patients, fluorescence-in-situ-hybridisation (FISH) was negative for the fusion gene FIP1L1-PDGFRA (FIPI-like-1-platelet-derived growth factor receptor alpha). The female patient's disease did not respond to either oral corticosteroids or imatinib, but did respond to hydroxycarbamide. The male patient successively received prednisone, interferon alpha and hydroxycarbamide. His eosinophilia progressed nonetheless, but responded partially to imatinib. In addition, the patient underwent an allogenic non-myeloblative stem cell transplantation from his HLA-identical sister. In patients with persistent eosinophilia accompanied by organ damage or organ dysfunction, hypereosinophilic syndrome can be diagnosed providing all secondary causes of the eosinophilia have been ruled out. Complementary investigations should include cytogenetic and clonal analysis to rule out haemopoietic malignancy. Prednisone, hydroxycarbamide, interferon alpha and the promising imatinib are all treatment options.
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PMID:[Two patients with hypereosinophilic syndrome]. 1676 84

Imatinib mesylate is a specific inhibitor of the Bcr-Abl protein tyrosine kinase that competes with ATP for its specific binding site in the kinase domain. It has activity against platelet-derived growth factor receptor alpha and beta (PDGFR-alpha and -beta), and c-kit, the receptor for stem cell factor. We have used a standardized ATP-tumor chemosensitivity assay and immunohistochemistry to determine the cytotoxicity of imatinib mesylate in tumor-derived cells from cutaneous and uveal melanoma, and ovarian carcinoma. Imatinib mesylate was tested at concentrations ranging from 2.0 to 0.0625 micromol/l alone and in combination with a cytotoxic drug (cisplatin, doxorubicin, paclitaxel or treosulfan). Imatinib mesylate showed low inhibition (IndexSUM>300) across the range of concentrations tested in this study, with few tumors exhibiting increasing inhibition with increased drug concentration. The median IC90 values for cutaneous and uveal melanoma and ovarian carcinoma were 13.2 micromol/l (4.0-294.3 micromol/l), 12.0 micromol/l (2.0-285.4 micromol/l) and 7.71 micromol/l (6.51-11.02 micromol/l), respectively. Imatinib mesylate potentiated the effect of different cytotoxics in 9% (5/54) of cases and had a negative effect in 13% (7/54) of cases, with no effect in the remainder. No correlation of effect was noted with c-kit, platelet-derived growth factor receptor-alpha or platelet-derived growth factor receptor-beta expression, assessed by immunohistochemistry. The signaling pathways mediated by activation of c-kit or platelet-derived growth factor receptor may act as antiapoptotic survival signals in some cancers and inhibition of these pathways may potentiate the activity of some cytotoxic drugs by inhibiting the survival signal. Growth inhibition, however, may reduce the efficacy of cytotoxic drugs, which tend to target proliferating cells preferentially, and clinical effects are therefore difficult to predict.
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PMID:The effect of imatinib mesylate (Glivec) on human tumor-derived cells. 1691 10

Idiopathic hypereosinophilic syndrome (IHES) is a rare disorder affecting cardiac, pulmonary and nervous systems with peripheral neuropathy, encephalopathy and cerebral thromboembolism. We report a 7-year-old boy with IHES who developed central sinovenous thrombosis and cerebral hemorrhage. Although he had hypereosinophilia for more than 6 months, he was asymptomatic until the sudden onset of vomiting and headache due to superior sagittal sinus thrombosis. Molecular analysis in peripheral blood did not reveal any mutation in the Fip1-like-platelet-derived growth factor receptor alpha chain (FIP1L1-PDGFRA) gene which was recently reported to be mutated in IHES. Since there must be symptoms or signs of organ involvement to fulfill the IHES criteria, we could not make a diagnosis of IHES until the onset of central nervous system involvement. We suggest that anti-coagulant therapy should be considered for asymptomatic patients with hypereosinophilia because hypereosinophilia may induce thrombosis in various organs.
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PMID:Idiopathic hypereosinophilic syndrome complicated by central sinovenous thrombosis. 1699 10

A 39-year-old man was referred from Surinam to the Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands, for a right ventricular tumour, hypereosinophilia and mild thrombocytopenia. He appeared to have chronic eosinophilic leukaemia that was positive for the 'FIP1-like-1-platelet-derived growth factor receptor alpha' (FIP1L1-PDGFRA) gene. In addition, he had signs of a right ventricular thrombus that had existed for at least 6 months. The patient was treated with oral anticoagulants and the tyrosine kinase inhibitor imatinib. The latter therapy resulted in normalisation of leukocyte count and differential values. After 3 months of therapy, the FIP1L1-PDGFRA fusion transcript was no longer detectable in peripheral blood. After 1 year of follow up, the patient was in complete haematological and molecular remission for chronic eosinophilic leukaemia. The cardiac mass remained unchanged, but caused no haemodynamic problems.
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PMID:[A man with FIP1L1/PDGFRA-positive chronic eosinophilic leukemia]. 1699 79

The Carney triad is a rare syndrome of unknown aetiology, with synchronous or metachronous appearance of rare neoplasms: gastrointestinal stromal tumours (GISTs), pulmonary chondromas and extra-adrenal paragangliomas. In most cases, the Carney triad is incomplete. The combination encountered typically, GISTs and pulmonary chondromas, was also seen in our patient, a 22-year-old woman. She was diagnosed with the triad after Billroth II gastrectomy for histologically proved gastric GISTs. The diagnosis of pulmonary chondromas was confirmed by transthoracic, computed tomography-guided needle biopsy. An oesophageal leiomyoma was resected 2 years after the initial diagnosis, on suspicion of paraganglioma. The clinical course of the patient has been uneventful since. The last follow-up was carried out 6 years after the initial diagnosis. On histological examination, the cells of gastric GIST were partly positive for CD34, whereas CD117 was expressed in all areas in variable intensity and S-100 protein was negative. The oesophageal tumour was classified as leiomyoma due to strong immunopositivity for smooth muscle actin and desmin, being negative for CD34 and CD117. Two different gastric GIST lesions as well as the oesophageal leiomyoma and normal tissue were analysed for activating mutations in common hot spots of KIT (exon 9 and 11) and platelet-derived growth factor receptor alpha (exon 18), but in all probes wild-type sequences were found. These results are in accordance with the first published analyses of GIST lesions from Carney patients.
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PMID:A new case of Carney triad: gastrointestinal stromal tumours and leiomyoma of the oesophagus do not show activating mutations of KIT and platelet-derived growth factor receptor alpha. 1702 Nov 35

The goal of this study was to investigate differences in the clinicopathologic and genetic characteristics of gastric and extragastric gastrointestinal stromal tumors (GISTs). We evaluated 13 extragastric GISTs and compared them with 56 gastric GISTs, which were described previously. DNA was extracted from paraffin-embedded tumor specimens, and exons 9, 11, 13, and 17 of the KIT gene and exons 12 and 18 of the platelet-derived growth factor receptor alpha (PDGFRA) gene were amplified by polymerase chain reaction and sequenced. Immunohistochemistry was performed for KIT, CD34, Ki-67 (as a marker of cell proliferation), and CD31 (as a marker of microvessel density), and apoptosis was assessed by in situ DNA nick end-labeling. Of the 13 extragastric GISTs 7 (54%) had a mutation in exon 11 of KIT, and 2 (15%) had a mutation in exon 13 of KIT. Deletions in exon 11 of KIT were the most common mutation encountered in the extragastric GISTs. The extragastric GISTs, especially small intestinal GISTs, showed larger deletions, leading to deletions of amino acid residues in the KIT protein, and higher vascularity than did the gastric GISTs. These data suggest that extragastric GISTs differ from gastric GISTs with respect to associated mutations and angiogenic activity.
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PMID:Genetic and pathologic characteristics of gastrointestinal stromal tumors in extragastric lesions. 1708 9

Cytogenetic discoveries of balanced translocations in soft tissue tumors have opened the way to molecular genetic definition of these translocations as gene fusions from the late 1980s. Many sarcomas are known to have such fusions, and the demonstration of the fusion transcripts in tumor tissue is of great value in specific diagnosis of synovial sarcoma (SYT-SSX), Ewing sarcoma (EWS-Fli1), clear cell sarcoma (EWS-ATF1), myxoid liposarcoma (FUS-CHOP), and other sarcomas. These translocations are believed to be disease-specific and pathogenetic forces, despite occasional observations to the contrary. Demonstration of SYT-SSX and EWS-ATF1 fusion assists in the diagnosis of synovial and clear cell sarcomas in unusual locations, such as the gastrointestinal tract, where these tumors occur with low frequency. Demonstration of sarcoma translocations and their fusion by different assays is well established; use of in situ hybridization is limited by availability of specific probes. In two exceptional instances, the same translocation and gene fusion occurs in two unrelated diseases: ETV6-NTRK fusion in infantile fibrosarcoma and secretory carcinoma of the breast, and ALK-TPM3 fusion in inflammatory myofibroblastic tumor and large cell anaplastic lymphoma. Thus, the target cell of the genetic change is an important factor to define the resulting disease. Activating mutations in two related receptor tyrosine kinases (RTKs), KIT, and platelet-derived growth factor receptor alpha (PDGFRA) is central to the pathogenesis of gastrointestinal stromal tumors (GISTs), and countering the mutational activation by specific tyrosine kinase inhibitors, such as Imatinib mesylate, is now standard treatment for metastatic GISTs. KIT exon 11 mutations (in frame deletions, point mutations, and duplications) occur in GISTs of all locations, whereas a characteristic exon 9 insertion-duplication AY502-503 is nearly specific for intestinal vs gastric tumors. In contrast, PDGFRA mutations are nearly specific for gastric GISTs, especially those with epithelioid morphology. Mutation type influences therapy responsiveness, but fortunately very few GISTs carry primarily Imatinib-resistant mutations. Secondary drug resistance acquired during Imatinib treatment based on new, Imatinib-resistant mutations is a major problem limiting treatment success. Loss of NF2 tumor suppressor gene in a biallelic fashion is believed to be central in the pathogenesis of neurofibromatosis 2 (NF2) associated and sporadic schwannomas and meningiomas. The mechanism includes nonsense or missense mutation in NF2 gene, and loss of the other NF2 allele as a part of losses in chromosome 22q. Schwannoma types may differ in their pathogenesis: gastrointestinal schwannomas lack NF2 changes suggesting a different pathogenesis. Intraneural and sclerosing perineuriomas display similar NF2 gene alterations as seen in meningioma, indicating a similar pathogenesis and molecular homology. Specific viral sequences of human herpesvirus 8 (HHV8) are diagnostic markers for Kaposi sarcoma (KS), and are absent in angiosarcoma. Despite discovery on simian virus SV40 sequences in mesothelioma as a possible pathogenetic factor, recent studies suggest that the presence of these sequences may be artifactual and based on common presence of some SV40 sequences as PCR contaminants.
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PMID:From morphological to molecular diagnosis of soft tissue tumors. 1716 60


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