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)

Gastrointestinal stromal tumors (GISTs), the most common mesenchymal tumors of the intestinal tract, are characterized by the expression of KIT, also known as CD117. Increasingly, primary tumors from novel sites are being described. The KIT gene is commonly mutated, causing constitutive activation of the protein and aberrant growth. Recently, tumors with platelet-derived growth factor receptor (PDGFR)-a mutations have been described in GISTs with wild-type KIT. Factors that predict for an unfavorable outcome are being recognized. A specific molecularly targeted drug, imatinib mesylate, has altered the treatment of this disease. The results of phase I, II, and III clinical trials have consistently demonstrated activity of this agent and elucidated the patient and tumor characteristics associated with response to imatinib. The current challenge in caring for these patients is to identify the appropriate clinical setting for treatment with imatinib and to define the approach to patients whose tumors are insensitive or refractory to imatinib.
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PMID:Recent advances in the management of gastrointestinal stromal tumors. 1278 Oct 70

Gastrointestinal stromal tumor (GIST) is now defined as a specific, KIT-expressing and KIT-signaling driven mesenchymal tumor of the gastrointestinal (GI) tract. The specific identification of GIST has become more important after the availability of KIT-selective tyrosine kinase inhibitor Imatinib mesylate, STI571, commercially known as Gleevec/Glivec (Novartis Pharma, Basel, Switzerland) in the treatment of unresectable and metastatic tumors. GISTs are the most common mesenchymal neoplasms of the GI tract, and encompass most tumors previously classified as gastric and intestinal smooth muscle tumors. GISTs typically present in adults over 40 years (median age 55-60 years) and only exceptionally in children. They can present anywhere in the GI-tract from the lower esophagus to the anus. A great majority of GISTs occur in the stomach (60-70%) or small intestine (25-35%). Colon, rectum, appendix (together 5%) and esophagus (2-3%) are rare sites. Some GISTs are primary in the omentum, mesentery or retroperitoneum, unrelated to the tubular GI-tract, but most GISTs in these sites are metastases from gastric or intestinal primary. Histologically GISTs vary from cellular spindle cell tumors to epithelioid and pleomorphic ones, and morphology differs somewhat by site. By definition, GISTs are KIT(CD117)-positive. Positivity for nestin (90-100%) and CD34 (70%) are also characteristic but less specific features. Smooth muscle actins (20-30%) and heavy caldesmon (80%) are often expressed, whereas desmin is usually absent. Predictive of malignancy are mitotic rate over 5 per 50 HPF or size over 5 cm. However, mitotically inactive intestinal tumors can metastasize, and gastric tumors are in average less often malignant than the intestinal ones. True smooth muscle tumors, GI-schwannoma and undifferentiated sarcomas are the most important differential diagnoses. KIT activating mutations occur in 70-80% of cases. Their signaling consequences, clinical correlation and response to tyrosine kinase inhibitors, and specific genetic alterations are under intense investigation. Majority of these mutations are in-frame-deletions and missense mutations clustering in the 5'-end of juxtamembrane domain (exon 11). A rare mutation, an Ala502-Tyr503 duplication in exon 9, is specific for intestinal GISTs.
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PMID:Gastrointestinal stromal tumors (GISTs): definition, occurrence, pathology, differential diagnosis and molecular genetics. 1281 76

Mast cell sarcoma is an extremely rare and aggressive type of mast cell disease. Only a few cases have been described so far, and little is known about the biology and phenotype of afflicted cells. We describe morphologic and immunophenotypic properties of neoplastic mast cells in a case of an intracranial mast cell sarcoma. In Wright-Giemsa-stained cytospin preparations, the morphology of dispersed cells appeared to be highly atypical with a considerable percentage of metachromatic blasts and mast cells with bilobed or multilobed nuclei. Combined toluidine blue/immunofluorescence staining revealed expression of CD13, CD45, CD88, CD116, and CD117 (c-KIT) on neoplastic mast cells. As assessed by immunohistochemistry, mast cells were immunoreactive for tryptase and CD68R, In contrast, the CD2 antigen that is expressed in mast cells in patients with indolent systemic mastocytosis was not detectable. Mast cells also failed to display the c-KIT mutation Asp-816-Val, which is typically found in systemic mast cell disorders. Together, neoplastic mast cells in a case of mast cell sarcoma were found to exhibit unique morphologic, phenotypical, and molecular features when compared with mast cells in indolent mastocytosis or normal tissue mast cells.
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PMID:Morphologic and immunophenotypic properties of neoplastic cells in a case of mast cell sarcoma. 1282 96

Chorioangiomas are benign angiomatous tumours of the placenta occurring with a frequency of approximately one per cent of all examined placentae. Hypoxia and genetic factors are discussed to be predisposing factors for chorioangiomas. However, not much is known about the tumorigenesis of these benign tumours. Screening with various antibodies in a rare case of chorangiomatosis, we found disseminated spindle cells coexpressing vascular epithelial growth factor (VEGF), neutral endopeptidase 24.11 (NEP/CD10), and KIT protein (CD117) within the tumour stroma. A possible involvement of such factors in angiogenesis and tumorigenesis of chorioangiomas/chorangiomatosis has not been studied so far.Seven placentae with chorioangiomas (n=6) or chorangiomatosis (n=1), six normal placentae, and four cutaneous haemangiomas were analysed immunohistochemically (ABC and APAAP methods) using antibodies against VEGF, NEP, KIT protein, as well as endothelial markers like PECAM-1 (CD31), CD34, v. Willebrand factor (factor VIII), and ulex europaeus. In addition, analysis of c-kit 'gain of function' mutation Asp 816 to Val by means of Hinfl digestion and direct sequencing of semi-nested polymerase chain reaction products was performed. All chorioangiomas and haemangiomas strongly expressed the endothelial markers CD34, CD31, and FVIII, while only weak expression of ulex lectin was noted. Disseminated groups of VEGF-, NEP-, and KIT protein-positive spindle cells, which coexpressed vimentin and smooth-muscle actin were identified as myofibroblasts in the stroma of four chorioangiomas. These spindle cells were quantified as numerous in two and as rare in two other cases. No VEGF-positive myofibroblasts, however, were detected in the villous stroma of normal control placentae and haemangiomas. Only scattered perivascular myofibroblasts expressing KIT protein and NEP were detected in early gestational placenta controls. In all chorioangiomas and chorangiomatosis PCR analysis failed to unveil c-kit 'gain of function' mutation Asp 816 to Val in KIT protein-positive spindle cells. Moreover, a significant increase in mast cells was observed only in the haemangiomas. As expected, endothelial origin of chorioangiomas/chorangiomatosis was verified by CD31, CD34, FVIII expression. Myofibroblastic spindle cells expressing VEGF and NEP may be precursor cells in these peculiar angiomatous tumours. Although activating c-kit mutation Asp 816 to Val was not detected by PCR, the presence of KIT protein (CD117)-positive intratumoral myofibroblastic spindle cells in chorioangiomas and chorangiomatosis might suggest involvement of the stem cell factor (SCF)-receptor in pathologically enhanced angiogenesis.
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PMID:VEGF-, KIT protein- and neutral endopeptidase (NEP/CD10)-positive myofibroblasts-precursors of angiogenesis in chorioangiomas? 1285 66

Mesenchymal stem cells (MSCs) are typically enriched from bone marrow via isolation of the plastic adherent, fibroblastoid cell fraction. However, plastic adherent cultures elaborated from murine bone marrow are an admixture of fibroblastoid and hematopoietic cell types. Here we report a reliable method based on immunodepletion to fractionate fibroblastoid cells from hematopoietic cells within plastic adherent murine marrow cultures. The immunodepleted cells expressed the antigens Sca-1, CD29, CD44, CD81, CD106, and the stem cell marker nucleostemin (NST) but not CD11b, CD31, CD34, CD45, CD48, CD90, CD117, CD135, or the transcription factor Oct-4. They were also capable of differentiating into adipocytes, chondrocytes, and osteoblasts in vitro as well as osteoblasts/osteocytes in vivo. Therefore, immunodepletion yields a cell population devoid of hematopoietic and endothelial cells that is phenotypically and functionally equivalent to MSCs. The immunodepleted cells exhibited a population doubling time of approximately 5-7 days in culture. Poor growth was due to the dramatic down regulation of many genes involved in cell proliferation and cell cycle progression as a result of immunodepletion. Exposure of immunodepleted cells to fibroblast growth factor 2 (FGF2) but not insulin-like growth factor (IGF), murine stem cell factor, or leukemia inhibitory factor (LIF) significantly increased their growth rate. Moreover, 82% of the transcripts down regulated by immunodepletion remain unaltered in the presence of FGF2. Exposure to the later also reversibly inhibited the ability of the immunodepleted cells to differentiate into adipocytes, chondrocytes, and osteoblasts in vitro. Therefore, FGF2 appears to function as a mitogen and self-maintenance factor for murine MSCs enriched from bone marrow by negative selection.
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PMID:Characterization of mesenchymal stem cells isolated from murine bone marrow by negative selection. 1289 21

Overexpression of KIT protein (CD117), the product of the c-kit gene, has been shown to have important prognostic and therapeutic implications for a number of malignant neoplasms. Previous studies have shown conflicting results regarding the expression of c-kit in malignant mesothelioma. To determine whether malignant mesothelioma expresses KIT, immunohistochemistry and RT-PCR were used to analyze archived tissue from 37 cases of mesothelioma. Although a subset of mesotheliomas demonstrated specific staining with the DAKO anti-KIT antibody, in each case staining was nuclear. We could not detect c-kit mRNA by a sensitive RT-PCR assay, even in cases with strong nuclear staining. Furthermore, a second anti-KIT antibody (Cell-Marque) only demonstrated staining in a single mesothelioma case and in none of the cases that demonstrated nuclear staining. We conclude that immunoreactivity for KIT in mesothelioma does not represent expression of the c-kit gene and may represent antibody cross-reaction with nuclear proteins. Our results raise doubt about previously reported expression of KIT in mesothelioma and consequently, the applicability of therapeutic agents that target the kinase activity of KIT.
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PMID:c-Kit is not expressed in malignant mesothelioma. 1526 10

We aimed to immunohistochemically examine the expression of KIT (CD 117) in human posterior uveal melanoma and to analyze KIT-positive tumors for gene mutations. Brought into a tissue microarray (TMA) format were 101 formalin-fixed, paraffin-embedded posterior uveal melanomas. Immunohistochemistry was performed using the polyclonal anti-CD117 antibody from Dako (A4502). In ten selected KIT-positive tumors, exons 2, 8, 9, 11, 13 and 17 were sequenced. Of the 101 cases, 89 (88%) could be evaluated on the TMAs. Immunohistochemistry for CD 117 was weakly positive in 5 cases (6%), moderately positive in 10 cases (12%) and strongly positive in 57 cases (69%). No KIT mutations were detected in the analyzed exons. In conclusion, human posterior uveal melanoma frequently expresses CD117 at high levels. Although KIT mutations could not be found, it appears justified to investigate the utility of imatinib mesylate in the treatment of these patients.
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PMID:Sequence analysis and high-throughput immunohistochemical profiling of KIT (CD 117) expression in uveal melanoma using tissue microarrays. 1451 77

We sought to determine the expression and prognostic significance of HER2 and c-KIT proteins in nasopharyngeal carcinoma (NPC). In this retrospective study, immunohistochemical stains for HER2 and c-KIT were performed on formalin-fixed paraffin-embedded sections from 49 patients with NPC who were treated at our hospital from 1971 to 2000. The clinical and immunohistochemical data were correlated, including gender, ethnic origin, age, histological type, EBV status (EBER in situ hybridization), stage, and overall survival. HER2 expression was not found in the tested samples. C-KIT overexpression was found in 33% (16/49) of the patients. Nine of the 16 samples (56%) were strongly positive for c-KIT protein (staining of >50% of the tumor cells). C-KIT expression was associated with younger age. C-KIT was not found in patients with squamous carcinoma or in those with negative EBV status, although these two groups consisted of only five patients each. Although c-KIT-positive cases tended to be associated with slightly better survival, this was not statistically significant. C-KIT protein was expressed in one third of the NPC patients in this study, only in EBV-positive, undifferentiated, or nonkeratinizing carcinoma patients. Further study is needed to check whether c-KIT expression is correlated with c-KIT DNA mutations and to test the possibility of treatment with imatinib mesylate (Gleevec). HER2 protein was negative in the same tested specimens.
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PMID:Expression of HER2 and C-KIT in nasopharyngeal carcinoma: implications for a new therapeutic approach. 1455 87

Adenoid cystic carcinoma is an indolent salivary gland malignancy that is associated with a poor long-term prognosis. The distinction of adenoid cystic carcinoma from other head and neck neoplasms can occasionally be problematic, particularly in small biopsies. Recent studies suggest that KIT (CD117) might be useful as an ancillary marker for adenoid cystic carcinoma; however, the expression of KIT in other benign and malignant head and neck neoplasms, including those that might mimic adenoid cystic carcinoma, has not been well studied. Here we use two different antibodies against KIT to evaluate its expression in a series of 66 adenoid cystic carcinomas compared with its expression in 98 other neoplasms of the head and neck. Overall, 94% (n = 62) of adenoid cystic carcinomas from various anatomic sites and of various histologic subtypes were positive for at least one of the KIT antibodies, and 77% (n = 50) of adenoid cystic carcinoma cases were positive for both antibodies. This contrasted with only 8% (n = 8) of other head and neck neoplasms that were positive for both KIT antibodies (P <.001). It was of note that certain neoplasms, including pleomorphic adenoma, basal cell adenoma, polymorphous low-grade adenocarcinoma, and basal cell carcinoma, that can show histologic overlap with adenoid cystic carcinoma had significantly less KIT immunoreactivity than did adenoid cystic carcinoma (P <.001). In contrast, KIT expression did not reliably distinguish adenoid cystic carcinoma from basal cell adenocarcinoma and basaloid squamous carcinoma (P >.05). The overall sensitivity of the two KIT antibodies for adenoid cystic carcinoma was 82-89%, and the specificity was 87-88%. The findings in this study support the potential use of KIT immunoexpression for distinguishing adenoid cystic carcinoma from many other benign and malignant head and neck neoplasms.
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PMID:Expression of KIT (CD117) in neoplasms of the head and neck: an ancillary marker for adenoid cystic carcinoma. 1468 23

Cyclooxygenase (COX) is a key enzyme in the conversion of arachidonic acid to prostaglandins, prostacyclin, and thromboxane. COX-2 is expressed in many epithelial malignancies, particularly those of the gastrointestinal (GI) tract. COX-2 has been implicated in the pathogenesis of cancers and has a significant negative effect on survival. To date, little is known about the expression of COX-2 in nonepithelial tumors. The objective of this study was to evaluate the expression of COX-2 in GI stromal tumors (GISTs). We evaluated 15 GISTs using tissue microarray. Tissue blocks were retrieved and stained with hematoxylin and eosin to evaluate the histological tumor type. In addition, immunohistochemistry was performed for COX-2, the macrophage marker, CD68 (KP-1), and KIT (CD117). Two pathologists then evaluated the tissues to determine the extent and intensity of COX-2 expression. The location of CD68-positive cells, and whether these cells were COX-2 positive, was also evaluated. The results showed that 80% (12 of 15) of the tumors expressed COX-2. Expression was noted in the cytoplasm of the tumor cells, with variable intensity of staining among the tumors. COX-2 was expressed in both epithelial cell and spindle cell tumors, but appeared stronger in epithelial lesions. In mixed lesions, COX-2 was expressed to a greater extent in epithelial areas. There was a greater extent of COX-2 expression in malignant tumors and tumors located within the stomach. Tumor-infiltrating macrophages (CD68-positive cells) were identified in all of the lesions; in 80% of cases, those macrophages also expressed COX-2. This study is the first to demonstrate COX-2 expression in stromal lesions of the GI tract. The enzyme may play a role in the proliferation of these lesions, suggesting the potential use of nonsteroidal anti-inflammatory drugs in treatment.
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PMID:Cyclooxygenase-2 expression in stromal tumors of the gastrointestinal tract. 1469 8


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