Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two transplantable cell lines of human glioblastoma multiforme GL-3 and GL-5 carried an amplification and overexpression of structurally altered epidermal growth factor (EGF) receptor gene: the 140 kilodalton EGF receptors in these cases exhibited a constitutively expressed tyrosine kinase activity without the ligand. Here, we isolated the abnormal EGF receptor cDNA from GL-5 cell line, and demonstrated that this cDNA bears a single large intramolecular deletion mutation 801 base pairs long within the ligand binding domain of EGF receptor. In other regions no amino acid substitution was observed. At the level of genomic DNA, this deletion appeared to start from the 1st intron and terminate in the 6th intron of the EGF receptor gene. However, in the two lines of glioblastoma, GL-3 and GL-5, the positions of the start or the end of the deletion mutation in these introns were not identical, suggesting an involvement of a unique recombination mechanism in the formation of deletion mutation. A weak but ligand-independent transforming activity was observed in the deletion-carrying EGF receptor cDNA.
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PMID:A deletion mutation within the ligand binding domain is responsible for activation of epidermal growth factor receptor gene in human brain tumors. 216 66

Retroviral onc genes are derived from cellular proto-oncogenes that may function in normal cellular growth control. The epidermal growth factor (EGF) receptor is the proto-oncogene of erbB; both possess intrinsic protein tyrosine kinase activity, a property shared by several retroviral onc genes. The EGF receptor is a transmembrane glycoprotein with an external EGF binding domain and a cytoplasmic region that is homologous with other tyrosine kinases. erbB lacks the EGF binding and carboxyl terminal regions, which are thought to be important in regulation. The EGF receptor is regulated by several mechanisms: stimulation by ligand binding and self-phosphorylation, inhibition by heterologous phosphorylation and downregulation by ligand. EGF binding stimulates several early events, including phosphatidylinositol (PI) turnover in A431 cells. A PI kinase activity copurifies with the EGF receptor and some other tyrosine kinases, but this is a contaminant as it can be separated from the EGF receptor. Although the role of proto-onc genes in human malignancy is incompletely defined, increased numbers of EGF receptors are present in several types of human tumours. Overexpression of EGF receptors, as occurs in human epidermoid carcinoma A431 cells, can augment cell growth because of increased formation of active ligand:receptor complexes. Gene amplification is the mechanism underlying overexpression of EGF receptors in A431 cells and in some glioblastoma multiforme tumours.
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PMID:The EGF receptor: structure, regulation and potential role in malignancy. 282 44

By using Southern blot analysis, we found that in two cases of human glioblastoma multiforme, cells carried amplified c-erbB genes which bore short deletion mutations within the ligand-binding domain of the epidermal growth factor (EGF) receptor. The products of these mutated c-erbB genes were about 30 kilodalton (kDa) smaller than the normal 170-kDa EGF receptor, and the tumor cell membrane fractions containing the 140-kDa abnormal EGF receptor showed a significant elevation of tyrosine kinase activity without its ligand. In view of the similarity to the activated viral and cellular erbB genes in the avian system, these mutated and overexpressed EGF receptors might play a role in the onset or development of human glioblastoma cells.
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PMID:Amplification of the structurally and functionally altered epidermal growth factor receptor gene (c-erbB) in human brain tumors. 338 99

The objective of the present study was to determine the frequency of amplifications of three different members of the erbB gene family in human glioblastoma multiforme (GBM). We investigated 47 glial tumors (37 GBM WHO grade IV, 5 anaplastic astrocytomas WHO III and 5 astrocytomas WHO II) by Southern and Western analysis, and immunocytochemistry. Gene amplification of erbB genes in human malignant gliomas was restricted to the EGF receptor (EGFR) gene, erbB-1. We found amplification of the EGFR gene in 49% (18/37) of GBM but not in the astrocytomas WHO II/III. The erbB-2 and erbB-3 genes showed no amplification in the tumor specimens investigated in this study. At the protein level we found overexpression of the EGF receptor in 86% (32/37) by Western analysis and in 92% (34/37) by immunocytochemistry. Expression of the ERBB2 protein was present in 54% (20/37) but immunoreactivity was much weaker than for EGF receptor and in most cases barely detectable by Western analysis and immunocytochemistry. The ERBB3 protein was not expressed in the glial tumors investigated in this study. Of the three erbB genes only gene amplification and overexpression of the EGF receptor seems to have an impact on tumor progression of human gliomas. Our data from immunohistochemistry indicate that ERBB2 expression in GBM is closely correlated with EGF receptor levels and is therefore not useful as an independent prognostic parameter.
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PMID:Amplification and differential expression of members of the erbB-gene family in human glioblastoma. 776 96

Her-2/neu or c-erbB-2, a 185-kD protein is an important prognostic indicator/target for therapy in metastatic breast carcinoma. Recent reports have also identified a role for Her-2/neu overexpression in other solid tumors. We performed a retrospective analysis to evaluate the prevalence and prognostic role of Her-2/neu overexpression in patients with glioblastoma multiforme (GBM). Data collection (chart review) included demographic information, symptoms at presentation, histologic grade, survival time, and treatment offered. Testing for Her-2/neu overexpression was performed on paraffin-embedded archival tumor tissue using immunohistochemistry (IHC) (Hercep test). An IHC score of 2+ or greater was considered overexpression. An experienced pathologist who was blinded from the clinical history performed all the IHC testing. Between 1990 and 2001, 149 subjects (68 females, 81 males) with a biopsy-proven diagnosis of GBM were identified. Age range was 26 to 79 years (mean: 64 years) and overall mean survival was 12 months. Her-2/neu overexpression was detected in 23 patients (15.4%). Interestingly, the median survival for patients whose pathologic specimens revealed Her-2/neu overexpression was 4 months compared to those who lacked overexpression, in whom survival was 8 months. After adjusting for age, performance status, smoking history, and treatment, logistic regression analysis (with a survival of <3 months as the dependent variable) revealed that Her-2/neu overexpression significantly (p < 0.01) increased the odds of early mortality (<3 months). The results of our large study indicate that Her-2/neu overexpression may be a poor prognostic marker in patients with GBM. In addition, in a proportion of subjects (15.4%), Her-2/neu may be a potential target for tumor-specific monoclonal antibody therapy. The role of trastuzumab (alone or in combination with conventional therapy) needs to be evaluated.
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PMID:Role of Her-2/neu overexpression and clinical determinants of early mortality in glioblastoma multiforme. 1290 79

Epidermal growth factor variant III (EGFRvIII) is the most common alteration of the epidermal growth factor (EGF) receptor found in human tumors. It is commonly expressed in glioblastoma multiforme (GBM), where it was initially identified. This constitutively active mutant receptor leads to unregulated growth, survival, invasion, and angiogenesis in cells that express it. EGFRvIII results from an in-frame deletion of exons 2 to 7 resulting in the fusion of exon 1 to exon 8 of the EGF receptor gene creating a novel glycine at the junction in the extracellular amino terminal domain. The juxtaposition of ordinarily distant amino acids in combination with the glycine that forms at the junction leads to a novel tumor-specific epitope that would make an ideal tumor-specific target. A peptide derived from the EGFRvIII junction can be used as a vaccine to prevent or induce the regression of tumors. This peptide vaccine has now proceeded to phase 1 and 2 clinical trials where it has been highly successful and is now undergoing investigation in a larger human clinical trial for patients who have newly diagnosed GBM. In this article, the authors discuss the preclinical data that led to the human trials and the exciting preliminary data from the clinical trials.
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PMID:The epidermal growth factor variant III peptide vaccine for treatment of malignant gliomas. 1994 69

The epidermal growth factor (EGF) receptor is a receptor tyrosine kinase involved in the control of cell proliferation, and its overexpression is strongly associated with a variety of aggressive cancers. For example, 70-80% of metaplastic (cancer cells of mixed type) breast carcinomas overexpress EGF receptors. In addition, the EGF receptor is a highly significant contributor to common brain tumors (glioblastoma multiforme), both in initiation and progression (Huang P.H., Xu A.M., White F.M. (2009) Oncogenic EGFR signaling networks in glioma. Sci Signal;2:re6.). Brain metastases, an unmet medical need, are also common in metastatic cancer associated with overexpression of EGF receptors. Formation of EGF receptor homodimers is essential for kinase activation and was the basis for exploring direct inhibition of EGF receptor activation by blocking dimerization with small molecules. While inhibitors of protein/protein interactions are often considered difficult therapeutic targets, NSC56452, initially identified by virtual screening, was shown experimentally to inhibit EGF receptor kinase activation in a dose-dependent manner. This compound blocked EGF-stimulated dimer formation as measured by chemical cross-linking and luciferase fragment complementation. The compound was further shown to inhibit the growth of HeLa cells. This first-generation lead compound represents the first drug-like, small-molecule inhibitor of EGF receptor activation that is not directed against the intracellular kinase domain.
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PMID:Targeting the dimerization of epidermal growth factor receptors with small-molecule inhibitors. 2045 71