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)

The epidermal growth factor (EGF) receptor is a transmembrane, cell-surface glycoprotein that mediates the mitogenic action of a family of ligands, including EGF and transforming growth factor alpha (TGF alpha). Perturbation of this signal transduction pathway by exposure to excess ligand, by overproduction of the normal EGF receptor, or by the presence of specific mutated forms of this receptor can result in dramatic alterations in cellular phenotype, including malignant transformation. Overstimulation of normal cells is avoided by precise control of the synthesis and degradation of EGF receptors. Regulation occurs at multiple levels, including transcriptional control. A number of DNA-binding proteins have now been identified which positively and negatively modulate EGF receptor gene transcription.
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PMID:Epidermal growth factor receptor regulation and function. 210 2

The ras gene product (p21) is a GTP-binding protein and has been thought to transduce signals regulating proliferation or differentiation of cells. Like other GTP-binding proteins, p21.GTP is an active conformation, which can transduce the signals downstream, whereas p21.GDP is an inactive one. Recently, we have shown that p21.GTP levels increased in cells treated with fetal bovine serum or platelet-derived growth factor to initiate DNA synthesis. In this paper, we report that epidermal growth factor can also increase the amounts of p21.GTP in the cells. Effects of epidermal growth factor and platelet-derived growth factor are not additive. In contrast, mutant [Val12]p21, which has transforming activity, responded neither to platelet-derived growth factor nor to epidermal growth factor. We also found that the ratio of p21.GTP to p21.GDP increased 3- to 4-fold in transformants carrying activated erbB-2/neu or v-src oncogenes. These results strongly suggest an important role of p21 in transduction of signals for both normal proliferation and malignant transformation through growth factor receptors with tyrosine kinase activity or related oncogene products.
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PMID:Accumulation of p21ras.GTP in response to stimulation with epidermal growth factor and oncogene products with tyrosine kinase activity. 214 78

The immunohistochemical and DNA profiles of two cases of florid papillomatosis of the nipple (FPN) were compared with the immunohistochemical and DNA profiles of mammary intraductal carcinomas (IC) to assess the relationship between these two proliferative neoplasms. Both examples of FPN were circumscribed papillary tumors in the subareolar breast that showed cytologic atypia, intraductal necrosis, and a distinct myoepithelial cell layer. An antibody to muscle-specific actin (MSA) decorated a continuous myoepithelial layer in one case that was confirmed by electron microscopy. MSA showed patchy, discontinuous staining of apparent myoepithelium in the ICs. Flow cytometric analysis showed that both FPN lesions were diploid, rapidly proliferating lesions with S-phase fractions of 10.9% and 34.4%. One IC was aneuploid, and the five diploid neoplasms showed S-phase fractions ranging from 6.4 to 15.8%. In FPN many epithelial cells stained intensely for S-100 protein, but each IC also showed at least focal expression of S-100 protein. One case of FPN was focally positive for gross cystic disease fluid protein 15 (GCDFP-15), but neither stained for tumor-associated glycoprotein-72 (TAG-72) nor for the product of the c-erbB-2 oncogene. In comparison, three ICs expressed focal GCDFP-15, four stained for TAG-72, and one was positive for the c-erbB-2 oncogene product. These preliminary observations suggest that the tandem proliferation of epithelial and myoepithelial cells and the preservation of a normal structural relationship between the two appears to separate FPN from intraductal carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Florid papillomatosis of the nipple: immunohistochemical and flow cytometric analysis of two cases. 216 32

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

Thyroid hormone (T3) and retinoic acid (RA) receptors mediate ligand-dependent inhibition of epidermal growth factor (EGF) receptor and c-erbB2/neu promoter activities. Ligand-activated T3 and RA receptors act via a 36 bp 5' fragment of the EGF receptor gene in vivo and, in the presence of nuclear extract, bind with high affinity to this region in vitro. Both ligand binding and DNA binding domains of T3 and RA receptors are required for promoter inhibition. When both receptors are expressed in the presence of a single ligand, inhibition is reversed, indicating that the hormone-activated receptor is competed by the unliganded receptor. These results suggest that ligand regulates transcriptional inhibitory functions of the T3 and RA receptors and describe novel regulation of growth factor receptor gene expression.
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PMID:Ligand-activated thyroid hormone and retinoic acid receptors inhibit growth factor receptor promoter expression. 216 50

Recently cervical cancer is defined as a sexually-transmitted disease, and human papillomavirus (HPV) has been focused as one of its etiologic agents. It is known that cervical cancer is extraordinarily rare in non-human mammals that have the estrous cycle. In contrast, cervical cancer is frequent in human beings which have lost the estrous cycle, and subsequently evolved a sexual behavior irrespective of the menstrual phase. Therefore, upon the hypothesis that the estrous cycle is a period protected from a sexually transmitted disease, we studied the status of local defence mechanism and growth/differentiation of normal cervical epithelium during the menstrual cycle and pregnancy. Then, the influence of HPV-infection on the growth and differentiation of cervical epithelium was analyzed. As a local immune system of the cervix, both IgA and IgG are secreted in the cervical mucus, and the levels in the follicular phase were significantly higher than those during the luteal phase and pregnancy. An existence of local defence mechanism in the follicular phase is suggested. Analysis of a cell proliferation antigen Ki-67 in normal cervix revealed that parabasal cells enter the cell cycle more frequently in the luteal phase than in the follicular phase. Basal and reserve cells are usually resting, but a few cells enter the cell cycle during the luteal phase and during pregnancy. Since cycling cells are more susceptible to viral infection, the basal and/or reserve cells during the luteal phase and pregnancy are suggested to be under the risk for HPV infection. As factors regulating growth and differentiation of cervical squamous epithelium, immunohistochemical expression of estrogen receptor (ER), progesterone receptor (PR), epidermal growth factor receptor (EGFR), c-erbB-2 protein, adult T-cell leukemia-derived factor (ADF), and HPV DNA was examined. In normal cervix, basal cells were usually ER-positive and PR-negative. Parabasal cells were ER-positive and PR-negative in the follicular phase, while they were ER-negative and PR-positive during the luteal phase and pregnancy. Considering the results of Ki-67 expression, the ER-negative and PR-positive status is possibly related to the proliferation of the cervical squamous epithelium. In cervical condylomas, basal cells infected by HPV6/11 were ER-positive, but HPV16/18-infected cells were ER-negative. Neoplastic cells of CINs and invasive squamous carcinomas containing HPV DNA 16/18 were ER-negative, while those containing HPV DNA 31/33/35 were weakly ER-positive. PR was positive in 2 of 2 condylomas, 18 of 26 CINs, and 13 of 22 invasive carcinomas.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Studies on pathogenesis of cervical carcinoma based on the analysis of growth and differentiation mechanism of cervical epithelium]. 217 18

Amplification is one mechanism for activation of oncogenes and results in an excess of DNA template, which can lead to overproduction of oncogene-specific RNA and protein. Amplification of oncogenes has been observed in different tumor tissues. In certain cases amplification and overexpression of particular oncogenes have been correlated with tumor progression and clinical behavior. The best example is neuroblastoma in which the N-myc oncogene frequently is found to be amplified. Over 1,000 patients with breast cancer have been studied for amplification of the c-erbB-2 oncogene until now. The evidence from the studies that amplification of c-erbB-2 is correlated with poor prognosis is in our opinion not convincing. More and more investigations about oncogenes and disease prognosis will take place rather at the protein level than at the DNA level.
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PMID:Amplification of oncogenes and disease prognosis. 218 30

Breast cancer is a leading cause of cancer death among women. Factors useful for determining the prognosis of breast cancer include axillary lymph node involvement, tumor size, hormonal receptor status, nuclear grade, and relative DNA content. The c-erbB-2 protooncogene is amplified in 10-40% of primary breast tumors, as well as in breast cancer cell lines; where it is amplified there is increased expression of its product. We have investigated the DNA content and c-erbB-1 protein expression in tumor cell lines and in breast cancer patient specimens by multiparameter flow cytometry. The study was enabled by the discovery that both cellular integrity and c-erbB-2 antigen reactivity were preserved in cells and tissues following fixation in 70% ethanol. We demonstrate that flow cytometric analysis of c-erbB-2 expression in populations of ethanol-fixed tumor cells is a reliable and sensitive quantitative method that correlates well with previously documented semiquantitative techniques. This is a feasible method for analyzing archived clinical samples, and further allows correlations between c-erbB-2 levels and other cellular parameters. Additionally, this method detects abnormal populations not identified by DNA content analysis alone. Further studies utilizing this approach are necessary to evaluate the prognostic value of this oncoprotein in human breast cancer.
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PMID:Analysis of c-erbB-2 protein expression in conjunction with DNA content using multiparameter flow cytometry. 218 18

The localization of DNA replicating cells, epidermal growth factor (EGF) receptor-expressing cells and ras oncogene product p21 (p-21ras) positive cells were examined in various skin tumours to elucidate the role of EGF receptor and p21ras in the epidermis. Normal skin, keratoacanthoma (KA), solar keratosis (SK), Bowen's disease (BD), squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and extramammary Paget's disease (PD) were studied. EGF receptors were seen in proliferating layers, where DNA replicating cells localize, but p21ras was found in the more differentiated layers. We conclude that EGF receptor expression is closely associated with cellular proliferation, but p21ras may play a role in the differentiation of cells in various skin tumours.
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PMID:Association of EGF receptor expression with proliferating cells and of ras p21 expression with differentiating cells in various skin tumours. 220 27

The neu gene in rat neuro/glioblastoma was found to be activated by a single point mutation in the DNA sequence encoding the transmembrane region of the neu-encoded p185 protein. The human homologue of the rat neu gene, termed c-erbB-2 or HER-2, can also be activated in vitro by a similar mutation in the corresponding region. Although the human neu gene was shown to be amplified/overexpressed in a large portion of human breast and ovarian cancer, no reports indicate that the human neu gene is activated by a point mutation in human tumor. To study the possible point mutation of neu gene in human tumors, we characterized the genomic structure in the transmembrane region of human neu gene, which in turn allowed us to determine DNA sequence in this region directly following DNA amplification by polymerase chain reaction. We analyzed 7 tumor cell lines (2 breast cancer, 1 neuroblastoma, 1 rhabdomyosarcoma, and 3 glioma) and 11 tumor tissue samples (8 breast and 3 ovarian cancers). No mutation was found in the transmembrane region of human neu gene. Our results suggest that unlike the rat neuro/glioblastoma, the single point mutation in the transmembrane region of the human neu gene is a rare event in human tumors. In this study, we developed a technique for direct DNA sequencing of the transmembrane region of the human neu gene. This technique makes it possible to screen a large number of tumor samples.
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PMID:Direct sequencing analysis of transmembrane region of human Neu gene by polymerase chain reaction. 220 83


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