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)

HER2 is an erbB/HER type 1 tyrosine kinase receptor that is frequently over-expressed in malignant epithelial tumours. Herceptin, a humanised mouse monoclonal antibody to HER2, is proven therapeutically in the management of metastatic breast cancer, significantly prolonging survival when combined with cytotoxic chemotherapeutic agents. Immunohistochemical studies suggest that non-small-cell lung cancer (NSCLC) tumours may over-express HER2. Our aim was to evaluate HER2 gene amplification and semi-quantitative immuno-expression in NSCLC. A total of 344 NSCLC cases were immunostained for HER2 expression in 2 centres using the HercepTest. Fluorescence in situ hybridisation (FISH) analysis for HER2 gene amplification was performed on most positive cases and a subset of negative cases. Fifteen cases (4.3%) demonstrated 2+ or 3+ membranous HER2 immuno-expression. There was no correlation between immuno-expression and tumour histology or grade. Tumours from higher-stage disease were more often HercepTest-positive (p < 0.001). All 4 HercepTest 3+ cases demonstrated gene amplification. One of the 5 2+ cases tested for gene amplification showed areas of borderline amplification and areas of polyploidy. None of the 19 HercepTest-negative cases demonstrated gene amplification or polyploidy (p < 0.001). Gene amplification was demonstrated in all HercepTest 3+ scoring NSCLC cases. Unlike breast cancer, gene amplification and HER2 protein over-expression assessed by the HercepTest appeared to be uncommon in NSCLC. Herceptin may therefore target only a small proportion of NSCLC tumours and be of limited clinical value in this disease, particularly in the adjuvant setting.
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PMID:Herceptest: HER2 expression and gene amplification in non-small cell lung cancer. 1130 80

The HER2/neu oncogene is overexpressed in human pancreatic cancer, but the clinical significance of that overexpression is uncertain. In the present study we investigated the antitumor efficacy of Herceptin, a new recombinant humanized anti-HER2/neu antibody, which exhibits cytostatic activity on breast and prostate cancer cells that overexpress the HER2 oncogene. That antibody may retard tumor growth in certain patients with those diseases. We quantified HER2 expression in various human pancreatic cancer cell lines and studied the bioactivity of this antibody both in vitro and in vivo. Growth inhibition by Herceptin was observed in vitro in cell lines with high levels of HER2/neu expression. Cell lines with low levels of this protein did not respond significantly to the antibody. In vivo we studied two different pancreatic cancer cell lines in an orthotopic mouse model of the disease. Herceptin treatment suppressed tumor growth in the MIA PaCa-2 tumor cell line, which expressed high levels of HER2/neu. These data suggest that Herceptin treatment of patients with pancreatic cancer who express high levels of the HER2/neu oncogene may be reasonable.
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PMID:Therapy for pancreatic cancer with a recombinant humanized anti-HER2 antibody (herceptin). 1133 75

This report summarises the clinical efficacy and safety findings from clinical trials of the new anti-HER2 monoclonal antibody Herceptin(R) (trastuzumab). Data from pivotal trials indicate that trastuzumab is active when added to chemotherapy in patients with advanced metastatic breast cancer. In particular, the combination significantly prolonged the median time to disease progression, increased the overall response rate, increased the duration of response, and improved median survival time by approximately 25% compared with chemotherapy alone. Furthermore, trastuzumab is active as a single agent in women with HER2-positive metastatic breast cancer, inducing durable objective tumour responses. In total, 15% of patients who had received extensive prior treatment for metastatic disease had an objective response. The median duration of response was 9.1 months following administration of single-agent trastuzumab. Notably, 2% of patients were free of disease progression at 6 months. The safety profile of trastuzumab either given alone or in combination was favourable.
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PMID:Clinical trials of Herceptin(R) (trastuzumab). 1134 96

The human epidermal growth factor receptor HER2 or C-erbB-2/neu is a tyrosine kinase membrane receptor, which when activated, induces a phosphorylation cascade in cytoplasmic kinases leading to increased protein transcription and cellular growth. HER2 plays an important role in the biology of breast cancer, an observation that has led to the selection of HER2 as a potential target for breast cancer treatment. Trastuzumab (Herceptin(R)) is the first anti-HER2 monoclonal antibody that has shown a survival benefit in metastatic breast cancer patients with HER2-positive tumours (Norton et al., Proc ASCO 2000 18, 127a (abstract 483)). Tumour HER2 status should no longer be ignored because of its direct implications for the optimal management of breast cancer patients. A high priority for future research is to refine and standardise HER2 testing in order to minimise false-negative results. Furthermore, this procedure would overcome current issues relating to test reproducibility between pathology laboratories and definitions of HER2 positivity. In the meantime, a HER2-positive status on testing using any approved technique has implications for clinical practice (Fig. 1). The treatment algorithm given in Fig. 1 considers the lack of level 1, evidence-based studies that demonstrate convincingly the value of HER2 as a predictive marker for resistance or sensitivity to classic forms of breast cancer therapy (Piccart et al., Eur J Cancer 2000, 36, 1755-1761). In addition, the algorithm incorporates the available data from 1999-2000, which were generated from prospective trials exploring the value of trastuzumab both as a single agent and in combination with chemotherapy.
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PMID:Closing remarks and treatment guidelines. 1134 98

A fundamental mechanism of genetic alteration is amplification of entire gene sequences that results in overexpression of a gene product or protein. If the amplified gene is a member of the oncogene family and/or a regulator of DNA replication or cell cycle progression, overexpression of this oncoprotein may result in enhanced growth advantages for these cells. Amplification of one such oncogene, HER2 (neu, erbB-2), in up to 35% of human breast cancers is associated with a poor prognosis but may predict response to various therapeutic modalities. FDA-approved assays are available to detect the HER2 protein receptor or the HER2 gene sequence to determine eligibility for Herceptin treatment or adriamycin treatment in node positive patients, respectively. As testing for HER2 is becoming more common in the clinical laboratory, we provide an overview of the biology, diagnostic methods, and emerging clinical value of HER2 gene amplification.
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PMID:HER2: the neu prognostic marker for breast cancer. 1134 19

HER2 is a ligand-less tyrosine kinase receptor of the ErbB family that is frequently overexpressed in breast cancer. It undergoes proteolytic cleavage that results in the release of the extracellular domain and the production of a truncated membrane-bound fragment, p95. We show that HER2 shedding is activated by 4-aminophenylmercuric acetate (APMA), a well-known matrix metalloprotease activator, in HER2-overexpressing breast cancer cells. The HER2 p95 fragment, which appears after APMA-induced cleavage, is phosphorylated. We analyzed 24 human breast cancer specimens, and a phosphorylated M(r) 95,000 HER2 band could be detected in some of them, which indicated that the truncated receptor is also present in vivo. The activation of HER2 shedding by APMA in cells was blocked with batimastat, a broad-spectrum metalloprotease inhibitor. Trastuzumab (Herceptin; Genentech, San Francisco, CA), a humanized monoclonal antibody directed at the HER2 ectodomain, which has been shown to be active in patients with HER2-overexpressing breast cancer, inhibited basal and induced HER2 cleavage and, as a consequence, the generation of phosphorylated p95. This inhibitory effect of trastuzumab was not shared by 2C4, an antibody against a different epitope of the HER2 ectodomain. The inhibition of basal and APMA-induced cleavage of HER2 by trastuzumab preceded antibody-induced receptor down-modulation, which indicated that the effect of trastuzumab on cleavage was not attributable to a decrease in cell-surface HER2 induced by trastuzumab. We propose that the inhibition of HER2 cleavage and prevention of the production of an active truncated HER2 fragment represent a novel mechanism of action of trastuzumab.
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PMID:Trastuzumab (herceptin), a humanized anti-Her2 receptor monoclonal antibody, inhibits basal and activated Her2 ectodomain cleavage in breast cancer cells. 1140 46

HER2 overexpression occurs in 25% of breast cancers and seems to correlate with poor prognosis. HER2 overexpression may predict tamoxifen failure and different response rates to chemotherapeutic agents such as the taxanes and anthracyclines. The detection of HER2 and its overexpression is performed using fluorescent in situ hybridisation (FISH) and/or immunohistochemistry (IHC). Trastuzumab [Herceptin (H)] is a humanised IgG monoclonal antibody specific for the growth factor receptor HER2. Pre-clinical trials using monoclonal antibodies have shown inhibition of breast tumour growth in athymic nude mice. Phase II and III clinical trials have evaluated the efficacy and safety of Herceptin in women with metastatic breast cancer in combination with other agents and as a single agent. Currently, Trastuzumab and paclitaxel is the only combination indicated for the treatment of patients with metastatic breast cancer whose tumours overexpress HER2. It is also indicated as a single agent in women with HER2-overexpressing metastatic breast cancer that has progressed after previous chemotherapy. Herceptin is a well-tolerated drug and the side-effects that are commonly seen with chemotherapy, such as neutropenia, alopecia and mucositis, are rarely observed. The main risk factors for cardiotoxicity are concurrent or previous anthracycline exposure. The potential role of Herceptin in the adjuvant setting is currently being evaluated.
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PMID:From HER2 to herceptin. 1146 47

The study was performed for answering the question whether metastatic breast cancer has the same overexpression of HER2/neu as primary breast tumor. We assumed that study on this subject could give a valuable information for proper interpretation of HER2/neu overexpression in breast cancer patients designated for therapy with Herceptin. Our study was performed on 71 breast cancer patients qualified for clinical trial with Herceptin therapy. All patients selected for this trial have had surgery and two episodes of unsuccessful adjuvant therapy. Tissue samples were routinely fixed in 4% formalin and embedded in paraffin. Immunohistochemical assays were performed on 5 microns slides using DAKO HercepTest and semi-quantitative methods to determine HER2 protein overexpression were used. All study cases were subdivided into two groups. First group--49 cases in which expression of HER2 was examined in tissue from primary breast tumors, and second group--22 cases in which expression of HER2 was examined in tissue from metastatic lesions. In the whole study group (71 cases) overexpression was confirmed in 29 (40.8%) cases. In the group of primary breast tumors overexpression of HER2 was present in 20 (40.8%) of cases. In the group of metastatic breast tumors overexpression of HER2 was present in 9 (40.9%) of cases. The result suggests that overexpression which appears in primary breast carcinoma is also preserved in metastases. Direct prove of such a conclusion, would be a study on HER2/neu expression estimated in primary and metastases in the same patients. It requires a proper quantity and quality of material. Our results indicate that there is no difference between the estimation of HER2/neu overexpression in primary and metastatic breast cancer in patients with disseminated disease after double failure of chemotherapy. Evaluation of overexpression of HER2/neu in cases of planned Herceptin therapy can be done both in material from primary and from metastatic tumor.
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PMID:Expression of HER2/neu in primary and metastatic breast cancer. 1150 77

HER2 (neu, erbB-2), a receptor related to the human epidermal growth factor receptor, has now become more important as a predictive marker of treatment response. While the value and direction of the treatment/HER2 interaction may vary, depending on the agents, dose, or schedule of drug administration, there is little disagreement that HER2 testing is an important part of breast cancer evaluation. In 1998, trastuzumab (Herceptin) was approved for the treatment of HER2-positive metastatic breast cancer patients by the Food and Drug Administration of the USA. Patients with abnormal HER2 in their breast cancer cells (generally 2 or 3+ with the HercepTest, overexpression by other immunohistochemical assays or amplification by fluorescence in situ hybridization [FISH] assay) have demonstrated the greatest response to trastuzumab treatment. It is unclear which test (method, reagent, cut-off points, etc.) is best to use to evaluate HER2 for this purpose because parallel testing of the same cancers from patients who received trastuzumab has only recently been initiated and the data are limited. It is widely believed that breast cancers without HER2 alterations will not be responsive to trastuzumab, although a clinical trial to test this specific hypothesis has not been initiated. There are also concerns that clonal heterogeneity for HER2 within a tumor, or between primary and metastatic cancer foci, may affect treatment response; yet we do not currently evaluate these parameters. Consensus regarding the best methods, reagents, or cut-off points to define HER2 status for determining trastuzumab responsivity has not yet been reached. HER2 testing for other prognostic or predictive purposes, e.g. to determine whether patients are likely to respond to other agents, such as dose-intensive doxorubicin, may be less. Data from the Cancer and Leukemia Group B trial 8541 (companion 8869) suggest that, with proper controls in high-volume laboratories, many of the available methods produce comparable results.
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PMID:HER2--a discussion of testing approaches in the USA. 1152 14

The molecular mechanisms mediating the anti-proliferative effects of the murine anti-HER2 monoclonal antibody (4D5) were investigated in HER2-overexpressing human carcinoma cell lines. Treatment with 4D5 resulted in a dramatic accumulation of BT-474 breast carcinoma cells in G1; concomitant with reduced expression of proteins involved in sequestration of the cyclin E/Cdk2 inhibitor protein p27, increased association of p27 with Cdk2 complexes and Cdk2 inactivation. No equivalent effects were observed in BT-474 cells treated with a control, non-inhibitory HER2 monoclonal antibody (FRP5) or in a HER2-overexpressing cell line insensitive to 4D5 treatment (MKN7 gastric carcinoma cells), confirming the relationship between these molecular changes and 4D5-mediated inhibition of proliferation. Increased p27 expression was also observed in 4D5-treated BT-474 cells; however an antisense approach demonstrated that this increase was not required for Cdk2 inactivation or establishment of the G1 block. These data suggest that 4D5 interferes with HER2 receptor signaling, resulting in downregulation of proteins involved in p27 sequestration. This causes release of p27, allowing binding and inhibition of cyclin E/Cdk2 complexes and inhibition of G1/S progression. This model was confirmed using a second 4D5-sensitive. HER2-overexpressing breast tumor line (SKBR3), and suggests that the dependency of a given tumor cell on elevated HER2-receptor signaling for the maintenance of p27 sequestration proteins may determine the clinical response to treatment with the humanized anti-HER2 monoclonal antibody Herceptin (trastuzumab).
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PMID:Modulation of p27/Cdk2 complex formation through 4D5-mediated inhibition of HER2 receptor signaling. 1152 16


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