UNIPROT:P04626 - FACTA Search

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Query: UNIPROT:P04626 (erbB-2)
5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In solid tumors the predominant genetic mechanism for oncogene activation is through amplification of genes. The HER-2 (also known as ErbB2/c-erbB2/HER-2/neu) oncogene is the most frequently amplified oncogene in breast cancer and is also commonly amplified in other forms of cancer. Alongside its important role in tumor induction, growth and progression, HER-2 is also a target for a new form of chemotherapy. Since 1998, breast cancer patients have been treated with considerable success with Herceptin (trastuzumab), a recombinant antibody designed to block signaling through the HER-2 receptor. In addition to Herceptin, a large number of various HER-2 directed immunological and genetic approaches, either targeting the HER-2 receptor, its signaling pathways or both HER-2 and epidermal growth factor receptor (EGFR) together, have demonstrated promising pre-clinical potential towards HER-2 amplified carcinomas. Moreover, the HER-2 amplicon contains other genes with altered copy numbers that could be used as targets for chemotherapy. The topoisomerase IIalpha (topoIIalpha) gene (TOP2A) is located adjacent to the HER-2 oncogene at the chromosome location 17q12-q21 and is either amplified or deleted, with equal frequency, in almost 90% of HER-2 amplified primary breast tumors. Recent data suggest that amplification or deletion of TOP2A may account for both sensitivity or resistance to topoII-inhibitor-chemotherapy, depending on the specific genetic defect at the TOP2A locus. The understanding of HER-2 amplification and its role in the pathogenesis of cancer is expanding. The number of therapeutic strategies targeting HER-2 signaling pathways will most probably be introduced in the treatment of HER-2 amplified tumors within the next few years. Combining HER-2 targeting therapies with conventional forms of cytotoxic chemotherapy, where additional diagnostics tests such as those ascertaining topoIIalpha status, may be helpful for the ideal selection of patients for the combination therapy of a HER-2 targeting drug together with a cytotoxic drug. The clinical and therapeutic importance of the HER-2 and TOPO2A status of tumor cells in cancer management will only increase within the next few years.
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PMID:HER-2/neu and topoisomerase IIalpha--simultaneous drug targets in cancer. 1287 Oct 52

HER-2/neu is overexpressed in several cancers including 30% of breast carcinomas, and correlates with a poor outcome. HER-2/neu-transgenic (neu-N) mice that overexpress the non-transforming rat neu develop spontaneous mammary carcinomas and demonstrate immunotolerance to the neu protein similar to that observed in patients with neu-expressing cancers. In neu-N mice, neu-targeted vaccination induces weak T cell and negligible Ab responses sufficient to delay but not eradicate transplanted neu-expressing tumor. Here we demonstrate that passive infusion of neu-specific mAbs in sequence with whole cell vaccination significantly improves tumor-free survival over either modality alone. Importantly, treatment of neu-N mice with vaccine in combination with two distinct neu-specific Abs is particularly efficacious, preventing tumor in 70% and eradicating established tumor in 30% of neu-N mice. In vivo lymphocyte subpopulation depletion experiments demonstrate that the efficacy of Ab, alone or combined with vaccine, is dependent on both CD4(+) and CD8(+) T cells. Furthermore, the in vivo antitumor effects of vaccine and Ab are associated with a significant increase in the number and function of neu-specific CD8(+) T cells. Collectively, these observations suggest that similarly increased efficacy could be obtained by combining neu-targeted vaccination and neu-specific Abs such as trastuzumab (Herceptin) in patients with neu-expressing cancers.
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PMID:HER-2/neu-specific monoclonal antibodies collaborate with HER-2/neu-targeted granulocyte macrophage colony-stimulating factor secreting whole cell vaccination to augment CD8+ T cell effector function and tumor-free survival in Her-2/neu-transgenic mice. 1290 23

HER-2/neu protein expression and gene amplification were analyzed in a series of 85 consecutive breast carcinoma patients entered into an adriamicin/taxol primary chemotherapy trial followed by surgery, 45 of whom underwent pre-treatment fine needle aspirate (FNA). Dual color FISH (fluorescent in situ hybridization) assay revealed high-level HER-2/neu gene amplification in the immunocytochemistry (ICC) indicated 3+ cases and no, low or moderate amplification in the ICC 2+ group, consistent with previous findings in untreated patients series. Results obtained with the ICC assay CB 11 showed higher overall concordance with FISH than did the Herceptest ICC assay, but CB 11 was less accurate than Herceptest in terms of selecting patients suitable for Herceptin treatment, which is currently restricted to ICC 3+/FISH amplified patients. The only ICC 3+ low-level amplified case (non-amplified according the two more stringent criteria applied) was found with the CB 11 assay. Comparison between pre-treatment smears and post-treatment sections by FISH revealed no significant changes in the HER-2/neu gene profile. In the clinical setting these findings point to the usefulness of HER-2/neu assessment in chemotherapy-treated patients, when pre-treatment material is unavailable.
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PMID:HER-2/neu assessment in primary chemotherapy treated breast carcinoma: no evidence of gene profile changing. 1290 24

C-erbB-2 (HER2/neu) protein overexpression or amplification has been noted in some solid tumors a molecular target for tumor suppression. C-erbB-2 protein is localized on the membrane surface and is classified in the EGFR family. Trastuzumab is a humanized monoclonal antibody which binds to the extracellular domain of the c-erbB-2 protein in breast cancer cells. Good responders to trastuzumab may be ICH 2 + and FISH positive breast tumors, and ICH 3 + cancer. The response rate is approximately 15% with single administration of trastuzumab. Combination therapy with paclitaxel for the treatment of patients with metastatic cancer may bring more than 60% response and improve time to disease progression. Congestive heart failure associated with trastuzumab may be severe, and combination therapy which includes anthracyclines increases the incidence and severity of cardiac dysfunction. Other toxicities include infusion reaction.
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PMID:[Clinical implications of trastuzumab]. 1293 63

The option to treat patients suffering from ERBB-2 protein-positive invasive duct carcinomas of the breast (IDC) with Herceptin requires a precise determination of the ERBB2 status. The aim of the study was to evaluate the ERBB2 mRNA level, placing emphasis on cases with discordant findings between ERBB-2 protein expression (IHC) and a copy number of the ERBB2 gene (FISH). Thirty-nine IDCs (21 cases IHC and FISH concordant, 15 cases moderately discordant, 3 cases markedly discordant) were investigated. ERBB2 mRNA expression was determined using quantitative real-time RT-PCR (Q-RT-PCR). IDCs with negative ERBB-2 protein and without ERBB2 gene amplification had a low ERBB2 mRNA level. Cases with 3+ overexpression of the protein and with strong gene amplification (> 10 copies/tumor cell) had a significantly increased expression of ERBB2 mRNA. In 13 of 15 IDCs with moderate discrepancies (up to 10 copies of the gene per one tumor cell/negative ERBB-2 protein; without amplification/2+ protein) mRNA was low, comparable to that in cases with negative ERBB-2 protein and without ERBB2 gene amplification. In three cases with markedly discordant findings (the gene amplified/protein negative--one case; protein 3+/no amplification--2 cases), Q-RT-PCR results were within a "normal" limit. Ineffective gene amplification and protein accumulation are suggested explanations. Q-RT-PCR revealed two cases with highly expressed ERBB2 mRNA and discordant FISH and/or IHC findings. Increased effectiveness of transcription (protein 2+/high mRNA/without the gene amplification), and combined dysregulation (protein negative/high mRNA/no amplification) are possible causes of these findings. Q-RT-PCR appears useful in clarifying borderline or discrepant IHC and FISH findings.
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PMID:Relative quantification of ERBB2 mRNA in invasive duct carcinoma of the breast: correlation with ERBB-2 protein expression and ERBB2 gene copy number. 1452 Dec 61

Breast cancer patients with HER-2/neu oncogene amplification by fluorescence in situ hybridization (FISH) have been shown to have a better response to trastuzumab (Herceptin) therapy than those showing HER-2/neu protein overexpression only. Many centers currently perform FISH only on tumors showing 2+ HER-2/neu positivity by immunohistochemistry (IHC), with the assumption that 3+ positivity virtually equates with amplification. Results of FISH performed on 102 breast cancer cases over a 12-month period were correlated with HER-2/neu IHC results. FISH was performed using a ratio of HER-2/neu and chromosome 17 centromere signal counts (PathVysion; Vysis, Downers Grove, IL). Immunohistochemical expression of HER-2/neu was evaluated according to the published scoring guidelines of the HercepTest (Dako, Carpinteria, CA). Only 22 of 45 tumors with 3+ positivity (49%) showed amplification by FISH. Only 2 of 25 cases with 2+ staining by IHC (6%) showed gene amplification, and 1 of 25 cases with negative IHC staining (4%) showed weak amplification. Of the 25 cases showing oncogene amplification, 22 (88%) showed 3+ IHC positivity, 2 (8%) showed 2+ positivity, and 1 (4%) was negative by IHC. More than 50% of breast tumors showing strong 3+ HER-2/neu staining do not show oncogene amplification by FISH. Most tumors with 2+ and negative IHC also fail to amplify. In our experience, FISH studies should be performed on all 3+ and 2+ staining tumors to avoid inappropriate and toxic treatment. The decision to perform FISH on IHC-negative tumors should be guided by additional parameters, including tumor grade and estrogen receptor status.
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PMID:Strong HER-2/neu protein overexpression by immunohistochemistry often does not predict oncogene amplification by fluorescence in situ hybridization. 1525 59

HER2, a member of the human epidermal growth factor (EGF) receptor family, not only plays important roles in the progression of breast cancer tumorigenesis and metastasis, but may protect cancer cells from conventional cytotoxic therapies as well. In the current study, we evaluated the effect of targeting HER2 on radiosensitization of human breast cancer cells. Using six breast cancer cell lines with various levels of HER2 (BT474, SKBR3, MDA453, MCF7, ZR75B, and MDA468), we found that trastuzumab (Herceptin), a humanized monoclonal antibody that may inhibit breast cancer cell proliferation but does not induce apoptosis when used alone, enhanced radiation-induced apoptosis of the cells in a HER2 level-dependent manner. We furthered this study in MCF7 cells transfected for high levels of HER2 (MCF7HER2). Compared with parental or control vector-transfected MCF7 cells, MCF7HER2 cells showed increased phosphorylation of at least two important HER2 downstream molecules, protein kinase B/Akt and mitogen-activated protein kinase (MAPK), and increased resistance to radiotherapy, as shown by reduced induction of apoptosis and increased cell clonogenic survival after radiation. Exposure of the cells to trastuzumab down-regulated the levels of HER2 and reduced phosphorylation levels of Akt and MAPK in MCF7HER2 cells, and sensitized these cells to radiotherapy. When specific inhibitors of the phosphatidylinositol 3-kinase (PI3-K) and MAPK kinase (MEK) pathways were used, we found that exposure of MCF7HER2 cells to the PI3-K inhibitor LY294002 inhibited Akt phosphorylation and radiosensitized the cells, whereas the radiosensitization effect by the MEK inhibitor PD98059 was relatively weaker, albeit the phosphorylation of MAPK was reduced by PD98059 treatment. Our results indicate that the PI3-K pathway might be the major pathway for trastuzumab-mediated radiosensitization of breast cancer cells.
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PMID:Sensitization of breast cancer cells to radiation by trastuzumab. 1461 84

HER-2/neu (also known as HER2 or c-erb-B2) is a 185-kDa protein receptor with tyrosine kinase activity and extensive homology to the epidermal growth factor (EGF) receptor. HER-2/neu is expressed in many epithelial tumors and known to be overexpressed in approximately 20-25% of all ovarian and breast cancers, 35-45% of all pancreatic adenocarcinomas, and up to 90% of colorectal carcinomas. HER-2/neu overexpression represents a marker of poor prognosis. HER-2/neu-positive tumor cells are potentially good targets for tumor-reactive cytotoxic T lymphocytes which have been utilized in immunotherapeutic trials. In addition, the "humanized" monoclonal antibody Herceptin has been tested in several clinical trials and proved to be an effective adjuvant therapy for HER-2/neu-positive breast and ovarian cancers. Vaccinations aiming at generating T-cell responses are being examined in both experimental and clinical trials. Natural immunity at the level of T and B cells has been observed in patients with HER-2/neu-positive tumors confirming the immunogenicity of HER-2/neu and encouraging vaccination trials with HER-2 protein-derived subunits or synthetic peptides. This review summarizes recent data from patients with various types of HER-2/neu-overexpressing cancers carrying different HLA alleles and exhibiting preexistent immunity to HER-2/neu-derived synthetic peptides. It also discusses potential advantages of the various vaccination approaches to immunotherapy targeting the HER-2/neu molecule.
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PMID:Immunobiology of HER-2/neu oncoprotein and its potential application in cancer immunotherapy. 1468 81

Paget's disease of the nipple (PDN) is characterized by Paget's cells infiltrating from an underlying breast carcinoma into the epidermis of the nipple. The tumor cells were reported to overexpress ERBB-2 protein. There is no evidence, whether the overexpression is caused by amplification of the ERBB2 gene (as is the case of invasive duct carcinomas) or by other causes. Because the Paget's cells proliferate vividly we were interested also in cyclin D1 expression and in its relation to the number of CCND1 gene copies. To address these issues, we performed a study using fluorescence in situ hybridization on interphasic nuclei (I-FISH) on formalin fixed / paraffin embedded tissue sections from twelve women with PDN. We compared immunohistochemical (IHC) expression of the ERBB-2 protein and cyclin D1 with the copy number of the gene ERBB2 and CCND1, respectively (I-FISH). In all cases of our series we found overexpression of the ERBB-2 protein (3+), and in all of them there was a strong amplification of the ERBB2 gene (more than 10 signals per a nucleus, usually about 20). Keratinocytes of the epidermis had two signals of the gene. IHC and I-FISH revealed comparable findings in successive biopsies in two patients. Cyclin D1 was positive in seven cases. We found a moderate amplification of the CCND1 gene (up to 10 signals per a nucleus) in three patients only. Any correlation between the cyclin D1 overexpression anda copy number of the CCND1 gene was observed. Combined numerical changes of chromosome 17 and of chromosome 11 were found in seven women. It is concluded that in PDN, the ERBB-2 protein overexpression is caused by amplification of the ERBB2 gene. A specific immuno-therapy with trastuzumab (Herceptin) used in patients with invasive duct carcinoma may be also effective in patients with PDN.
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PMID:Paget's disease of the nipple: a copy number of the genes ERBB2 and CCND1 versus expression of the proteins ERBB-2 and cyclin D1. 1468 59

The HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor with extensive homology to the epidermal growth factor receptor. In this article, the association of HER-2/neu gene and protein abnormalities with prognosis and response to therapy with Herceptin and other therapies in breast cancer is presented. By considering a series of 80 published studies encompassing more than 25,000 patients, the relative advantages and disadvantages of Southern blotting, polymerase chain reaction amplification, and fluorescence in situ hybridization assays designed to detect HER-2/neu gene amplification are compared with HER-2/neu protein overexpression assays performed by immunohistochemical techniques applied to frozen and paraffin-embedded tissues and enzyme immunoassays performed on tumor cytosols. The significance of HER-2/neu overexpression in ductal carcinoma in situ and the HER-2/neu status in uncommon female breast conditions and male breast cancer also are considered. The role of HER-2/neu testing for the prediction of response to Herceptin therapy in breast cancer is presented as well as its potential impact on responses to standard and newer hormonal therapies, cytotoxic chemotherapy, and radiation. The review also will evaluate the status of serum-based testing for circulating HER-2/neu receptor protein and its ability to predict disease outcome and therapy response.
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PMID:Targeted therapy for cancer: the HER-2/neu and Herceptin story. 1469 77

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