Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amplification of the HER2 oncogene in breast cancer identifies patients who are likely to respond to anti-HER2 mAb therapy. Current clinical practice dictates that all breast cancers first undergo HER2 screening by IHC. Strongly positive (3+ on a 0-to-3+ scale) IHC cases are considered as HER2-amplified tumors and are not evaluated further because of the strong correlation between HER2 gene amplification as measured by FISH and 3+ IHC. This strong correlation has recently been questioned, and some data suggest that over 50% of 3+ IHC HER2 immunostains may not be due to HER2 gene amplification. To help resolve this discrepancy, the authors developed a quantitative PCR assay for HER2. Quantitative PCR was used to determine the amount of HER2 DNA relative to a control gene, IF2 (eukaryotic translation initiation factor, 2p11.1-q11.1). The PCR assay is performed on genomic DNA isolated from paraffin-embedded breast cancer tissue. The PCR assay developed is a monoplex assay in which the HER2 and IF2 PCRs are performed in separate cuvettes. Cases of HER2 FISH amplified breast cancer and HER2 FISH nonamplified breast cancer were chosen for study by monoplex HER2 PCR. HER2 overexpression was evaluated by IHC. Twenty-two cases of HER2-positive and 22 cases of HER2-negative breast cancer, as determined by FISH, were assayed for HER2 by PCR and IHC. Sixteen of the 44 cases were interpreted as 3+ IHC. All 16 showed HER2 amplification by PCR and 15 showed HER2 amplification by FISH. One FISH negative case was found to be HER2 amplified by PCR and showed 3+ IHC stain, suggesting the FISH result in this case was underinterpreted. Two FISH positive cases were found to be negative by PCR and negative in IHC as well, suggesting the FISH result in these cases was overinterpreted. The authors conclude that 3+ IHC membrane staining correctly identifies neoplasms showing HER2 gene amplification. Monoplex HER2 PCR may offer significant advantages over both IHC and FISH for HER2 testing in breast cancer.
Appl Immunohistochem Mol Morphol 2005 Dec
PMID:Correlation of HER2 gene amplification with immunohistochemistry in breast cancer as determined by a novel monoplex polymerase chain reaction assay. 1628 Jun 62

Extramammary Paget's disease (EMPD) is a rare condition whose importance is amplified by its association with either cutaneous or internal malignancy. Recently it has been shown that EMPD is not a single disease but can be divided into cutaneous and endodermal subtypes. The authors studied 12 new cases of immunohistochemically well-characterized EMPD, including HER-2/neu and CDX-2 immunophenotyping. The latter represents a novel application of this nuclear transcription factor, considered to be a relatively specific IHC marker for gastrointestinal-type epithelium. Cutaneous EMPD, accounting for 10 of the 12 (83%) cases, was CDX2-/HER2+; endodermal EMPD, accounting for 2 of the 12 (17%) cases, was CDX2+/HER2-. Four of the 12 cases (33%) were associated with a malignancy (two cutaneous adenocarcinomas, two colorectal carcinomas). The two cases of cutaneous adenocarcinoma occurred in the cutaneous group (2/10 [20%]), while the two cases of rectal carcinoma (one invasive, one in situ) occurred in the endodermal group (2/2 [100%]). Since EMPD subtypes have specific implications with regard to cancer risk, immunophenotyping should be performed in all cases. CDX-2 immunoreactivity may be useful in the subtyping of EMPD.
Appl Immunohistochem Mol Morphol 2005 Dec
PMID:Potential diagnostic utility of CDX-2 immunophenotyping in extramammary Paget's disease. 1628 Jun 63

Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs.
Appl Immunohistochem Mol Morphol 2005 Dec
PMID:High-resolution immunophenotyping of subcellular compartments in tissue microarrays by enzyme metallography. 1628 Jun 69

Regulation of breast cancer growth by estrogen is mediated by estrogen receptors (ER) in nuclear and extranuclear compartments. We assessed the structure and functions of extranuclear ER that initiate downstream signaling to the nucleus. ER, including full-length 66-kDa ER and a 46-kDa ER splice variant, are enriched in lipid rafts from MCF-7 cells with (MCF-7/HER-2) or without (MCF-7/PAR) HER-2 gene overexpression and co-localize with HER-1 and HER-2 growth factor receptors, as well as with lipid raft marker flotillin-2. In contrast, ER-negative MCF-7 cells do not express nuclear or lipid raft ER. ER knockdown with siRNA also elicits a marked loss of ER in MCF-7 cell rafts. In MCF-7/PAR cells, estrogen enhances ER association with membrane rafts and induces rapid phosphorylation of nuclear receptor coactivator AIB1, actions not detected in ER-negative cells. Thus, nuclear and lipid raft ER derive from the same transcript, and extranuclear ER co-localizes with HER receptors in membrane signaling domains that modulate downstream nuclear events leading to cell growth.
Mol Cell Endocrinol 2006 Feb 26
PMID:Estrogen receptors in membrane lipid rafts and signal transduction in breast cancer. 1638 89

Taking a series of repeat biopsies or fine needle aspirates of a tumor during the course of therapy can provide information about treatment-induced changes in tumor biomarkers and help monitor patient response to adjuvant therapy. It is hoped that analysis of biomarkers in serial biopsies will also further our understanding of the molecular mechanisms that determine a tumor's response or resistance to therapy, may facilitate investigation of molecular biology of tumor response, and may provide useful information informing the development of new drugs for breast cancer therapy. In this chapter, practical, clinical considerations in the taking of repeat biopsies are considered and protocols for the taking of fine needle aspirates and core-cut/trucut biopsies are detailed. Their assessment for biomarkers indicative of cellular proliferation, apoptosis, and endocrine response/resistance such as estrogen and progesterone receptor status, HER2 and epidermal growth factor receptor are considered.
Methods Mol Med 2006
PMID:Serial biopsies/fine-needle aspirates and their assessment. 1649 90

Fluorescence in situ hybridization (FISH) is increasingly recognized as the most accurate and predictive test for both HER2 gene amplification or expression and response to Herceptin therapy in breast cancer. Diagnostic procedures for FISH require rigorous quality control, as with all diagnostic procedures, which rely on standardized methodologies. We describe the use of FISH for HER2 in our own laboratory, based on more than 4000 diagnostic assays, and the optimal approaches to scoring HER2 gene amplification in breast cancer.
Methods Mol Med 2006
PMID:Detection of HER2 gene amplification by fluorescence in situ hybridization in breast cancer. 1649 9

Several studies have shown that HER-2/neu (erbB-2) blocking therapy strategies can cause tumor remission. However, the responsible molecular mechanisms are not yet known. Both ERK1/2 and Akt/PKB are critical for HER-2-mediated signal transduction. Therefore, we used a mouse tumor model that allows downregulation of HER-2 in tumor tissue by administration of anhydrotetracycline (ATc). Switching-off HER-2 caused a rapid tumor remission by more than 95% within 7 d of ATc administration compared to the volume before switching-off HER-2. Interestingly, HER-2 downregulation caused a dephosphorylation of p-ERK1/2 by more than 80% already before tumor remission occurred. Levels of total ERK protein were not influenced. In contrast, dephosphorylation of p-Akt occurred later, when the tumor was already in remission. These data suggest that in our HER-2 tumor model dephosphorylation of p-ERK1/2 may be more critical for tumor remission than dephosphorylation of p-Akt. To test this hypothesis we used a second mouse tumor model that allows ATc controlled expression of BXB-Raf1 because the latter constitutively signals to ERK1/2, but cannot activate Akt/PKB. As expected, downregulation of BXB-Raf1 in tumor tissue caused a strong dephosphorylation of p-ERK1/2, but did not decrease levels of p-Akt. Interestingly, tumor remission after switching-off BXB-Raf1 was similarly efficient as the effect of HER-2 downregulation, despite the lack of p-Akt dephosphorylation. In conclusion, two lines of evidence strongly suggest that dephosphorylation of p-ERK1/2 and not that of p-Akt is critical for the rapid tumor remission after downregulation of HER-2 or BXB-Raf1 in our tumor model: (i) dephosphorylation of p-ERK1/2 but not that of p-Akt precedes tumor remission after switching-off HER-2 and (ii) downregulation of BXB-Raf1 leads to a similarly efficient tumor remission as downregulation of HER-2, although no p-Akt dephosphorylation was observed after switching-off BXB-Raf1.
Mol Carcinog 2006 May
PMID:Dephosphorylation of p-ERK1/2 in relation to tumor remission after HER-2 and Raf1 blocking therapy in a conditional mouse tumor model. 1649 87

HER2 overexpression is one of the most recognizable molecular alterations in breast tumors known to be associated with a poor prognosis. In the study described here, we explored the effect of HER2 overexpression on the sensitivity of breast cancer cells to the growth-inhibitory effects of 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), a synthetic triterpenoid, both in vitro and in vivo in a xenograft model of breast cancer. Both cell growth and colony formation in the soft agar assay, a hallmark of the transformation phenotype, were preferentially suppressed in HER2-overexpressing cell lines at low concentrations of CDDO, whereas growth-inhibitory effects at high concentrations did not correlate with the expression level of HER2. CDDO dose-dependently inhibited phosphorylation of HER2 in HER2-overexpressing cells and diminished HER2 kinase activity in vitro. CDDO induced the transactivation of the nuclear receptor peroxisome proliferator-activated receptor-gamma in both vector control and HER2-transfected MCF7 cells. Dose-response studies showed that the growth inhibition seen at lower concentrations of CDDO correlated with induction of the tumor suppressor gene caveolin-1, which is known to inhibit breast cancer cell growth. CDDO also reduced cyclin D1 mRNA and protein expression. In vivo studies with liposomally encapsulated CDDO showed complete abrogation of the growth of the highly tumorigenic MCF7/HER2 cells in a xenograft model of breast cancer. These findings provide the first in vitro and in vivo evidence that CDDO effectively inhibits HER2 tyrosine kinase activity and potently suppresses the growth of HER2-overexpressing breast cancer cells and suggest that CDDO has a therapeutic potential in advanced breast cancer.
Mol Cancer Ther 2006 Feb
PMID:Synthetic triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid induces growth arrest in HER2-overexpressing breast cancer cells. 1650 5

There is an increasing clinical demand for HER2 analysis in breast cancer, especially since the release of trastuzumab. The authors assessed the ability of immunohistochemistry to detect HER2 overexpression in invasive mammary carcinomas (IMC) using five antibodies. Paraffin-embedded samples of 86 IMCs (T2N0) were used to compare the immunohistochemical overexpression of HER2 using two polyclonal antibodies (HercepTest [DAKO] and A0485 [DAKO]) and three monoclonal antibodies (CB11 from two different laboratories, Biogenex and Novocastra, and 4D5 [Genentech]). All immunostainings were scored according to the FDA-approved HercepTest recommendations. The HercepTest-positive cases were compared with gene amplification by FISH (Oncor Inform, Ventana). The HercepTest was positive in 31 of the 86 cases (36.1%). The DAKO antibody A0485 was positive in 25 of the 66 (37.8%). Monoclonal antibody 4D5 was positive in only 15 of the 86 cases (17.4%). There was almost total agreement in results between the two CB11 antibodies: 25 of the 86 positive cases (29.1%). All cases positive for CB11 or 4D5 were HercepTest positive. Most of the HercepTest 2+ cases were negative when using either monoclonal antibody. FISH was positive in 19 of the 20 HercepTest 3+ cases and negative in 5 HercepTest 2+ cases. Three CB11-2+ cases showed no amplification by FISH. In three FISH-positive cases the immunohistochemistry showed no overexpression by all antibodies used. These findings suggest that immunohistochemistry may be used reliably as a primary methodology for evaluating HER2; however, the use of polyclonal antibodies may not be adequate to assess HER2 overexpression. CB11, regardless of the manufacturer (Biogenex or Novocastra), showed better concordance with FISH (kappa=0.83) than did the polyclonal antibodies.
Appl Immunohistochem Mol Morphol 2006 Mar
PMID:Selecting antibodies to detect HER2 overexpression by immunohistochemistry in invasive mammary carcinomas. 1654 Jul 40

The cellular and molecular effects of the proteasome inhibitor bortezomib on breast cancer cells are as yet poorly characterized. Here, in a panel of six breast cancer cell lines, bortezomib reduced viability in a concentration-dependent, time-dependent, and cell line-dependent manner. Proteasome activity was relatively high in two of the three more resistant cell lines. No relationship was observed between bortezomib effects on cell viability and expression/phosphorylation of HER-2, epidermal growth factor receptor (EGFR), AKT, or extracellular signal-regulated kinase 1/2 (ERK1/2). Molecular effects of bortezomib were further studied in SK-BR-3 and BT-474 cells because they share expression of EGFR and overexpression of HER-2 while, in contrast, SK-BR-3 cells were 200-fold more sensitive to this agent. Proteasome activity was inhibited to a similar extent in the two cell lines, and known proteasome substrates accumulated similarly. In SK-BR-3 cells, a marked inhibition of EGFR, HER-2, and AKT phosphorylation was observed at a clinically relevant concentration of bortezomib. In contrast, phosphorylation of Raf/mitogen-activated protein kinase kinase 1/2 (MEK 1/2)/ERK1/2 increased by bortezomib. In BT-474 cells, the effects were much less pronounced. Treatment of SK-BR-3 cells with bortezomib combined with pharmacologic inhibitors of EGFR, phosphatidylinositol 3'-kinase, or MEK resulted in modest or no enhancement of the effects on cell viability. Collectively, these results show that bortezomib has differential cellular and molecular effects in human breast cancer cells. The bortezomib-observed effects on signaling transduction molecules might be relevant to help to design mechanistic-based combination treatments.
Mol Cancer Ther 2006 Mar
PMID:Differential cellular and molecular effects of bortezomib, a proteasome inhibitor, in human breast cancer cells. 1654 81


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>