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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoclonal antibodies specific for the p185HER2/neu growth factor receptor represent a significant advance in receptor-based therapy for p185HER2/neu-expressing human cancers. We have used a structure-based approach to develop a small (1.5 kDa) exocyclic anti-HER2/neu peptide mimic (AHNP) functionally similar to an anti-p185HER2/neu monoclonal antibody, 4D5 (Herceptin). The AHNP mimetic specifically binds to p185HER2/neu with high affinity (KD=300 nM). This results in inhibition of proliferation of p185HER2/neu-overexpressing tumor cells, and inhibition of colony formation in vitro and growth of p185HER2/neu-expressing tumors in athymic mice. In addition, the mimetic sensitizes the tumor cells to apoptosis when used in conjunction with ionizing radiation or chemotherapeutic agents. A comparison of the molar quantities of the Herceptin antibody and the AHNP mimetic required for inhibiting cell growth and anchorage-independent growth showed generally similar activities. The structure-based derivation of the AHNP represents a novel strategy for the design of receptor-specific tumor therapies.
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PMID:Rationally designed anti-HER2/neu peptide mimetic disables P185HER2/neu tyrosine kinases in vitro and in vivo. 1065 27

Amplification and/or overexpression of HER-2/neu has been shown to be both a prognostic and predictive marker in breast cancer. Recent studies have also confirmed the efficacy of Herceptin (trastuzumab) as adjuvant therapy for patients with overexpression of HER-2/neu. Therefore, it is critical that precise and reproducible assays be used in the clinical laboratory setting for determination of the HER-2/neu status in patients with breast cancer. The objective of this study was to determine the portability (reproducibility between different institutions) of the PathVysion HER-2 fluorescence in situ hybridization (FISH) assay used for detection of amplification of the HER-2/neu gene in formalin-fixed, paraffin-embedded tissue sections of invasive ductal carcinoma of the breast. Study specimens consisted of one breast tumor with a normal HER-2/neu copy number, two tumors with a low level, and one tumor with a high level of HER-2/neu amplification. The PathVysion HER-2 assay was shown to be highly reproducible on different assay days (n = 3) and between different institutions (n = 5) in the detection of amplification of the HER-2/neu gene in routinely processed clinical specimens of breast carcinoma. In addition, this study examined the feasibility of enumerating FISH signals in 20 nuclei in contrast to 60 nuclei per specimen. Although a modest increase in variation was observed when analyzing 20 compared to 60 nuclei, the mean ratios were similar. Therefore, analysis of as few as 20 nuclei with this FISH HER-2/neu assay may be sufficient for determining the amplification level of the HER-2/neu gene.
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PMID:Fluorescence in situ hybridization (FISH) for detection of HER-2/neu amplification in breast cancer: a multicenter portability study. 1067 82

Inhibitory receptors have been proposed to modulate the in vivo cytotoxic response against tumor targets for both spontaneous and antibody-dependent pathways. Using a variety of syngenic and xenograft models, we demonstrate here that the inhibitory FcgammaRIIB molecule is a potent regulator of antibody-dependent cell-mediated cytotoxicity in vivo, modulating the activity of FcgammaRIII on effector cells. Although many mechanisms have been proposed to account for the anti-tumor activities of therapeutic antibodies, including extended half-life, blockade of signaling pathways, activation of apoptosis and effector-cell-mediated cytotoxicity, we show here that engagement of Fcgamma receptors on effector cells is a dominant component of the in vivo activity of antibodies against tumors. Mouse monoclonal antibodies, as well as the humanized, clinically effective therapeutic agents trastuzumab (Herceptin(R)) and rituximab (Rituxan(R)), engaged both activation (FcgammaRIII) and inhibitory (FcgammaRIIB) antibody receptors on myeloid cells, thus modulating their cytotoxic potential. Mice deficient in FcgammaRIIB showed much more antibody-dependent cell-mediated cytotoxicity; in contrast, mice deficient in activating Fc receptors as well as antibodies engineered to disrupt Fc binding to those receptors were unable to arrest tumor growth in vivo. These results demonstrate that Fc-receptor-dependent mechanisms contribute substantially to the action of cytotoxic antibodies against tumors and indicate that an optimal antibody against tumors would bind preferentially to activation Fc receptors and minimally to the inhibitory partner FcgammaRIIB.
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PMID:Inhibitory Fc receptors modulate in vivo cytotoxicity against tumor targets. 1074 35

In September 1998 Trastuzumab (Herceptin) became the second monoclonal antibody approved for the treatment of a malignant condition, and the first antibody approved for the treatment of a solid tumor. It is a mouse-human chimeric antibody that produces anti-tumor effects by blocking the HER2-neu receptor, and can also interact with human immune cells to effect antibody dependent cell-mediated cytotoxicity. Pivotal trials in breast cancer showed that it has activity as a single agent in a subset of patients whose tumors greatly over-express HER2, but results were even more impressive when it was used in combination with chemotherapy. It should also prove to be useful in the treatment of subsets of patients with other adenocarcinomas whose tumors over-express HER2.
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PMID:Perceptions of Herceptin: a monoclonal antibody for the treatment of breast cancer. 1085 Feb 81

HER-2/neu is a 185 kDa glycoprotein related to the epidermal growth factor receptor. Overexpressed in 25-30% of primary breast carcinomas, HER-2/neu is associated with a poor clinical outcome. Recently the FDA approved an antibody to HER-2/neu, trastuzumab (Herceptin), for the treatment of HER-2/neu overexpressing metastatic breast cancers. Relatively little is known about HER-2/neu status and lung cancers. We reasoned that if HER-2/neu status could be ascertained in non-small cell lung carcinomas (NSCLCs), and a clinical correlation can be established, a rationale for the use of Herceptin in this tumor type could be established. Using a FDA-approved standardized diagnostic kit, HercepTest, for detection of HER-2/neu in clinical specimens, we examined the expression of HER-2/neu in NSCLCs in archival paraffin-embedded specimens (N = 81). In normal epithelium, HER-2/neu expression was not detected in a majority of samples (74/81). HER-2/neu overexpression was detected in 27% of the tumors of different histological types including adenocarcinomas, large cell carcinomas, and squamous cell carcinomas. Poor to moderately differentiated, but not well differentiated tumors showed overexpression of HER-2/neu. The specificity of HercepTest was further increased (from 27% to 21%) when the expression in the few normal tissues was subtracted from the tumor score. HER-2/neu may offer an attractive predictive and prognostic factor for NSCLC.
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PMID:HER-2/neu expression in archival non-small cell lung carcinomas using FDA-approved Hercep test. 1092 58

Several recent advances have led to accelerated progress in breast cancer therapy. The development of new drugs with novel mechanisms of action, such as the taxanes, or oral bioavailability, such as capecitabine, has expanded the horizons of available chemotherapy. The use of tumor-related proteins or genes as markers of sensitivity or resistance to systemic therapy may allow for more predictable outcomes. Finally, the emergence of biological therapies such as the HER2/neu monoclonal antibody trastuzumab (Herceptin; Genentech, Inc, So. San Francisco, CA) represents an exciting new direction that opens doors to new concepts in antitumor therapy. This report will review the most exciting possibilities for expanding the field of breast cancer management.
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PMID:State-of-the-art chemotherapy for advanced breast cancer. 1104 51

The physical characteristics of tumor antigens that would make the most ideal targets for antibody therapeutics include cell surface expression; high, stable expression levels in tumor cells; low or absent expression in normal tissues; lack of a soluble form of the antigenic target; and lack of internalization of the antigen/antibody complex. HER2/neu is a 185-kd surface membrane protein that is overexpressed in approximately 25% of human breast cancers due to amplification of the HER2 gene. Overexpression of the gene results in ligand-independent activation of HER2 kinase, causing mitogenic signal transduction and increased cell proliferation. Consequently, patients with this alteration have a worse clinical prognosis. Trastuzumab (Herceptin; Genentech, Inc, So. San Francisco, CA), a humanized anti-HER2 monoclonal antibody, has significant clinical activity against metastatic breast cancers with HER2/neu overexpression, despite the fact that the p185HER2 protein product lacks some of the ideal characteristics of tumor antigens listed above. We propose that the efficacy of trastuzumab may be explained on the basis of its effects on signal transduction, which is independent from its immune mechanism(s) of action. Furthermore, trastuzumab is synergistic with some chemotherapeutic drugs, resulting in improved therapeutic efficacy. Thus, in the case of trastuzumab, a clear distinction may be drawn between the use of monoclonal antibodies as immuneactive agents and their use to achieve a desired cellular/biochemical activity.
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PMID:Biological rationale for HER2/neu (c-erbB2) as a target for monoclonal antibody therapy. 1104 52

Infiltrating pleomorphic lobular carcinoma (PLC) is an aggressive variant of infiltrating lobular carcinoma. Recently, in situ changes identical to PLC (PLCIS) have been described. The role of prognostic markers and their correlation with therapeutics, clinical outcome, and genetic changes is not well established in PLC. The authors examined 38 cases of this entity to understand better this tumor's biology. Immunohistochemical (IHC) analysis was performed in 21 specimens for estrogen and progesterone steroid receptors, p53, Her 2 (p185), and GCDFP-15. Genomic deoxyribonucleic acid was obtained from microdissected tumor as well as normal control cells, and loss of heterozygosity was investigated at the ESR (16q24), p53 (TP53 17p), Her 2 (17q 11-12), and BRCA 1 (17q12-25) loci. In this series, the average patient age was 57.5 years (age range, 24-92 years). Twenty-seven women were postmenopausal. Tumor size ranged from 1.2 to 25 cm. Six patients were a pathologic stage I; 19, stage II; 12, stage III; and one, stage IV. Histologically, multifocal nodular aggregates of discohesive pleomorphic tumor cells were seen interspersed in dense and fibrotic breast parenchyma. Twenty-nine percent of the specimens demonstrated associated signet ring cells. The remainder had dishesive, globoid, plasmacytoid cells with high-grade nuclear features. PLCIS was identified in 17 of 38 patients (45%), and lobular carcinoma in situ (LCIS) was noted in 8 patients (21%). IHC analysis showed estrogen immunoreactivity in 81%, progesterone in 67%, GCDFP-15 in 71%, and Her 2 in 81% (2+ to 3+ membranous staining) of specimens. Antibodies to p53 stained the tumor cell nuclei in 48% of the tumors. Loss of heterozygosity was identified in 52% of the specimens at the p53 locus, 18% at the ESR locus, 19% to 24% at the Her 2 loci, and 27% to 32% at the BRCA 1 locus. Follow-up was available in 19 patients and ranged from 12 months to 15 years (mean, 73 months). Seven patients had no evidence of disease at last examination (range, 1-15 years), three patients were alive with disease (range, 2-14 years), and nine patients were dead of disease (range, 2 months-9 years). Six patients had subsequent diagnoses of tumor in the contralateral breast. Analysis shows that PLC tends to appear in older postmenopausal women who present with locally advanced disease. PLCIS was found to be associated with PLC 45% of the time. The aggressive clinical course of patients with PLC is supported by tumor immunoreactivity with unfavorable markers Her 2 and p53. Overexpression of Her 2 in PLC may be therapeutically relevant, enabling the use of novel chemotherapeutic drugs like Herceptin. Interestingly, tumors that were Her 2 immunoreactive also maintained estrogen hormone immunoreactivity.
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PMID:Pleomorphic lobular carcinoma: morphology, immunohistochemistry, and molecular analysis. 1111 86

HER2 is a member of tyrosine kinase growth factor receptor family. When activated, it induces an intracellular phosphorylation cascade leading to an increased protein transcription and cellular growth. HER2 is overexpressed or amplified in 20 to 30% of invasive breast cancer where it plays an important role in the natural history of the disease. It is considered a poor prognostic factor and may also play a role as a predictive factor for response to therapy (potential resistance to hormonotherapy or CMF, sensitivity to anthracycline-based therapy). On the other hand, a monoclonal antibody, targetting specifically HER2, Herceptin (trastuzumab) has been developed and has shown a survival benefit in metastatic breast cancer strongly overexpressing HER2. Herceptin is actually "incorporated" in therapeutic algorithms for metastatic breast cancer and is evaluated in adjuvant settings. For all those reasons, the tumor HER2 status should probably be "routinely" tested in order to optimize the management of breast cancer patients. Nevertheless, some points remain to be elucidated, including the optimal methods of detection of HER2 (immunohistochemistry, Fish). One of the priorities for future research is to standardize HER2 testing, in order to reduce false-positive results and false-negative results and to better identify patients who are most likely going to benefit from Herceptin.
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PMID:[Breast cancer and herceptin]. 1112 93

HercepTestTM (DAKO A/S, Glostrup, Denmark) is an immunohistochemical assay that detects HER2/neu gene products, and evaluates the overexpression status of the HER2/neu protein in determining eligibility for the Trastuzumab (HerceptinR, Genentech, San Francisco, CA, USA) therapy. However, practically, interobserver variability of the HER2/neu interpretation of the immunostained results has caused marked disagreement with regard to the intensity of tumor staining. In this study, we quantitated HER2/neu expression by image analysis, and applied this analyzing system to help to minimize interobserver variability of the interpretation of the HercepTestTM. All the immunostained results were scored semiquantitatively on a range of 0 to 3+ in accordance with the criteria described as per the manufacturer's instructions, and quantitatively evaluated using an image analyzing system with image processing software. Among the 92 cases, 15 were scored as 3+, six were 2+, and 32 were 1+ under intraobservers agreement. When the cases were quantitated, a high correlation was shown between the signal area extracted by image analysis and the corresponding score of staining intensity with the HercepTestTM. By converting the quantitatively extracted data into a scoring system based upon the criteria, the outcome demonstrated a strong concordance with the scoring data obtained from immunostaining. The results indicated that a quantitative scoring system performed by simple image analysis may provide to improve interobserver agreement of the interpretation of the HercepTest TM in clinical practice.
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PMID:Quantitative immunohistochemical evaluation of HER2/neu expression with HercepTestTM in breast carcinoma by image analysis. 1114 61


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