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)

Protein tyrosine phosphorylation is a key regulator of cell growth regulation and, when aberrant, is linked with the process of oncogenic transformation. Since tyrosine phosphatases (PTP) reverse phosphorylation mediated by tyrosine kinases (PTK), it has been hypothesized, but insufficiently studied to date, that PTPs function as tumor suppressors. Alternatively, PTPs may augment signal transduction by repriming substrates. To begin to assess the role of PTPs in ovarian cancer cell growth regulation, PTP partial cDNAs were cloned from the OVCA 433 ovarian cancer cell line using RT/PCR and degenerate oligonucleotide primers for the PTP consensus domain. Thirteen partial cDNAs were isolated, the sequences of which, when compared to GenBank, suggested that they were derived from PTP family members. These included PTP-alpha, PTP-gamma, LAR, PTP-delta, T-cell PTP, PTP-2A(1D), PTP-1B, PTP-1C, PTP-H1, PTP-PEST, PTP-Gallus, and two isolates which potentially represent novel PTPs. Steady-state expression analyses revealed that PTP-1B expression was undetectable in normal epithelium but was expressed in four of five ovarian cancer cell lines. In contrast, the expression of two SH2-containing PTPs, PTP-1C and PTP-2A, was detected in the normal ovarian epithelium but lost from one or more ovarian cancer cell lines. Finally, PTP-1B, PTP-alpha, and PTP-H1 expression was increased following HER-2/neu transfection of ovarian cancer cell lines. These results suggest that both normal ovarian epithelial cells and ovarian cancer cells express multiple PTPs. Further, some PTPs are differentially expressed between normal ovarian epithelium and ovarian cancer cells. Intriguingly, the transfection and increased expression of the prognostically significant HER-2/neu PTK induced a selective increase in the expression of the PTP-alpha, PTP-1B, and PTP-H1 tyrosine phosphatases.
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PMID:Transfection of human ovarian cancer cells with the HER-2/neu receptor tyrosine kinase induces a selective increase in PTP-H1, PTP-1B, PTP-alpha expression. 862 39

The aim of the present study was to determine the activity of a combined regimen of mitoxantrone (DHAD) and ifosfamide (IFO) and identify clinical and biological factors with prognostic importance for the second-line treatment of ovarian cancer. The following factors were investigated for their prognostic importance: age, disease sites, platinum responsiveness, histological grade, the presence of clinically/radiologically detectable versus not detectable disease, residual disease volume after first surgery, p53 protein, c-erbB-2 oncoprotein and laminin receptor. 72 patients entered the trial. DHAD and IFO therapy led to a 15% response rate among the 47 cases with clinically/radiologically detectable disease (1 complete and 6 partial responses), with a median response duration of 4 months. The response rate was significantly different according to platinum responsiveness (4% objective responses in platinum-resistant versus 27% in platinum-sensitive disease). The time to treatment failure (TTF) and overall survival (OS) were affected by the presence of clinically detectable disease at study entry (median TTF 4 months in the presence of clinically/radiologically detectable disease versus 9 months if the disease was not similarly detectable, P = 0.02; median OS 10 months versus 21 months, P = 0.01). Initially overexpressed in only a few tumours, the c-erbB-2 oncoprotein became overexpressed in 36% of platinum-resistant tumours; this modulation did not occur in platinum-sensitive tumours. Furthermore, laminin receptor was expressed in 77% of platinum-sensitive versus 39% of platinum-resistant patients. There were no differences in p53 protein expression according to drug responsiveness.
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PMID:An I.T.M.O. group study on second-line treatment in advanced epithelial ovarian cancer: an attempt to identify clinical and biological factors determining prognosis. 865 51

The usefulness of prognostic factors in gynecological cancer was evaluated using the oncogenes, tumor suppressor genes and DNA viruses detected with the molecular biological technique. In uterine cervical cancer, HPV types 16 and 18 are considered to have a high oncogenic risk, and are commonly associated with high grade CIN and invasive cancer under persistent HPV infection. C-myc overexpression in advanced stage and p53 mutation in HPV negative case are associated with poor survival. In endometrial cancer, oncogene activation and expression are less frequent than in cervical and ovarian cancer. K-ras point mutation (codon 12) tumors are more aggressive and c-erbB-2 overexpression are associated with metastasis and poor survival. In ovarian cancer, there are numerous abnormalities of oncogenes and tumor suppressor genes. Especially, EGF-R and PDGF-R alpha expression are associated with decreased survival. p53 mutation also decreases survival and response to chemotherapy. Recently. MSH2 (Lynch II syndrome) and BRCA1 gene are known to relate with familial ovarian cancer.
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PMID:[Evaluation of prognostic factors in gynecological cancer examined by molecular biological study]. 868 14

Previous investigators have noted that certain ovarian cancer cell lines secrete and respond to transforming growth factor-alpha (TGF-alpha), suggesting that endogenous activation of the epidermal growth factor (EGF) receptor through autocrine or paracrine mechanisms might contribute to the proliferative response. In order to determine whether autocrine stimulation was partly responsible for the proliferative response in ovarian cancer, we investigated whether the EGF receptor expressed by ovarian cancer cell lines was constitutively activated as assessed by the presence of tyrosine phosphorylation. A specific anti-phosphotyrosine antibody was used in conjunction with an immunoblotting technique in order to detect EGF receptor phosphorylation in ovarian cancer cell lines in the absence and presence of exogenous EGF. The effects of neutralising anti-EGF receptor antibody on the proliferation of ovarian cancer cell lines was also examined. We found no evidence for constitutive tyrosine phosphorylation of the p170 EGF receptor in eight epithelial ovarian cancer cell lines tested, although each line demonstrated inducible phosphorylation in response to exogenous EGF. The absence of constitutive EGF receptor activation was also noted when cells were grown under high density conditions, thus excluding a role for membrane-bound EGF or TGF-alpha in this process. Media conditioned by five ovarian cancer cell lines, as well as malignant ascites obtained from 12 different ovarian cancer patients, were not capable of stimulating EGF receptor phosphorylation. Finally, the proliferation of ovarian cancer cell lines was not significantly inhibited in the presence of neutralising anti-EGF receptor antibody. These data suggest that EGF receptor activation through autocrine pathways is not a major mechanism for the growth of many ovarian cancer cell lines. Other pathways of signal transduction which bypass the requirement for EGF receptor activation may be important in the proliferation for ovarian cancer cells. Such EGF receptor-independent pathways may limit the effectiveness of strategies designed to inhibit ovarian cancer cell growth through disruption of EGF receptor function.
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PMID:Absence of constitutive EGF receptor activation in ovarian cancer cell lines. 869 62

Twenty-four advanced (surgical stage III and IV) ovarian carcinomas and 15 borderline ovarian tumours were studied for the overexpression of nm23 and HER-2/neu (c-erb-B2) by means of immunohistochemistry on sections from routinely processed, paraffin-embedded, archival tumour blocks, using the NCL-nm23 and the NCL-CB11 monoclonal antibodies and the streptavidin-biotin-peroxidase technique. Significantly more advanced ovarian carcinomas (p = 0.034) expressed high levels of nm23 when compared to borderline tumours. HER-2/neu (c-erb-B2) expression, as could be expected, was also significantly more frequent in advanced ovarian carcinomas (p = 0.006). We were not able to find the previously reported association between nm23 and HER-2/neu overexpression in our tumours. Our results on nm23 overexpression in ovarian cancer are coincident with those previously reported using nm23-mRNA measurements on fresh ovarian tissues. Thus, ovarian carcinoma seems to belong to the group of tumours, like colon carcinoma and neuroblastoma, in which nm23 overexpression is associated with a more malignant phenotype. Immunohistochemistry performed on archival samples from ovarian carcinomas seems adequate for the demonstration of nm23 overexpression in ovarian cancer. This opens the possibility for larger studies on series of patients with a closed follow-up, which could help to establish the role of this gene in this kind of tumour.
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PMID:nm23 expression in advanced and borderline ovarian carcinoma. 870 36

The HER-2/neu gene is frequently amplified and/or its protein product, p185, is overexpressed in a number of human cancers. Overexpression of p185 correlates with poor prognosis and low survival rates in ovarian cancer patients. We previously found that the K1 mutant of SV40 large T antigen inhibits rat neu promoter and suppresses mutation-activated rat neu transformation in mouse fibroblasts. We show here that K1 also inhibits human HER-2/neu promoter in human ovarian cancer cells. To investigate whether K1 can suppress HER-2/neu transformation and thus is a potential therapeutic agent, we used an orthotopic ovarian cancer model in which mice were injected intraperitoneally with HER-2/neu-overexpressing human ovarian cancer cells to induce tumor development. The tumor-bearing mice were then treated with K1-liposome complex weekly. We found that liposome-mediated K1 gene transfer decreased the p185 protein level by K1 expression in these cancer cells and significantly prolonged mice survival; about 40% of these treated mice were alive for more than 1 year without any tumor development. On the other hand, the animals from control groups that did not receive this gene therapy all developed tumors and died within 7 months. The results indicate that liposome-mediated K1 gene transfer is able to suppress tumor development from HER-2/neu-overexpressing ovarian cancer cells in mice.
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PMID:Mutant SV40 large T antigen as a therapeutic agent for HER-2/neu-overexpressing ovarian cancer. 872 81

Alterations in specific oncogenes and tumor suppressor genes that serve as surrogate markers of malignant transformation have been identified in ovarian cancers. Overexpression of the HER-2/neu oncogene occurs in approximately 30% of breast and ovarian cancers. In most studies, HER-2/neu overexpression has correlated with poor survival. Although mutation of the K-ras oncogene has been found in some mucinous ovarian cancers, mutations in this gene appear to be more common in borderline ovarian tumors. Amplification of c-myc occurs in approximately 30% of ovarian cancers and is more frequently seen in serous cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 50% of Stage III/IV and 15% of Stage I/II ovarian cancers. Most p53 mutations in ovarian cancers are transitions, which suggests that they arise spontaneously rather than due to exogenous carcinogens. In contrast to the acquired genetic alterations described above that are a feature of sporadic ovarian cancers, a small fraction of epithelial ovarian cancers arise due to inherited genetic defects. Recently, the BRCA1 tumor suppressor gene on chromosome 17q was identified and shown to be responsible for some cases of hereditary breast and ovarian cancer. Families in which mutations in this gene exist are usually characterized by early age of disease onset. Presently, it remains unclear what fraction of hereditary ovarian cancers are due to BRCA1 mutations.
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PMID:Biomarkers in the ovary. 874

The inability to identify relevant markers for presymptomatic screening in early stage or "preinvasive" ovarian cancer has plagued investigators and clinicians facing the problems of early detection. The characteristic late stage of disease at initial presentation has hindered our understanding of the biologic progression and stepwise molecular alterations that result in ovarian carcinoma. To date, most screening studies have focused on identifying early anatomic changes using ultrasound or fluctuations in serum biomarkers such as CA-125. These screening methodologies have proven inadequate in both sensitivity and specificity for early stage ovarian cancer detection. Molecular analysis of ovarian carcinomas has revealed alterations in oncogenes and tumor suppressor genes associated with these tumors. The HER-2/neu oncogene, a member of the epidermal growth factor family, is amplified or overexpressed in approximately 25-30% of ovarian carcinomas. Significant data substantiate an important role for HER-2/neu in the pathophysiology of ovarian cancer. While potentially an attractive surrogate endpoint biomarker (SEB), serum HER-2/neu levels have not proven to be a useful screening modality. In response to the urgent need for improved early detection for ovarian cancer, our current research efforts include differential hybridization studies between normal and malignant ovarian epithelium to define potentially unique ovarian cancer antigens which may ultimately have utility; defining physical alterations that occur in malignant ovarian tissues using implanted telemetry systems; studies using positron emission tomography to detect changes in glucose metabolism between normal and malignant ovarian tissues; and screening studies using a 3-dimensional ultrasound unit to improve the accuracy of this technique in recognizing early neoplastic changes. By taking diverse approaches to tackle this problem, an improved understanding of ovarian carcinogenesis should translate into the identification of appropriate SEBs for early detection.
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PMID:Screening for ovarian cancer: what are the optimal surrogate endpoints for clinical trials? 874 1

The oncogene specific mRNA of c-erbB-2 was detected by the S1 nuclease protection assay in 95 ovarian cancer specimens. In 79 primary carcinomas, we found 16 (20%) with strong expression, 13 (17%) with weak expression, 4 (5%) with very weak expression, and 46 (58%) with no expression. In 3 of 16 recurrencies (19%) a strong expression of c-erbB-2 mRNA was detected, in 2 (12%) weak expression was detected, and in 11 (69%) no expression of c-erbB-2 mRNA was detected. Kaplan-Meier analysis revealed no significant association between strong expression of c-erbB-2 mRNA and survival of the 79 patients with primary cancer. However, in the subgroup of patients with FIGO (International Federation of Gynecology and Obstetrics) stages III and IV (n = 60) a shorter median survival time (12 months) was obtained for patients with strong c-erbB-2 mRNA expression compared to patients with no, very weak, and weak c-erbB-2 mRNA expression (25 months, P = 0.04). In addition, strong expression of c-erbB-2 mRNA did not depend on histologic grade, histologic type, and FIGO stage. Adverse prognostic factors include histologic type (serous carcinoma), high grade, high stage (FIGO stages III and IV), and residual of tumor after surgery. From our results we conclude that for all patients (FIGO stages I-IV) strong expression of c-erbB-2 mRNA is not a prognostic parameter, but in the subpopulation of patients with FIGO stage III and IV only, an association between strong c-erbB-2 mRNA expression and shorter median survival time was found, although statistical significance was weak (P = 0.04).
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PMID:Prognostic significance of c-erB-2 mRNA in ovarian carcinoma. 875 60

The erbB-2 oncoprotein is overexpressed in 30% of tumors from breast and ovarian cancer patients and it is related to poor overall and disease-free survival. In vitro studies on erbB-2-overexpressing cells have found a strong correlation between this oncogene overexpression and relative resistance to lymphokine-activated killer (LAK) cell lysis. gp30/heregulin/NDF (neu differentiation factor), indirect activators of erbB-2, are able to induce a more differentiated phenotype on erbB-2-overexpressing, erbB-3- and/or erbB-4-positive breast cancer cells. We tested the ability of these highly homologous growth factors to stimulate LAK cell lysis of breast cancer cells. Our experiments demonstrated a marked increase in LAK cell cytotoxicity towards an erbB-2-overexpressing, erbB-3-positive cell line by treatment of these cells with heregulin for 72 h. In contrast we did not observe any enhancement of lysis of MCF-7, a cell line that does not overexpress erbB-2 and is positive for the erbB-3 and erbB-4 receptors, after treatment with heregulin. The increased lysis was associated with upregulation of intercellular adhesion molecule 1 (ICAM-1), down-regulation of erbB-2 and increased binding between breast cancer cells and LAK cells. Pre incubation of target (SKBR3) cells with blocking anti-ICAM-1 antibody completely abrogated the enhanced cytotoxicity. A similar effect was observed by pretreatment of the effector (LAK) cells with antibodies directed against LFA-1, the receptor for ICAM-1. These results suggest the possible utilization of gp30/heregulin in the treatment of breast cancer patients by its ability to stimulate patient immune responses.
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PMID:Heregulin induces increase in sensitivity of an erbB-2-overexpressing breast cancer cell type to lysis by lymphokine-activated killer cells. 891 31


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