Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:5.99.1.2 (topoisomerase)
 9,166 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the past 30 years, important advances have been made in the knowledge of breast cancer biology and in the treatment of the disease. However, the translation of these advances into clinical practice has been slow. With the advent of molecular-based medicine, it is hoped that the bridge between the bench and the bedside will continue to be shortened. Because breast cancer is a heterogeneous disease with wide-ranging subsets of patients who have different prognoses and who respond differently to treatments, the identification of patients who need treatment and the definition of the best therapy for an individual have become the priorities in breast cancer care. This article will review the crucial role of prognostic and predictive factors in achieving these goals. A critical review of classical and newer individual molecular markers, such as hormone receptors, HER2, urokinase-type plasminogen activator and plasminogen activator inhibitor 1, cyclin E, topoisomerase II, and p53, was performed, and the preliminary results obtained using the new gene expression profiling technology are described along with their potential clinical implications.
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PMID:Bringing molecular prognosis and prediction to the clinic. 1589 74

The purpose of this study was to evaluate amplification of topoisomerase IIalpha (TOP2A) and HER2 genes as predictors of response to chemotherapy in advanced breast cancer. Gene copy number of TOP2A and HER2 were analysed with chromogenic in situ hybridization (CISH) on paraffin-embedded tissue sections from the primary tumour of 85 patients treated with anthracycline containing chemotherapy. TOP2A gene amplification was present in 14 (16%) and HER2 gene amplification in 38 (45%) of the primary tumours. Two of the 14 cases with TOP2A amplification were amplified without concurrent HER2 amplification. Neither TOP2A nor HER2 gene amplification were significantly associated with response to chemotherapy (p = 0.35 and p = 0.49, respectively).
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PMID:TOP2A and HER2 gene amplification as predictors of response to anthracycline treatment in breast cancer. 1686 74

The aim of this study was to evaluate the association between immunohistochemical expression of topoisomerase IIalpha, HER2 and hormone receptors and response to primary anthracycline-based chemotherapy in locally advanced breast cancer. We analyzed 109 medical charts of patients treated with primary anthracycline-based chemotherapy in the Women's Integral Health Care Center from 1996 to 2004. The clinical and pathological response to primary chemotherapy was associated with topoisomerase Ilalpha and HER2 expression and hormone receptor negativity. Statistical analysis was performed using chi-squared, Fisher's exact test and Mann-Whitney test. No statistical association between clinical response and expression of topoisomerase Ilalpha, HER2 and hormone receptor negativity was found. However, there was an association between complete pathological response and hormone receptor negativity (P = 0.0289). The present study suggested that these markers should not be considered predictors of response to primary anthracycline-based chemotherapy, and prospective studies must be designed for this purpose.
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PMID:Association between immunohistochemical expression of topoisomerase IIalpha, HER2 and hormone receptors and response to primary chemotherapy in breast cancer. 1686 40

This years ASCO-meeting reinforced the trend of the recent years to get off from empirical treatment concepts to tailored and individualized diagnostics and therapy. However, the basis for an individual therapy is a specific molecular diagnostic which can be reflected in the analysis of hormonal receptor, HER-1, HER-2 and topoisomerase IIalpha in breast cancer. All these markers are not only able to prognosticate the course of disease but they also can predict the success of specific treatment approaches. Trastuzumab is standard therapy in HER-2 positive breast cancer both in the adjuvant and palliative setting. But new therapeutic agents, as e. g. lapatinib, are promising in the treatment of HER-2 positive breast cancer even if trastuzumab is failing. Otherwise it might possibly be an alternative option but adequate clinical results have to be awaited. The targeted inactivation of EGFR-related signal transduction pathways by e. g. gefitinib did not show a substantial improvement neither as a single agent nor in combination with endocrine treatment. However, the appropriate subgroup which might benefit from this therapy has to be defined even if molecular data suggest that patients with ER positive and PR negative breast cancer might be such a group. The increasing knowledge in terms of the biology of bone metastasis led to the development of new treatment options as e. g. denosumab, a humanized monoclonal antibody for RANK ligand. Two adjuvant cytotoxic treatment trials revealed that taxanes improve the prognosis of node positive breast cancer and should be administered sequentially. The advantage of switching to an aromatase inhibitor after two to three years of tamoxifen in endocrine treatment of postmenopausal patients is proved by two clinical trials (IES, ARNO) which could demonstrate a survival benefit. In conclusion it seems to be evident that new targeted therapy options are effective and will set new standards for the treatment of breast cancer patients in the near future. The presentation for the ovarian cancer focused on the addition of a third cytotoxic agent to carboplatin and paclitaxel as the standard therapy for the primary treatment of ovarian cancer. New data of Bevacizumab in the treatment of primary and recurrent ovarian cancer were presented. However, this is not yet a standard treatment for all patients and needs further investigations within large, multicentre, randomised trials. The lymphonodectomy as part of the primary therapy of the endometrial cancer seems to be a benefit at least in patients with advanced disease or high risk stage I tumours. The adjuvant therapy of uterine sarcomas is still not yet very well investigated and clear. A trial which recruited 12 years demonstrated a benefit in overall survival which has to be interpreted with caution. In this year again there have been registered an increasing number of interesting contributions from Germany, which also received international attention.
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PMID:[Molecular diagnostic and targeted therapy--"Barking dogs are going to bite": presentations from the 42nd Annual Meeting of the American Society of Clinical Oncology, Atlanta 2006]. 1700 57

Gene expression analysis in breast cancer patients undergoing neoadjuvant chemotherapy is an interesting tool for identification of gene signatures and new markers to predict tumor response. However, the detection of predictive markers strongly depends on the drugs used in the specific therapeutic setting. There is growing evidence that topoisomerase II-alpha (TOPO IIalpha) is a marker for anthracycline-, and microtubule-associated protein tau (MAPT) for taxane sensitivity. HER-2 has been described as a marker of both anthracycline and taxane sensitivity. We performed gene expression profiling of 50 patients within the GEPARTRIO study, an anthracycline and taxane neoadjuvant chemotherapy trial. Here we investigate the predictive value of TOPO IIalpha, MAPT and HER-2 mRNA expression for pathological complete response (pCR) in this setting. Interestingly, HER-2 gene expression was strongly predictive of pCR (P=0.017) as well as overall response (P=0.037) and clinical complete response (cCR, P=0.050). In contrast, for both TOPO IIalpha and MAPT no correlation with pCR was observed in our sample group.
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PMID:Gene expression profiling of breast cancer patients treated with docetaxel, doxorubicin, and cyclophosphamide within the GEPARTRIO trial: HER-2, but not topoisomerase II alpha and microtubule-associated protein tau, is highly predictive of tumor response. 1701 Jun 9

The HER-2 (also known as ERBB2/ErbB2/c-erbB2/HER-2/neu) oncogene is the most frequently amplified oncogene in breast cancer and is also amplified in other forms of cancer. Beside its important role in tumor induction, growth and progression, HER-2 is also a target for new therapeutic approaches such as Herceptin (trastuzumab), a recombinant antibody designed to block signaling through the HER-2 receptor. In addition to Herceptin, which is in a wide clinical use for HER-2 amplified breast cancer, a number of various HER-2 directed immunological and genetic strategies, either targeting the HER-2 receptor, its signaling pathways or both HER-2 and epidermal growth factor receptor (EGFR) simultaneously, have demonstrated promising pre-clinical activity in HER-2 amplified carcinomas. Moreover, the HER-2 amplicon is known to contain more than 30 genes with altered copy numbers that could be therapeutic targets for chemotherapy. The topoisomerase IIalpha 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 a great majority of HER-2 amplified primary breast tumors and also in tumors without HER-2 amplification. Recent experimental as well as numerous, large, multi-center trials suggest that amplification (and/or deletion) of TOP2A may account for both sensitivity or resistance to commonly used cytotoxic drugs, i.e. topoII-inhibitors (anthracyclines etc.), 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, and a number of therapeutic strategies targeting either the HER-2 or its signaling pathways in cancer therapy are being investigated. Combining HER-2 targeting therapies with conventional forms of cytotoxic chemotherapy, where additional diagnostic tests such as those ascertaining TOP2A status, may be helpful for the ideal selection of patients for the combination therapy of an HER-2 targeting drug together with a cytotoxic drug such as topoII-inhibitor especially in the case of TOP2A amplification.
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PMID:Simultaneous amplification of HER-2 (ERBB2) and topoisomerase IIalpha (TOP2A) genes--molecular basis for combination chemotherapy in cancer. 1710 May 65

Her2 and topoisomerase-IIalpha (T2A) gene amplification are separate events, although the latter is more frequently seen in Her2 amplified (34-90%) than in Her2 non-amplified (5-10%) tumours. There is a better correlation between Her2 amplification and protein overexpression in breast cancer (BC) than in other tumour types. This marker is also considered a powerful prognostic factor in BC, with similar data emerging in other solid tumours such as bladder, ovarian, endometrial, gastro-oesophageal and non-small cell lung cancer. Her2 amplification and/or overexpression are highly predictive of response to HER2-targeted compounds such as trastuzumab and lapatinib but have been inconsistent predictors of response to cytotoxic chemotherapy. There is also evidence that these tumours are relatively resistant to anti-oestrogen therapy (tamoxifen) but not to oestrogen deprivation (e.g. with aromatase inhibitors). T2A aberrations are uncommon events in solid tumours, with an overall prevalence of approximately 10%. T2A amplification has shown inconsistent correlation with T2A protein expression in preclinical and clinical studies, mainly because non-genetic events such as proliferation rate can also affect protein expression. Expression of T2A protein has not been shown to reliably predict response to T2A inhibitors, despite the fact that this enzyme is the direct target for these compounds. In BC, T2A amplification appears to be a good predictor of response to anthracyclines, but these data are still in the process of validation. The significance of T2A deletions is currently under investigation, but contrary to what was previously thought, it may also predict benefit from treatment with T2A inhibitors. The prognostic significance of T2A aberrations is currently unknown.
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PMID:The 17q12-q21 amplicon: Her2 and topoisomerase-IIalpha and their importance to the biology of solid tumours. 1711 34

Ovarian cancer represents the fifth most frequent cause of death as a result of malignant processes after cancers of the breast, large intestine, lung and stomach. Owing to the localisation of ovarian cancer, approximately 75% of cases are diagnosed at the III and IV stages of advancement according to FIGO. Because of the advanced stage of the disease surgery has to be followed by chemotherapy in most cases of ovarian cancer and therefore resistance to cytostatic drugs represents a major clinical problem. The potential to predict the response to therapy with the use of cytostatic drugs would enable the most effective drugs to be applied in individual cases, thus improving the efficiency of the treatment and restricting the development of resistance to cytostatic drugs. In the present paper the progress made so far in the prediction of the clinical course of ovarian cancer is reviewed. The significance of the expression of the ATP-binding cassette (ABC) transporters is described, including P-glycoprotein and MRP2, the principal representatives of the protein group. The importance of disturbed control of apoptosis and the overexpression of HER-2 and topoisomerase 1A are also discussed. Two sections are devoted to the most recent studies in the biology of ovarian cancer, pangenomic studies on gene expression using DNA microarrays and aberrations of DNA methylation.
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PMID:Prediction of the response to chemotherapy in ovarian cancers. 1717 7

HER2 and TOP2A genes, located on 17q, can be coamplified in cancer. Overexpression of both genes has been reported in high-grade, androgen-resistant prostate cancer. Both genes have not been compared in a single prostate cancer study and the frequency of TOP2A amplifications in prostate cancer is unknown. Using tissue microarrays, we did immunohistochemistry and fluorescence in situ hybridization for HER2 and TOP2A in 100 prostate cancers (41 localized and 59 advanced) and 42 cases of benign prostatic hyperplasia (BPH). Amplification was defined as a target/centromere signal ratio of > or =1.5. HER2 immunohistochemistry was scored from 0 to 3+. Percentage nuclei staining for topoisomerase IIalpha (topoIIalpha) was recorded; overexpression was defined as > or =5% cells staining. Eighteen (31%) advanced prostate cancers showed topoIIalpha overexpression; 12 (26%) showed TOP2A low-level amplification; 9 (16%) expressed HER2; and 6 (13%) showed HER2 low-level amplification. No high-level amplification of either gene (target/centromere signal ratio of > or =3.0) was detected. TOP2A coexpression and coamplification were seen in 75% and 66% of HER2-positive cases, respectively. Localized prostate cancer or BPH showed no gene amplification or topoIIalpha overexpression. Gene amplification or overexpression correlated with high stage and Gleason score. The presence of TOP2A amplification in advanced cancer was associated with androgen resistance and decreased survival by multivariate analysis. This is the first study to document low-level TOP2A amplification in prostate cancer and an association with reduced survival. TOP2A amplification may occur with or without HER2 duplication and is often associated with topoIIalpha expression. Therapies directed against topoIIalpha (and HER2) in such patients may improve survival.
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PMID:Low-level TOP2A amplification in prostate cancer is associated with HER2 duplication, androgen resistance, and decreased survival. 1736 13

Nonsmall-cell lung cancer (NSCLC) is not generally a chemosensitive tumor, and the mechanism of resistance to the relevant anticancer drugs has not been fully elucidated. Solamargine (SM), the major steroidal glycoalkaloids extracted from the Chinese herb Solanum, inhibits the growth of human tumor cells. We have previously demonstrated that SM regulates tumor necrosis factor receptors (TNFRs)- and mitochondria-mediated pathways and sensitizes NSCLC cells to initiate apoptosis. Interestingly, this investigation reveals that SM up-regulated Fas expression and down-regulated the expression of HER2, whose overexpression is associated with resistance to drugs, and promotes chemotherapy-induced apoptosis in NSCLC A549 and H441 cells. After treatment with SM, the expression of HER2 mRNA was correlated with the expression of topoisomerase IIalpha (TOP2A) mRNA. The combinatory use of low concentrations of SM with low-toxic topoisomerase II inhibitor epirubicin accelerated apoptotic cell death. Therefore, the downregulation of the HER2 and TOP2A expression by SM with epirubicin may partially explain the SM and epirubicin cytotoxicity synergy effect in NSCLC. Results of this study suggest that SM induces Fas and TNFR-induced NSCLC cell apoptosis and reduces HER2 expression. These findings provide the synergistic therapeutic interaction between SM and epirubicin, suggesting that such combinations may be effectively exploited in future human cancer clinical trials.
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PMID:Solamargine upregulation of Fas, downregulation of HER2, and enhancement of cytotoxicity using epirubicin in NSCLC cells. 1763 97


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