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ABSTRACT: In the past 50years the equipment of operating rooms has changed enormously due to technological innovation and new surgery
methods. In particular the establishment of minimally invasive therapy has led to a considerable increase in equipment and
instruments that have to be used during surgery. The development of new equipment and instruments has had priority over the
past 10–15years, whereas now the manifold different equipment require systems integration and networking. Systems integration
and networking of different OR (operating room) system components are very important current technological challenges in operative
medicine. While certain technologies like robotic and navigation are still in the early stages, image documentation is an
excellent starting point for systems integration because of the advanced development stage and the need for all operative
disciplines. The Department of Obstetrics and Gynecology at the University of Tübingen in Germany (UFK) is delving into systems
integration and networking in the operating room. In addition to the central control and monitoring of different systems,
operating tables and lighting, the image documentation of intraoperative results is a principal topic. The UFK project is
part of the Center of Competence for Minimally Invasive Medicine and Technology Tübingen-Tuttlingen (MITT), which is promoted
by the German Federal Ministry of Education and Research. This article presents the importance and potential of systems integration
and networking in health care, the current stage of development and future trends, considering image documentation as an example.
Gynecological Surgery 04/2012; 3(1):6-11.
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ABSTRACT: With most ectopic pregnancy (EP) cases now diagnosed and treated early, a major concern has become future reproductive outcome. The aim of this study was to evaluate long-term reproductive outcome after salpingotomy versus salpingectomy in patients with and without additional fertility-reducing factors.
As part of a prospective follow-up study, 261 patients underwent laparoscopic management of EP at our institution. History was taken specifically looking at preexisting risk factors for reduced fertility. Patients were then followed with regard to future reproductive events.
Of 261 patients, 196 (75%) reported a subsequent desire for pregnancy. 145 patients had undergone salpingotomy and 51 salpingectomy. In patients without prior history of fertility-reducing factors, the subsequent intrauterine pregnancy rates were >90% for both salpingotomy and salpingectomy groups irrespective of the surgical approach. In patients with preexisting fertility-reducing factors, postoperative intrauterine pregnancy rates were 75% in the salpingotomy group, but only 40% in the salpingectomy group (p < 0.05), showing maximal effect for conservative surgery.
Laparoscopic salpingotomy is of particular benefit for patients with additional fertility-reducing factors desirous of future pregnancy. Reproductive outcome is excellent in patients without such risk factor, irrespective of the surgical approach.
Archives of Gynecology 11/2009; 283(1):41-5. · 0.91 Impact Factor
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Diane Palmieri,
Daniel Fitzgerald,
S Martin Shreeve,
Emily Hua,
Julie L Bronder,
Robert J Weil,
Sean Davis,
Andreas M Stark,
Maria J Merino, Raffael Kurek,
H Maximilian Mehdorn,
Gary Davis,
Seth M Steinberg,
Paul S Meltzer,
Kenneth Aldape,
Patricia S Steeg
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ABSTRACT: Brain metastases of breast cancer seem to be increasingin incidence as systemic therapy improves. Metastatic disease in the brain is associated with high morbidity and mortality. We present the first gene expression analysis of laser-captured epithelial cells from resected human brain metastases of breast cancer compared with unlinked primary breast tumors. The tumors were matched for histology, tumor-node-metastasis stage, and hormone receptor status. Most differentially expressed genes were down-regulated in the brain metastases, which included, surprisingly, many genes associated with metastasis. Quantitative real-time PCR analysis confirmed statistically significant differences or strong trends in the expression of six genes: BMP1, PEDF, LAMgamma3, SIAH, STHMN3, and TSPD2. Hexokinase 2 (HK2) was also of interest because of its increased expression in brain metastases. HK2 is important in glucose metabolism and apoptosis. In agreement with our microarray results, HK2 levels (both mRNA and protein) were elevated in a brain metastatic derivative (231-BR) of the human breast carcinoma cell line MDA-MB-231 relative to the parental cell line (231-P) in vitro. Knockdown of HK2 expression in 231-BR cells using short hairpin RNA reduced cell proliferation when cultures were maintained in glucose-limiting conditions. Finally, HK2 expression was analyzed in a cohort of 123 resected brain metastases of breast cancer. High HK2 expression was significantly associated with poor patient survival after craniotomy (P = 0.028). The data suggest that HK2 overexpression is associated with metastasis to the brain in breast cancer and it may be a therapeutic target.
Molecular Cancer Research 10/2009; 7(9):1438-45. · 4.29 Impact Factor
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Marcus M Schittenhelm,
Christian Kollmannsberger,
Karin Oechsle,
Amy Harlow,
Jason Morich,
Friedemann Honecker, Raffael Kurek,
Stephan Störkel,
Lothar Kanz,
Christopher L Corless,
Kwok-Kin Wong,
Carsten Bokemeyer,
Michael C Heinrich
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ABSTRACT: Antibodies targeting epidermal growth factor receptor (EGFR) have proven to be effective in patients with non-small cell lung cancer (NSCLC) that express EGFR. We recently published a phase I study of weekly matuzumab plus paclitaxel. This therapy was well tolerated and showed clinical responses in the majority of patients. Although matuzumab displays potent antitumor activity in some patients, not all patients respond well to treatment. Whether dysregulation of EGFR-mediated pathways precludes or sensitizes cells to paclitaxel is unknown. We sought to determine molecular predictive factors for therapy response in a phase I/II study patient cohort treated with matuzumab+/-paclitaxel. Twenty-three cases [including one complete response (CR), three partial responses (PR), 10 stable diseases (SD)] were screened using immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), PCR/sequencing and denaturing wave high performance liquid chromatography (D-HPLC) for expression, amplification, and mutation status of EGFR and downstream signaling pathways. All patients with PR or CR displayed an either high overall or single-cell EGFR expression in the majority of cells. In addition, all of the moderate responders, who achieved SD after at least two cycles of therapy, showed diffuse EGFR expression rates and/or strong single-cell EGFR expression. In contrast, 44% of the nonresponders showed low overall or single-cell EGFR expression levels. No low-expressing EGFR cases were present within the responder group. In addition, among patients with a gain-of-function mutation in KRAS primary therapy failure and/or short responses to therapy were observed. Our data suggest that EGFR expression and KRAS mutation status is predictive for clinical response to matuzumab +/- paclitaxel in patients with advanced NSCLC.
Molecular Cancer Therapeutics 04/2009; 8(3):481-9. · 5.23 Impact Factor
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Hans Neubauer,
Susan Clare,
Wojciech Wozny,
Gerhard Schwall,
Slobodan Poznanovic,
Werner Stegmann,
Ulrich Vogel,
Karl Sotlar,
Diethelm Wallwiener, Raffael Kurek,
Tanja Fehm,
Michael Cahill
Breast cancer research: BCR 02/2009; 11(1):401. · 5.24 Impact Factor
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Alexander Marmé,
Hans-Peter Zimmermann,
Gerhard Moldenhauer,
Marina Schorpp-Kistner,
Claudia Müller,
Olga Keberlein,
Antje Giersch,
Jürgen Kretschmer,
Brigitte Seib,
Eberhard Spiess,
Andreas Hunziker,
Faustino Merchán,
Peter Möller,
Uwe Hahn, Raffael Kurek,
Frederik Marmé,
Gunther Bastert,
Diethelm Wallwiener,
Herwig Ponstingl
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ABSTRACT: In a study on gene deregulation in ovarian carcinoma we found a mRNA coding for a 350 kDa protein, Drop1, to be downregulated 20- to 180-fold in the majority of ovarian and mammary carcinomas. The mRNA is encoded by a set of exons in the 5' region of the SYNE1 gene. Immunohistochemical staining for Drop1 protein by a specific monoclonal antibody corresponds to the pattern seen for the mRNA. cDNA arrays of matched pairs of tumor and normal tissue and in situ hybridizations confirmed the drastic loss of Drop1 mRNA as a common feature in uterus, cervix, kidney, lung, thyroid and pancreas carcinomas, already at early tumor stages and in all metastases. Two-hybrid studies suggest a role of this deficiency in the malignant progression of epithelial tumors.
International Journal of Cancer 12/2008; 123(9):2048-56. · 5.44 Impact Factor
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Hans Neubauer,
Susan E Clare,
Wojciech Wozny,
Gerhard P Schwall,
Slobodan Poznanovic,
Werner Stegmann,
Ulrich Vogel,
Karl Sotlar,
Diethelm Wallwiener, Raffael Kurek,
Tanja Fehm,
Michael A Cahill
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ABSTRACT: Breast tumors lacking the estrogen receptor-alpha (ER-alpha) have increased incidence of resistance to therapy and poorer clinical prognosis.
Whole tissue sections from 16 cryopreserved breast cancer tumors that were either positive or negative for the ER (eight ER positive and eight ER negative) were differentially analyzed by multiplex imaging of two-dimensional PAGE gels using 54 cm isoelectric focusing. Differentially detected spots of Progesterone Receptor Membrane Component 1 (PGRMC1) were shown to differ in phosphorylation status by differential two dimensional polyacrylamide gel electrophoresis of phosphatase-treated tumor proteins. Site directed mutagenesis was used to create putative phosphorylation site point mutants in PGRMC1. Stable transfectants of these mutants in MCF7 cells were assayed for their survival after oxidative stress, and for AKT kinase phosphorylation. Immune fluorescence using anti-PGRMC1 monoclonal antibody 5G7 was performed on breast cancer tissue microarrays.
Proteins significantly differentially abundant between estrogen receptor negative and estrogen receptor positive tumors at the 0.1% level were consistent with published profiles, suggesting an altered keratin pool, and increased inflammation and wound responses in estrogen receptor negative tumors. Two of three spots of PGRMC1 were more abundant in estrogen receptor negative tumors. Phosphatase treatment of breast tumor proteins indicated that the PGRMC1 isoforms differed in their phosphorylation status. Simultaneous mutation of PGRMC1 serine-56 and serine-180 [corrected] fully abrogated the sensitivity of stably transfected MCF7 breast cancer cells to peroxide-induced cell death. Immune fluorescence revealed that PGRMC1 was primarily expressed in ER-negative basal epithelial cells of mammary ductules. Even in advanced tumors, high levels of ER or PGRMC1 were almost mutually exclusive in individual cells. In five out of five examined ductal in situ breast cancers of comedo type, PGRMC1 was expressed in glucose transporter 1 negative or positive poorly oxygenated cells surrounding the necrotic core, surrounded by a more distal halo of ER-positive cells.
PGRMC1 phosphorylation may be involved in the clinical differences that underpin breast tumors of differing ER status.
Breast cancer research: BCR 11/2008; 10(5):R85. · 5.24 Impact Factor
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Diane Palmieri,
Julie L Bronder,
Jeanne M Herring,
Toshiyuki Yoneda,
Robert J Weil,
Andreas M Stark, Raffael Kurek,
Eleazar Vega-Valle,
Lionel Feigenbaum,
Douglas Halverson,
Alexander O Vortmeyer,
Seth M Steinberg,
Kenneth Aldape,
Patricia S Steeg
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ABSTRACT: Retrospective studies of breast cancer patients suggest that primary tumor Her-2 overexpression or trastuzumab therapy is associated with a devastating complication: the development of central nervous system (brain) metastases. Herein, we present Her-2 expression trends from resected human brain metastases and data from an experimental brain metastasis assay, both indicative of a functional contribution of Her-2 to brain metastatic colonization. Of 124 archival resected brain metastases from breast cancer patients, 36.2% overexpressed Her-2, indicating an enrichment in the frequency of tumor Her-2 overexpression at this metastatic site. Using quantitative real-time PCR of laser capture microdissected epithelial cells, Her-2 and epidermal growth factor receptor (EGFR) mRNA levels in a cohort of 12 frozen brain metastases were increased up to 5- and 9-fold, respectively, over those of Her-2-amplified primary tumors. Co-overexpression of Her-2 and EGFR was also observed in a subset of brain metastases. We then tested the hypothesis that overexpression of Her-2 increases the colonization of breast cancer cells in the brain in vivo. A subclone of MDA-MB-231 human breast carcinoma cells that selectively metastasizes to brain (231-BR) overexpressed EGFR; 231-BR cells were transfected with low (4- to 8-fold) or high (22- to 28-fold) levels of Her-2. In vivo, in a model of brain metastasis, low or high Her-2-overexpressing 231-BR clones produced comparable numbers of micrometastases in the brain as control transfectants; however, the Her-2 transfectants yielded 3-fold greater large metastases (>50 microm(2); P < 0.001). Our data indicate that Her-2 overexpression increases the outgrowth of metastatic tumor cells in the brain in this model system.
Cancer Research 06/2007; 67(9):4190-8. · 7.86 Impact Factor
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ABSTRACT: Breast cancer is one of the most common cancers observed in women in industrialized Western countries. The development of novel diagnostic methods and the application of modern systemic therapies have significantly optimized early detection and therapy of breast cancer. However, many patients are currently overtreated. Traditionally, tumours have been categorized on the basis of histopathological criteria. However, staining pattern and intensity of cancer cells are not sufficient to reflect the molecular events driving tumour development and progression. Therefore, new genomic, transcriptomic and proteomic techniques are applied to clinical samples aiming to identify new targets for a therapy tailored for an individual patient. After an introduction to common genomic and transcriptomic profiling technologies and their relevance for clinical use, we will focus on analytical and preanalytical applications for the identification of new therapeutic targets by protein profiling, with a special emphasis on two-dimensional gel-technologies (2D-PAGE), particularly as they apply to the study of breast cancer.
Recent results in cancer research. Fortschritte der Krebsforschung. Progrès dans les recherches sur le cancer 02/2007; 176:89-120.
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Raffael Kurek,
Robin Babel,
Susan Clare,
Andrea Endress,
Victor Faessler,
Olaf Fischbach,
Michael Keckeisen,
Harald Loeffler,
Hans Neubauer,
Erich Solomayer,
Diethelm Wallwiener,
Tanja Fehm
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ABSTRACT: The introduction of databases in clinics is increasingly important for the optimization of documentation, quality assurance,
improved patient care, reliable results and control of costs. Hence, database systems are not only important for bioinformatic
data analysis but are required to develop a successful experimental design. In spite of complex database structures and functions,
to date no available database alone satisfies all medical requirements. In the field of oncology special databases are needed
to manage tissue banks for oncological research and care. The interdisciplinary tumor database “TumorAGENT” has been developed
to manage patient and tumor sample data to enable medical research and in this way provides an important tool for genome and
proteome analysis of tumors. TumorAGENT is a web application developed on IEEE-standard and includes all medically relevant
data protection measures. The output languages are German and English. TumorAGENT is a database designed for breast carcinomas
and is fully operational since July 2005. Expansion to other malignancies as well as interconnection to molecular biological
databases is anticipated in database structure and program logic. Future plans are to upgrade TumorAGENT to manage other tumor
entities.
12/2006: pages 413-416;
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Hans Neubauer,
Susan E Clare, Raffael Kurek,
Tanja Fehm,
Diethelm Wallwiener,
Karl Sotlar,
Alfred Nordheim,
Wojciech Wozny,
Gerhard P Schwall,
Slobodan Poznanović,
Chaturvedula Sastri,
Christian Hunzinger,
Werner Stegmann,
André Schrattenholz,
Michael A Cahill
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ABSTRACT: The presence of progesterone receptor (PR) in estrogen receptor (ER)-positive breast cancer is associated with a good prognosis, and indicates that tumors are likely to respond to tamoxifen. However, ER+/PR- tumors respond less well. To reveal the potential molecular mechanism of this phenomenon, we sought to identify differential protein abundances between invasive ductal carcinoma cells from cryopreserved ER+/PR+ and ER+/PR- mammary tumor specimens. Because current proteomics methods are hampered in the examination of most primary human tumor samples by the extreme tissue heterogeneity, we used laser capture microdissection (LCM) to isolate tumor cells and developed a sample pooling strategy to analyze small sample protein lysates. Proteins from LCM-harvested tumors were pooled into four sub-pools from each condition of three tumors/sub-pool, and proteins from respective paired sub-pools were co-electrophoresed by 2-DE using 54-cm IEF over pH 4-9. Abundance ratios were accurately quantified by a differential multiplex radioactive ProteoTope method at low attomole levels ( approximately 3.6 microg protein per labeling reaction, <180 ng per multiplex protein sample per 54-cm gel). Applying this approach, differentially displayed proteins were identified by MS using comigrating non-radioactively labeled tumor proteins. They include decreased cytochrome b5 and transgelin, and more abundant CRABP-II, cyclophilin A, Neudesin, and hemoglobin in ER+/PR+ tumors versus ER+/PR- providing a possible explanation for differential susceptibility against tamoxifen as a result of deregulated cytochrome b5-dependent metabolism. This study demonstrates the potential of ProteoTope and LCM to enable extremely sensitive and precise differential analyses from well-defined primary clinical specimen.
Electrophoresis 06/2006; 27(9):1840-52. · 3.30 Impact Factor
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Christina S Schuetz,
Michael Bonin,
Susan E Clare,
Kay Nieselt,
Karl Sotlar,
Michael Walter,
Tanja Fehm,
Erich Solomayer,
Olaf Riess,
Diethelm Wallwiener, Raffael Kurek,
Hans J Neubauer
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ABSTRACT: Becoming invasive is a crucial step in breast cancer oncogenesis. At this point, a lesion carries the potential for spreading and metastasis--a process, whose molecular characteristics still remain poorly understood. In this article, we describe a matched-pair analysis of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) of nine breast ductal carcinomas to identify novel molecular markers characterizing the transition from DCIS to IDC. The purpose of this study was to better understand the molecular biology of this transition and to identify candidate genes whose products might serve as prognostic markers and/or as molecular targets for treatment. To obtain cellular-based gene expression profiles from epithelial tumor cells, we combined laser capture microdissection with a T7-based two-round RNA amplification and Affymetrix oligonucleotide microarray analysis. Altogether, a set of 24 tumor samples was analyzed, comprised of nine matched DCIS/IDC and replicate DCIS/IDC preparations from three of the nine tumors. Cluster analysis on expression data shows the robustness and reproducibility of the techniques we established. Using multiple statistical methods, 546 significantly differentially expressed probe sets were identified. Eighteen candidate genes were evaluated by RT-PCR. Examples of genes already known to be associated with breast cancer invasion are BPAG1, LRRC15, MMP11, and PLAU. The expression of BPAG1, DACT1, GREM1, MEF2C, SART2, and TNFAIP6 was localized to epithelial tumor cells by in situ hybridization and/or immunohistochemistry, confirming the accuracy of laser capture microdissection sampling and microarray analysis.
Cancer Research 06/2006; 66(10):5278-86. · 7.86 Impact Factor
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ABSTRACT: Neoadjuvant chemotherapy has been employed increasingly in operable breast cancer during recent years. Several randomized trials showed that the chances of breast conserving therapy are being enhanced, and that survival was not compromised by primary systemic therapy compared to adjuvant treatment. Apart from the surgical advantages of tumor downstaging and breast conservation, therapy upfront might offer the chance to predict subsequent response of an individual patient to a given agent in the adjuvant setting. Furthermore, by investigating pre- and posttreatment tumor specimens, the neaodjuvant setting might help to evaluate new predictive biological markers, assess biologic effects of new treatments, and gain insight into molecular mechanisms. For postmenopausal patients with receptor-positive disease who cannot tolerate the toxicities of chemotherapy regimens or are not eligible for immediate surgery, endocrine treatment is emerging as an attractive alternative in the neoadjuvant setting. The new third-generation aromatase inhibitors letrozole and anastrozole have been compared to tamoxifen in 3 well-designed randomized neoadjuvant phase III trials (PO24, IMPACT, and PROACT). These studies showed significantly higher response rates for letrozole than for tamoxifen, and comparable ones for anastrozole. Thus, the primary use of an aromatase inhibitor seems a feasible and safe treatment option for postmenopausal women with early-stage breast cancer who do not wish to or are unable to undergo immediate surgery or preoperative chemotherapy. Further neoadjuvant endocrine trials should help us to elucidate the cross-talk between the different signal transduction pathways and their role in endocrine resistance.
Clinical Breast Cancer 01/2005; 5(5):341-7. · 2.38 Impact Factor
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Eva Tolosa,
Weijie Li,
Yoshiyuki Yasuda,
Wolfgang Wienhold,
Lisa K Denzin,
Alfred Lautwein,
Christoph Driessen,
Petra Schnorrer,
Ekkehard Weber,
Stefan Stevanovic, Raffael Kurek,
Arthur Melms,
Dieter Bromme
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ABSTRACT: Stepwise degradation of the invariant chain (Ii) is required for the binding of antigenic peptides to MHC class II molecules. Cathepsin (Cat) L in the murine thymus and Cat S in peripheral APCs have both been implicated in the last step of Ii degradation that gives rise to the class II-associated invariant chain peptides (CLIP). Cat V has been recently described as highly homologous to Cat L and exclusively expressed in human thymus and testis, but with no mouse orthologue. We report that Cat V is the dominant cysteine protease in cortical human thymic epithelial cells, while Cat L and Cat S seem to be restricted to dendritic and macrophage-like cells. Active Cat V in thymic lysosomal preparations was demonstrated by active-site labeling. Recombinant Cat V was capable of converting Ii into CLIP efficiently, suggesting that Cat V is the protease that controls the generation of alphabeta-CLIP complexes in the human thymus, in analogy to Cat L in mouse. Comparison of Cat V expression between thymi from patients with myasthenia gravis and healthy controls revealed a significantly higher expression level in the pathological samples, suggesting a potential involvement of this protease in the immunopathogenesis of myasthenia gravis, an autoimmune disease almost invariably associated with thymic pathology.
Journal of Clinical Investigation 09/2003; 112(4):517-26. · 15.39 Impact Factor
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Julia D Wulfkuhle,
Dennis C Sgroi,
Henry Krutzsch,
Kelley McLean,
Kelly McGarvey,
Melodie Knowlton,
She Chen,
Hongjun Shu,
Aysegul Sahin, Raffael Kurek,
Diethelm Wallwiener,
Maria J Merino,
Emanuel F Petricoin,
Yingming Zhao,
Patricia S Steeg
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ABSTRACT: We report the first proteomic analysis of matched normal ductal/lobular units and ductal carcinoma in situ (DCIS) of the human breast. An understanding of the transition from normal epithelium to the first definable stage of cancer at the functional level of protein expression is hypothesized to contribute to improved detection, prevention, and treatment. Ten sets of two-dimensional gels were evaluated, containing either matched normal ductal/lobular units or DCIS from either whole tissue sections or up to 100,000 laser capture microdissected epithelial cells. Differential protein expression was confirmed by image analysis. Protein spots (315) were excised and subjected to mass spectrometry sequencing. Fifty-seven proteins were differentially expressed between normal ductal/lobular units and DCIS. Differences in overall protein expression levels and posttranslational processing were evident. Ten differentially expressed proteins were validated in independent DCIS specimens, and 14 of 15 proteomic trends from two-dimensional gel analyses were confirmed by standard immunohistochemical analysis using a limited independent tumor cohort. Many of the proteins identified were previously unconnected with breast cancer, including proteins regulating the intracellular trafficking of membranes, vesicles, cancer preventative agents, proteins, ions, and fatty acids. Other proteomic identifications related to cytoskeletal architecture, chaperone function, the microenvironment, apoptosis, and genomic instability. Proteomic analysis of DCIS revealed differential expression patterns distinct from previous nucleic acid-based studies and identified new facets of the earliest stage of breast cancer progression.
Cancer Research 12/2002; 62(22):6740-9. · 7.86 Impact Factor
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Toni Weinschenk,
Cécile Gouttefangeas,
Markus Schirle,
Florian Obermayr,
Steffen Walter,
Oliver Schoor, Raffael Kurek,
Wolfgang Loeser,
Karl-Horst Bichler,
Dorothee Wernet,
Stefan Stevanović,
Hans-Georg Rammensee
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ABSTRACT: Our aim is to identify as many candidates as possible for tumor-associated T-cell epitopes in individual patients. First, we performed expression profiling of tumor and normal tissue to identify genes exclusively expressed or overexpressed in the tumor sample. Then, using mass spectrometry, we characterized up to 77 different MHC ligands from the same tumor sample. Several of the MHC ligands were derived from overexpressed gene products, one was derived from a proto-oncogene, and another was derived from a frameshift mutation. At least one was identified as an actual T-cell epitope. Thus, we could show that by combining these two analytic tools, it is possible to propose several candidates for peptide-based immunotherapy. We envision the use of this novel integrated functional genomics approach for the design of antitumor vaccines tailored to suit the needs of each patient.
Cancer Research 11/2002; 62(20):5818-27. · 7.86 Impact Factor
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ABSTRACT: Phenobarbital (PB) is an antiepileptic drug that promotes hepatocarcinogenesis in rodents when administered subsequent to an initiating carcinogen like N-nitrosodiethylamine (DEN). In the mouse, the promotional effect of PB on liver tumor development results from a selective stimulation of clonal outgrowth of hepatocytes harboring activating mutations in the beta-catenin gene. Because glutamine synthetase (GS) has recently been shown to be a putative transcriptional target of beta-catenin, expression of GS during PB-mediated promotion of mouse hepatocarcinogenesis was investigated. Preneoplastic and neoplastic liver lesions were induced in 6-week-old male mice by a single injection of 90 micro g/g body weight of DEN, and groups of mice were subsequently kept on PB-containing (0.05%) or control diet for 39 weeks. In PB-treated mice, 46 of 51 lesions ( approximately 90%) were GS-positive in contrast to only 16 of 46 ( approximately 35%) in mice not treated with PB. Approximately 33% of liver was occupied by neoplastic tissue in PB-treated mice, of which >80% was GS positive. By contrast, only approximately 3.5% of liver consisted of neoplastic tissue in mice treated with DEN only, and approximately 25% of this was GS positive. We have previously shown that beta-catenin mutations are present in approximately 80% of liver tumors from PB-treated mice but are absent in liver tumors from mice treated with DEN only. By analyzing a panel of larger liver tumors, we now observed that tumors harboring beta-catenin mutations were GS positive, whereas tumors without beta-catenin mutations were GS negative. Similarly, tumors from an additional mouse carcinogenicity experiment where PB inhibited rather than promoted hepatocarcinogenesis were mostly GS negative. These data suggest that promotion of hepatocarcinogenesis by PB confers beta-catenin-mutated tumor cells with a selective advantage by up-regulation of GS expression.
Cancer Research 10/2002; 62(20):5685-8. · 7.86 Impact Factor
