TY - JOUR A1 - Martrat, Griselda A1 - Maxwell, Christopher A. A1 - Tominaga, Emiko A1 - Porta-de-la-Riva, Montserrat A1 - Bonifaci, Núria A1 - Gómez-Baldó, Laia A1 - Bogliolo, Massimo A1 - Lázaro, Conxi A1 - Blanco, Ignacio A1 - Brunet, Joan A1 - Neveling, Kornelia A1 - et al, T1 - Exploring the link between MORF4L1 and risk of breast cancer JF - Breast Cancer Research N2 - Introduction: Proteins encoded by Fanconi anemia (FA) and/or breast cancer (BrCa) susceptibility genes cooperate in a common DNA damage repair signaling pathway. To gain deeper insight into this pathway and its influence on cancer risk, we searched for novel components through protein physical interaction screens. Methods: Protein physical interactions were screened using the yeast two-hybrid system. Co-affinity purifications and endogenous co-immunoprecipitation assays were performed to corroborate interactions. Biochemical and functional assays in human, mouse and Caenorhabditis elegans models were carried out to characterize pathway components. Thirteen FANCD2-monoubiquitinylation-positive FA cell lines excluded for genetic defects in the downstream pathway components and 300 familial BrCa patients negative for BRCA1/2 mutations were analyzed for genetic mutations. Common genetic variants were genotyped in 9,573 BRCA1/2 mutation carriers for associations with BrCa risk. Results: A previously identified co-purifying protein with PALB2 was identified, MRG15 (MORF4L1 gene). Results in human, mouse and C. elegans models delineate molecular and functional relationships with BRCA2, PALB2, RAD51 and RPA1 that suggest a role for MRG15 in the repair of DNA double-strand breaks. Mrg15-deficient murine embryonic fibroblasts showed moderate sensitivity to g-irradiation relative to controls and reduced formation of Rad51 nuclear foci. Examination of mutants of MRG15 and BRCA2 C. elegans orthologs revealed phenocopy by accumulation of RPA-1 (human RPA1) nuclear foci and aberrant chromosomal compactions in meiotic cells. However, no alterations or mutations were identified for MRG15/MORF4L1 in unclassified FA patients and BrCa familial cases. Finally, no significant associations between common MORF4L1 variants and BrCa risk for BRCA1 or BRCA2 mutation carriers were identified: rs7164529, Ptrend = 0.45 and 0.05, P2df = 0.51 and 0.14, respectively; and rs10519219, Ptrend = 0.92 and 0.72, P2df = 0.76 and 0.07, respectively. Conclusions: While the present study expands on the role of MRG15 in the control of genomic stability, weak associations cannot be ruled out for potential low-penetrance variants at MORF4L1 and BrCa risk among BRCA2 mutation carriers. KW - breast cancer Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-169119 VL - 13 IS - R40 ER - TY - JOUR A1 - Diessner, Joachim A1 - Wischnewsky, Manfred A1 - Stüber, Tanja A1 - Stein, Roland A1 - Krockenberger, Mathias A1 - Häusler, Sebastian A1 - Janni, Wolfgang A1 - Kreienberg, Rolf A1 - Blettner, Maria A1 - Schwentner, Lukas A1 - Wöckel, Achim A1 - Bartmann, Catharina T1 - Evaluation of clinical parameters influencing the development of bone metastasis in breast cancer JF - BMC Cancer N2 - Background The development of metastases is a negative prognostic parameter for the clinical outcome of breast cancer. Bone constitutes the first site of distant metastases for many affected women. The purpose of this retrospective multicentre study was to evaluate if and how different variables such as primary tumour stage, biological and histological subtype, age at primary diagnosis, tumour size, the number of affected lymph nodes as well as grading influence the development of bone-only metastases. Methods This retrospective German multicentre study is based on the BRENDA collective and included 9625 patients with primary breast cancer recruited from 1992 to 2008. In this analysis, we investigated a subgroup of 226 patients with bone-only metastases. Association between bone-only relapse and clinico-pathological risk factors was assessed in multivariate models using the tree-building algorithms “exhausted CHAID (Chi-square Automatic Interaction Detectors)” and CART(Classification and Regression Tree), as well as radial basis function networks (RBF-net), feedforward multilayer perceptron networks (MLP) and logistic regression. Results Multivariate analysis demonstrated that breast cancer subtypes have the strongest influence on the development of bone-only metastases (χ2 = 28). 29.9 % of patients with luminal A or luminal B (ABC-patients) and 11.4 % with triple negative BC (TNBC) or HER2-overexpressing tumours had bone-only metastases (p < 0.001). Five different mathematical models confirmed this correlation. The second important risk factor is the age at primary diagnosis. Moreover, BC subcategories influence the overall survival from date of metastatic disease of patients with bone-only metastases. Patients with bone-only metastases and TNBC (p < 0.001; HR = 7.47 (95 % CI: 3.52–15.87) or HER2 overexpressing BC (p = 0.007; HR = 3.04 (95 % CI: 1.36–6.80) have the worst outcome compared to patients with luminal A or luminal B tumours and bone-only metastases. Conclusion The bottom line of different mathematical models is the prior importance of subcategories of breast cancer and the age at primary diagnosis for the appearance of osseous metastases. The primary tumour stage, histological subtype, tumour size, the number of affected lymph nodes, grading and NPI seem to have only a minor influence on the development of bone-only metastases. KW - BRENDA KW - breast cancer KW - bone metastases KW - skeleton KW - breast cancer subtypes Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161173 VL - 16 IS - 307 ER - TY - JOUR A1 - Stein, Roland Gregor A1 - Wollschläger, Daniel A1 - Kreienberg, Rolf A1 - Janni, Wolfgang A1 - Wischnewsky, Manfred A1 - Diessner, Joachim A1 - Stüber, Tanja A1 - Bartmann, Catharina A1 - Krockenberger, Mathias A1 - Wischhusen, Jörg A1 - Wöckel, Achim A1 - Blettner, Maria A1 - Schwentner, Lukas T1 - The impact of breast cancer biological subtyping on tumor size assessment by ultrasound and mammography - a retrospective multicenter cohort study of 6543 primary breast cancer patients JF - BMC Cancer N2 - Background Mammography and ultrasound are the gold standard imaging techniques for preoperative assessment and for monitoring the efficacy of neoadjuvant chemotherapy in breast cancer. Maximum accuracy in predicting pathological tumor size non-invasively is critical for individualized therapy and surgical planning. We therefore aimed to assess the accuracy of tumor size measurement by ultrasound and mammography in a multicentered health services research study. Methods We retrospectively analyzed data from 6543 patients with unifocal, unilateral primary breast cancer. The maximum tumor diameter was measured by ultrasound and/or mammographic imaging. All measurements were compared to final tumor diameter determined by postoperative histopathological examination. We compared the precision of each imaging method across different patient subgroups as well as the method-specific accuracy in each patient subgroup. Results Overall, the correlation with histology was 0.61 for mammography and 0.60 for ultrasound. Both correlations were higher in pT2 cancers than in pT1 and pT3. Ultrasound as well as mammography revealed a significantly higher correlation with histology in invasive ductal compared to lobular cancers (p < 0.01). For invasive lobular cancers, the mammography showed better correlation with histology than ultrasound (p = 0.01), whereas there was no such advantage for invasive ductal cancers. Ultrasound was significantly superior for HR negative cancers (p < 0.001). HER2/neu positive cancers were also more precisely assessed by ultrasound (p < 0.001). The size of HER2/neu negative cancers could be more accurately predicted by mammography (p < 0.001). Conclusion This multicentered health services research approach demonstrates that predicting tumor size by mammography and ultrasound provides accurate results. Biological tumor features do, however, affect the diagnostic precision. KW - histopathology KW - breast cancer KW - ultrasound KW - mammography KW - tumor size Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161050 VL - 16 IS - 549 ER - TY - JOUR A1 - Lv, Xiaoqun A1 - Zhang, Lingyun A1 - Zhu, Yanyan A1 - Said, Harun M. A1 - Shi, Jimin A1 - Xu, Guoxiong T1 - Regulative effect of Nampt on tumor progression and cell viability in human colorectal cancer JF - Journal of Cancer N2 - Colorectal cancer (CRC) is the third most common cancer disease. Here we examined Nampt expression in patients with CRC and the effect of Nampt on cell viability in CRC cells. Nampt protein was overexpressed in colorectal adenoma as well as colorectal carcinoma. The immunoreactive staining of Nampt was negative in the adjacent normal colorectal tissue, weak in colorectal adenoma, and strong in colorectal carcinoma, which may represent tumor progression. Further evaluation of clinical data showed that Nampt expression was not correlated with the clinicopathological characteristics of CRC. Additionally, our in vitro studies demonstrated that Nampt promotes CRC cell viability, whereas the Nampt inhibitor FK866 suppressed CRC cell viability, which was in concordance with the previous studies in other cancer cells. Treatment with Nampt-siRNA reduced the Nampt protein expression resulting in the inhibition of the cell viability of HCT116 and Caco2. Thus, the involvement of Nampt in cell growth indicates that Nampt may play an important role in colorectal tumorigenesis. As a consequence, our results suggest that Nampt may be considered as a progression marker of colorectal tumor and a potentially therapeutic target for the treatment of CRC. KW - nicotinamide phosphoribosyltransferase KW - signaling pathways KW - gastric cancer KW - overexpression KW - cell proliferation KW - tumor biomarker KW - adenocarcinoma KW - Nampt KW - visfatin KW - PBEF KW - breast cancer KW - prognostic value KW - visfatin levels KW - inhibitor KW - expression KW - adipocytokines Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-144516 VL - 6 IS - 9 ER - TY - JOUR A1 - Steinmann, Diana A1 - Paelecke-Habermann, Yvonne A1 - Geinitz, Hans A1 - Aschoff, Raimund A1 - Bayerl, Anja A1 - Bölling, Tobias A1 - Bosch, Elisabeth A1 - Bruns, Frank A1 - Eichenseder-Seiss, Ute A1 - Gerstein, Johanna A1 - Gharbi, Nadine A1 - Hagg, Juliane A1 - Hipp, Matthias A1 - Kleff, Irmgard A1 - Müller, Axel A1 - Schäfer, Christof A1 - Schleicher, Ursula A1 - Sehlen, Susanne A1 - Theodorou, Marilena A1 - Wypior, Hans-Joachim A1 - Zehentmayr, Franz A1 - van Oorschot, Birgitt A1 - Vordermark, Dirk T1 - Prospective evaluation of quality of life effects in patients undergoing palliative radiotherapy for brain metastases JF - BMC Cancer N2 - Background: Recently published results of quality of life (QoL) studies indicated different outcomes of palliative radiotherapy for brain metastases. This prospective multi-center QoL study of patients with brain metastases was designed to investigate which QoL domains improve or worsen after palliative radiotherapy and which might provide prognostic information. Methods: From 01/2007-01/2009, n=151 patients with previously untreated brain metastases were recruited at 14 centers in Germany and Austria. Most patients (82 %) received whole-brain radiotherapy. QoL was measured with the EORTC-QLQ-C15-PAL and brain module BN20 before the start of radiotherapy and after 3 months. Results: At 3 months, 88/142 (62 %) survived. Nine patients were not able to be followed up. 62 patients (70.5 % of 3-month survivors) completed the second set of questionnaires. Three months after the start of radiotherapy QoL deteriorated significantly in the areas of global QoL, physical function, fatigue, nausea, pain, appetite loss, hair loss, drowsiness, motor dysfunction, communication deficit and weakness of legs. Although the use of corticosteroid at 3 months could be reduced compared to pre-treatment (63 % vs. 37 %), the score for headaches remained stable. Initial QoL at the start of treatment was better in those alive than in those deceased at 3 months, significantly for physical function, motor dysfunction and the symptom scales fatigue, pain, appetite loss and weakness of legs. In a multivariate model, lower Karnofsky performance score, higher age and higher pain ratings before radiotherapy were prognostic of 3-month survival. Conclusions: Moderate deterioration in several QoL domains was predominantly observed three months after start of palliative radiotherapy for brain metastases. Future studies will need to address the individual subjective benefit or burden from such treatment. Baseline QoL scores before palliative radiotherapy for brain metastases may contain prognostic information. KW - breast cancer KW - brain tumours KW - survival KW - validation KW - symptoms KW - EORTC-QLQ-C15-PAL KW - EORTC-BN20 KW - whole-brain radiotherapy KW - partitioning analysis RPA KW - cancer patients KW - lung cancer KW - prognostic index KW - radiation oncology KW - clinical trials Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-135254 VL - 12 IS - 283 ER - TY - JOUR A1 - Peck, Barrie A1 - Schug, Zachary T. A1 - Zhang, Qifeng A1 - Dankworth, Beatrice A1 - Jones, Dylan T. A1 - Smethurst, Elizabeth A1 - Patel, Rachana A1 - Mason, Susan A1 - Jian, Ming A1 - Saunders, Rebecca A1 - Howell, Michael A1 - Mitter, Richard A1 - Spencer-Dene, Bradley A1 - Stamp, Gordon A1 - McGarry, Lynn A1 - James, Daniel A1 - Shanks, Emma A1 - Aboagye, Eric O. A1 - Critchlow, Susan E. A1 - Leung, Hing Y. A1 - Harris, Adrian L. A1 - Wakelam, Michael J. O. A1 - Gottlieb, Eyal A1 - Schulze, Almut T1 - Inhibition of fatty acid desaturation is detrimental to cancer cell survival in metabolically compromised environments JF - Cancer & Metabolism N2 - Background Enhanced macromolecule biosynthesis is integral to growth and proliferation of cancer cells. Lipid biosynthesis has been predicted to be an essential process in cancer cells. However, it is unclear which enzymes within this pathway offer the best selectivity for cancer cells and could be suitable therapeutic targets. Results Using functional genomics, we identified stearoyl-CoA desaturase (SCD), an enzyme that controls synthesis of unsaturated fatty acids, as essential in breast and prostate cancer cells. SCD inhibition altered cellular lipid composition and impeded cell viability in the absence of exogenous lipids. SCD inhibition also altered cardiolipin composition, leading to the release of cytochrome C and induction of apoptosis. Furthermore, SCD was required for the generation of poly-unsaturated lipids in cancer cells grown in spheroid cultures, which resemble those found in tumour tissue. We also found that SCD mRNA and protein expression is elevated in human breast cancers and predicts poor survival in high-grade tumours. Finally, silencing of SCD in prostate orthografts efficiently blocked tumour growth and significantly increased animal survival. Conclusions Our data implicate lipid desaturation as an essential process for cancer cell survival and suggest that targeting SCD could efficiently limit tumour expansion, especially under the metabolically compromised conditions of the tumour microenvironment. KW - SCD KW - lipidomics KW - prostate cancer KW - breast cancer KW - lipid desaturation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145905 VL - 4 IS - 6 ER - TY - JOUR A1 - Haddad, Dana A1 - Chen, Chun-Hao A1 - Carlin, Sean A1 - Silberhumer, Gerd A1 - Chen, Nanhai G. A1 - Zhang, Qian A1 - Longo, Valerie A1 - Carpenter, Susanne G. A1 - Mittra, Arjun A1 - Carson, Joshua A1 - Au, Joyce A1 - Gonen, Mithat A1 - Zanzonico, Pat B. A1 - Szalay, Aladar A. A1 - Fong, Yuman T1 - Imaging Characteristics, Tissue Distribution, and Spread of a Novel Oncolytic Vaccinia Virus Carrying the Human Sodium Iodide Symporter JF - PLoS One N2 - Introduction: Oncolytic viruses show promise for treating cancer. However, to assess therapy and potential toxicity, a noninvasive imaging modality is needed. This study aims to determine the in vivo biodistribution, and imaging and timing characteristics of a vaccinia virus, GLV-1h153, encoding the human sodium iodide symporter (hNIS. Methods: GLV-1h153 was modified from GLV-1h68 to encode the hNIS gene. Timing of cellular uptake of radioiodide \(^{131}\)I in human pancreatic carcinoma cells PANC-1 was assessed using radiouptake assays. Viral biodistribution was determined in nude mice bearing PANC-1 xenografts, and infection in tumors confirmed histologically and optically via Green Fluorescent Protein (GFP) and bioluminescence. Timing characteristics of enhanced radiouptake in xenografts were assessed via \(^{124}\)I-positron emission tomography (PET). Detection of systemic administration of virus was investigated with both \(^{124}\)I-PET and 99m-technecium gamma-scintigraphy. Results: GLV-1h153 successfully facilitated time-dependent intracellular uptake of \(^{131}\)I in PANC-1 cells with a maximum uptake at 24 hours postinfection (P < 0.05). In vivo, biodistribution profiles revealed persistence of virus in tumors 5 weeks postinjection at 10\(^9\) plaque-forming unit (PFU)/gm tissue, with the virus mainly cleared from all other major organs. Tumor infection by GLV-1h153 was confirmed via optical imaging and histology. GLV-1h153 facilitated imaging virus replication in tumors via PET even at 8 hours post radiotracer injection, with a mean % ID/gm of 3.82 \(\pm\) 60.46 (P < 0.05) 2 days after intratumoral administration of virus, confirmed via tissue radiouptake assays. One week post systemic administration, GLV1h153-infected tumors were detected via \(^{124}\)I-PET and 99m-technecium-scintigraphy. Conclusion: GLV-1h153 is a promising oncolytic agent against pancreatic cancer with a promising biosafety profile. GLV-1h153 facilitated time-dependent hNIS-specific radiouptake in pancreatic cancer cells, facilitating detection by PET with both intratumoral and systemic administration. Therefore, GLV-1h153 is a promising candidate for the noninvasive imaging of virotherapy and warrants further study into longterm monitoring of virotherapy and potential radiocombination therapies with this treatment and imaging modality. KW - nude mice KW - pancreatic cancer KW - engineered measles-virus KW - positron-emission-tomography KW - malignant pleural mesothelioma KW - reporter gene KW - replicating adenovirus KW - NA/I symporter KW - breast cancer KW - viral therapy Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130041 VL - 7 IS - 8 ER - TY - JOUR A1 - Harter, Patrick N. A1 - Bernatz, Simon A1 - Scholz, Alexander A1 - Zeiner, Pia S. A1 - Zinke, Jenny A1 - Kiyose, Makoto A1 - Blasel, Stella A1 - Beschorner, Rudi A1 - Senft, Christian A1 - Bender, Benjamin A1 - Ronellenfitsch, Michael W. A1 - Wikman, Harriet A1 - Glatzel, Markus A1 - Meinhardt, Matthias A1 - Juratli, Tareq A. A1 - Steinbach, Joachim P. A1 - Plate, Karl H. A1 - Wischhusen, Jörg A1 - Weide, Benjamin A1 - Mittelbronn, Michel T1 - Distribution and prognostic relevance of tumor-infiltrating lymphocytes (TILs) and PD-1/PD-L1 immune checkpoints in human brain metastases JF - Oncotarget N2 - The activation of immune cells by targeting checkpoint inhibitors showed promising results with increased patient survival in distinct primary cancers. Since only limited data exist for human brain metastases, we aimed at characterizing tumor infiltrating lymphocytes (TILs) and expression of immune checkpoints in the respective tumors. Two brain metastases cohorts, a mixed entity cohort (n = 252) and a breast carcinoma validation cohort (n = 96) were analyzed for CD3+, CD8+, FOXP3+, PD-1+ lymphocytes and PD-L1+ tumor cells by immunohistochemistry. Analyses for association with clinico-epidemiological and neuroradiological parameters such as patient survival or tumor size were performed. TILs infiltrated brain metastases in three different patterns (stromal, peritumoral, diffuse). While carcinomas often show a strong stromal infiltration, TILs in melanomas often diffusely infiltrate the tumors. Highest levels of CD3+ and CD8+ lymphocytes were seen in renal cell carcinomas (RCC) and strongest PD-1 levels on RCCs and melanomas. High amounts of TILs, high ratios of PD-1+/CD8+ cells and high levels of PD-L1 were negatively correlated with brain metastases size, indicating that in smaller brain metastases CD8+ immune response might get blocked. PD-L1 expression strongly correlated with TILs and FOXP3 expression. No significant association of patient survival with TILs was observed, while high levels of PD-L1 showed a strong trend towards better survival in melanoma brain metastases (Log-Rank p = 0.0537). In summary, melanomas and RCCs seem to be the most immunogenic entities. Differences in immunotherapeutic response between tumor entities regarding brain metastases might be attributable to this finding and need further investigation in larger patient cohorts. KW - B7-H1 KW - PD-L1 KW - immunoresistance KW - immunosurveillance KW - safety KW - survival KW - expression KW - melanoma KW - breast cancer KW - PC-1 blockade KW - cell lung cancer KW - tumor-infiltrating lymphocytes KW - brain metastases KW - PD-1 Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137107 VL - 6 IS - 38 SP - 40836 EP - 40849 ER - TY - JOUR A1 - Wang, Huiqiang A1 - Chen, Nanhai G. A1 - Minev, Boris R. A1 - Zimmermann, Martina A1 - Aguilar, Richard J. A1 - Zhang, Qian A1 - Sturm, Julia B. A1 - Fend, Falko A1 - Yu, Yong A. A1 - Cappello, Joseph A1 - Lauer, Ulrich M. A1 - Szalay, Aladar A. T1 - Optical Detection and Virotherapy of Live Metastatic Tumor Cells in Body Fluids with Vaccinia Strains JF - PLoS ONE N2 - Metastatic tumor cells in body fluids are important targets for treatment, and critical surrogate markers for evaluating cancer prognosis and therapeutic response. Here we report, for the first time, that live metastatic tumor cells in blood samples from mice bearing human tumor xenografts and in blood and cerebrospinal fluid samples from patients with cancer were successfully detected using a tumor cell-specific recombinant vaccinia virus (VACV). In contrast to the FDA-approved CellSearch system, VACV detects circulating tumor cells (CTCs) in a cancer biomarker-independent manner, thus, free of any bias related to the use of antibodies, and can be potentially a universal system for detection of live CTCs of any tumor type, not limited to CTCs of epithelial origin. Furthermore, we demonstrate for the first time that VACV was effective in preventing and reducing circulating tumor cells in mice bearing human tumor xenografts. Importantly, a single intra-peritoneal delivery of VACV resulted in a dramatic decline in the number of tumor cells in the ascitic fluid from a patient with gastric cancer. Taken together, these results suggest VACV to be a useful tool for quantitative detection of live tumor cells in liquid biopsies as well as a potentially effective treatment for reducing or eliminating live tumor cells in body fluids of patients with metastatic disease. KW - lymph nodes KW - cancer treatment KW - metastatic tumors KW - breast cancer KW - blood KW - prostate cancer KW - ascites KW - mouse models Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130059 VL - 8 IS - 9 ER - TY - JOUR A1 - Diessner, Joachim A1 - Bruttel, Valentin A1 - Becker, Kathrin A1 - Pawlik, Miriam A1 - Stein, Roland A1 - Häusler, Sebastian A1 - Dietl, Johannes A1 - Wischhusen, Jörg A1 - Hönig, Arnd T1 - Targeting breast cancer stem cells with HER2-specific antibodies and natural killer cells JF - American Journal of Cancer Research N2 - Breast cancer is the most common cancer among women worldwide. Every year, nearly 1.4 million new cases of breast cancer are diagnosed, and about 450.000 women die of the disease. Approximately 15-25% of breast cancer cases exhibit increased quantities of the trans-membrane receptor tyrosine kinase human epidermal growth factor receptor 2 (HER2) on the tumor cell surface. Previous studies showed that blockade of this HER2 proto-oncogene with the antibody trastuzumab substantially improved the overall survival of patients with this aggressive type of breast cancer. Recruitment of natural killer (NK) cells and subsequent induction of antibody-dependent cell-mediated cytotoxicity (ADCC) contributed to this beneficial effect. We hypothesized that antibody binding to HER2-positive breast cancer cells and thus ADCC might be further improved by synergistically applying two different HER2-specific antibodies, trastuzumab and pertuzumab. We found that tumor cell killing via ADCC was increased when the combination of trastuzumab, pertuzumab, and NK cells was applied to HER2-positive breast cancer cells, as compared to the extent of ADCC induced by a single antibody. Furthermore, a subset of \(CD44^{high}CD24^{low}HER2^{low}\) cells, which possessed characteristics of cancer stem cells, could be targeted more efficiently by the combination of two HER2-specific antibodies compared to the efficiency of one antibody. These in vitro results demonstrated the immunotherapeutic benefit achieved by the combined application of trastuzumab and pertuzumab. These findings are consistent with the positive results of the clinical studies, CLEOPATRA and NEOSPHERE, conducted with patients that had HER2-positive breast cancer. Compared to a single antibody treatment, the combined application of trastuzumab and pertuzumab showed a stronger ADCC effect and improved the targeting of breast cancer stem cells. KW - trastuzumab KW - breast cancer KW - tumor stem cells KW - ADCC KW - pertuzumab Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128633 VL - 3 IS - 2 ER -