An immune-competent model of spontaneous breast cancer metastasis to the brain

In breast cancer, brain metastases are often seen as late complications of recurrent disease and represent a particularly serious condition, since there are limited therapeutic options and patients have an unfavorable prognosis. The frequency of brain metastases in breast cancer is currently on the rise. This might be due to the fact that adjuvant chemotherapeutic and targeted anticancer drugs, while they effectively control disease progression in the periphery, they only poorly cross the blood-brain barrier and do not reach effectively cancer cells disseminated in the brain. It is therefore of fundamental clinical relevance to investigate mechanisms involved in breast cancer metastasis to the brain. To date experimental models of breast cancer metastasis to the brain described in literature are based on the direct intracarotid or intracardiac injection of breast cancer cells. We recently established a brain metastasis breast cancer model in immunocompetent mice based on the orthotopic injection of 4T1 murine breast carcinoma cells in the mammary gland of syngeneic BALB/c mice. 4T1-derived tumors recapitulate the main steps of human breast cancer progression, including epithelial-to-mesenchymal transition, local invasion and metastatic spreading to lung and lymph nodes. 4T1 cells were engineered to stably express firefly Luciferase allowing noninvasive in vivo and ex vivo monitoring of tumor progression and metastatic spreading to target organs. Bioluminescence imaging revealed the appearance of spontaneous lesions to the lung and lymph nodes and, at a much lower frequency, to the brain. Brain metastases were confirmed by macroscopic and microscopic evaluation of the brains at necropsy. We then isolated brain metastatic cells, re-injected them orthotopically in new mice and isolated again lines from brain metastases. After two rounds of selection we obtained lines metastasizing to the brain with 100% penetrance (named 4T1-BM2 for Brain Metastasis, 2nd generation) compared to lines derived after two rounds of in vivo growth from primary tumors (4T1-T2) or from lung metastases (4T1-LM2). We are currently performing experiments to unravel differences in cell proliferation, adhesion, migration, invasion and survival of the 4T1-BM2 line relative to the 4T1-T2 and 4T1-LM2 lines. Initial results indicate that 4T1-BM2 cells are not more invasive or more proliferative in vitro and do not show a more mesenchymal phenotype. Our syngeneic (BALB/c) model of spontaneous breast carcinoma metastasis to the brain is a unique and clinically relevant model to unravel the mechanisms of metastatic breast cancer colonization of the brain. Genes identified in this model represent potentially clinically relevant therapeutic targets for the prevention and the treatment of brain metastases in breast cancer patients.

Molecular investigation of lymph nodes in patients with colon cancer: a new road to better staging

Objective: Small nodal tumor infiltrates are identified by applying multilevel sectioning and immunohistochemistry (IHC) in addition to H&E (hematoxylin and eosin) stains of resected lymph nodes. However, the use of multilevel sectioning and IHC is very time-consuming and costly. The current standard analysis of lymph nodes in colon cancer patients is based on one slide per lymph node stained by H&E. A new molecular diagnostic system called ''One tep Nucleic Acid Amplification'' (OSNA) was designed for a more accurate detection of lymph node metastases. The objective of the present investigation was to compare the performance ofOSNAto current standard histology (H&E). We hypothesize that OSNA provides a better staging than the routine use of one slide H&E per lymph node.Methods: From 22 colon cancer patients 307 frozen lymph nodes were used to compare OSNA with H&E. The lymph nodes were cut into halves. One half of the lymph node was analyzed by OSNA. The semi-automated OSNA uses amplification of reverse-transcribed cytokeratin19 (CK19) mRNA directly from the homogenate. The remaining tissue was dedicated to histology, with 5 levels of H&E and IHC staining (CK19).Results: On routine evaluation of oneH&Eslide 7 patients were nodal positive (macro-metastases). All these patients were recognized by OSNA analysis as being positive (sensitivity 100%). Two of the remaining 15 patients had lymph node micro-metastases and 9 isolated tumor cells. For the patients with micrometastases both H&E and OSNA were positive in 1 of the 2 patients. For patients with isolated tumor cells, H&E was positive in 1/9 cases whereas OSNA was positive in 3/9 patients (IHC as a reference). There was only one case to be described as IHC negative/OSNA positive. On the basis of single lymph nodes the sensitivity of OSNA and the 5 levels of H&E and IHC was 94・5%.Conclusion: OSNA is a novel molecular tool for the detection of lymph node metastases in colon cancer patients which provides better staging compared to the current standard evaluation of one slide H&E stain. Since the use of OSNA allows the analysis of the whole lymph node, sampling bias and undetected tumor deposits due to uninvestigated material will be overcome. OSNA improves staging in colon cancer patients and may replace the current standard of H&E staining in the future.

Chirurgie du cancer du sein [Breast cancer surgery].

Breast conserving surgery followed by radiation therapy is the treatment of choice for early breast cancer. For patients who choice or need a mastectomy, breast reconstruction provides an acceptable alternative. Breast cancer surgery has been evolving through minimally invasive approaches. Sentinel node biopsy has already remplaced axillary lymph node dissection in the evaluation of the axilla. Local ablation of the tumor may be a valuable alternative to surgery in the future.

Evaluation de la prise en charge des femmes de plus de 30 ans avec un diagnostic de L-SIL du col de l'utérus en vigueur depuis 2009 au CHUV

Introduction : Les lésions malpighiennes intraépithéliales de bas grade (LSIL) sont un diagnostic rencontré fréquemment lors des frottis de dépistage du cancer du col utérin. Leur prise en charge reste controversée. Au CHUV, avant 2009, un test HPV était effectué chez toutes les femmes avec un diagnostic de L-SIL et seules les patientes avec un test HPV positif pour les hauts risques (HR) étaient adressées en colposcopie. Actuellement, suivant les guidelines européennes de 2006, l'attitude est de faire une colposcopie à toutes les patientes avec un diagnostic initial de L-SIL, sans faire préalablement un test HPV. Cette démarche semble efficiente chez les jeunes patientes, mais pas chez les plus de 30 ans chez qui la prévalence de tests HPV HR positifs est inférieure. Plus de 40% des femmes de plus de 30 ans seraient référées inutilement en colposcopie car elles ne seraient pas infectées par un HPV HR et n'auraient pas de risque d'évolution de leur L-SIL vers une lésion de haut grade. Buts : Comparer les deux différentes prises en charge des femmes de plus de 30 ans présentant un diagnostic de L-SIL, soit celle qui était en vigueur au CHUV avant 2009 et la prise en charge actuelle. Etudier le rôle et l'utilité du test HPV et de la colposcopie dans le suivi de ces femmes. Méthode : Il s'agit d'une étude rétrospective, monocentrique. Nous avons étudié le dossier de toutes les femmes de plus de 30 ans ayant eu une cytologie avec un diagnostic initial de L-SIL du col de l'utérus au CHUV entre le 01.01.09 et le 31.12.10, soit 61 patientes. Résultats : Parmi les 61 femmes inclues dans notre étude 60 ont eu un test HPV effectué lors du diagnostic de L-SIL, dont seuls 29 (48,33%) étaient positifs pour les hauts risques. Comparé aux femmes avec test HPV négatif pour HR, les femmes positives pour HPV HR ont eu un taux inférieur d'évolution spontanément résolutive de leur lésion et un taux supérieur de conisation ou vaporisation du col. Cinq des femmes inclues dans l'étude ont eu une évolution de leurs lésions vers une pathologie plus avancée, dont 4 vers un CIN2 et 1 vers un CIN3. Ces cinq cas étaient positifs pour HPV HR. Conclusion : Les nouvelles guidelines en vigueur au CHUV concernant la prise en charge des femmes avec diagnostic de L-SIL n'étaient pas encore appliquées en 2010, en effet le test HPV a été effectué chez presque la totalité de ces patientes. Ces nouvelles guidelines ne semblent pas être applicables aux femmes de plus de 30 ans, chez qui la prévalence du HPV HR est inférieure, et qui risquent alors de subir des examens complémentaires invasifs, sans qu'il y ait de réel bénéfice sur le pronostic de leur pathologie.

Identification of cancer/testis-antigen genes by massively parallel signature sequencing.

Massively parallel signature sequencing (MPSS) generates millions of short sequence tags corresponding to transcripts from a single RNA preparation. Most MPSS tags can be unambiguously assigned to genes, thereby generating a comprehensive expression profile of the tissue of origin. From the comparison of MPSS data from 32 normal human tissues, we identified 1,056 genes that are predominantly expressed in the testis. Further evaluation by using MPSS tags from cancer cell lines and EST data from a wide variety of tumors identified 202 of these genes as candidates for encoding cancer/testis (CT) antigens. Of these genes, the expression in normal tissues was assessed by RT-PCR in a subset of 166 intron-containing genes, and those with confirmed testis-predominant expression were further evaluated for their expression in 21 cancer cell lines. Thus, 20 CT or CT-like genes were identified, with several exhibiting expression in five or more of the cancer cell lines examined. One of these genes is a member of a CT gene family that we designated as CT45. The CT45 family comprises six highly similar (>98% cDNA identity) genes that are clustered in tandem within a 125-kb region on Xq26.3. CT45 was found to be frequently expressed in both cancer cell lines and lung cancer specimens. Thus, MPSS analysis has resulted in a significant extension of our knowledge of CT antigens, leading to the discovery of a distinctive X-linked CT-antigen gene family.

Successful migration of three tracers without identification of sentinel nodes during intraoperative lymphatic mapping for non-small cell lung cancer.

Prospective comparative evaluation of patent V blue, fluorescein and (99m)TC-nanocolloids for intraoperative sentinel lymph node (SLN) mapping during surgery for non-small cell lung cancer (NSCLC). Ten patients with peripherally localised clinical stage I NSCLC underwent thoracotomy and peritumoral subpleural injection of 2 ml of patent V blue dye, 1 ml of 10% fluorescein and 1ml of (99m)Tc-nanocolloids (0.4 mCi). The migration and spatial distribution pattern of the tracers was assessed by direct visualisation (patent V blue), visualisation of fluorescence signalling by a lamp of Wood (fluorescein) and radioactivity counting with a hand held gamma-probe ((99m)Tc-nanocolloids). Lymph nodes at interlobar (ATS 11), hilar (ATS 10) and mediastinal (right ATS 2,4,7; left ATS 5,6,7) levels were systematically assessed every 10 min up to 60 min after injection, followed by lobectomy and formal lymph node dissection. Successful migration from the peritumoral area to the mediastinum was observed for all three tracers up to 60 min after injection. The interlobar lympho-fatty tissue (station ATS 11) revealed an early and preferential accumulation of all three tracers for all tumours assessed and irrespective of the tumour localisation. However, no preferential accumulation in one or two distinct lymph nodes was observed up to 60 min after injection for all three tracers assessed. Intraoperative SLN mapping revealed successful migration of the tracers from the site of peritumoral injection to the mediastinum, but in a diffuse pattern without preferential accumulation in sentinel lymph nodes.

Prostate cancer: F-18-fluorocholine PET-CT utility. [Cancer de la prostate : utilité de la TEP-TDM à la 18F-fluorocholine.]

In oncology, positron emission computed tomography (PET/CT) has become an essential tool for initial staging, response evaluation and follow-up of cancer patients. Most of the frequent tumors (lung, breast, esophagus, and lymphomas) are highly avid for (18)F-fluorodeoxyglucose ((18)FDG), but prostate cancer has not demonstrated significant uptake of FDG. The development of new tracers labeled with (18)F such as choline analogs allowed already to obtain interesting results particularly in patients with biological relapse and inconclusive conventional imaging workup. The impact of (18)F-flurocholine PET/CT on patient management needs to be validated in large studies, but many centers use already this examination in order to guide further management, including radiotherapy planning. (C) 2011 Elsevier Masson SAS. All rights reserved.

Treatment of brain metastases from non-small cell lung cancer with whole-brain radiotherapy (wbrt) in combination with gefitinib (gft) or temozolomide (tmz): a randomized multicenter phase ii trial of the swiss group of clinical cancer research (sakk #70/03)

BACKGROUND: Patients with BM rarely survive .6 months and are commonly excluded from clinical trials. We aimed at improving outcome by exploring 2 combined modality regimens with at the time novel agents for which single-agent activity had been shown. METHODS: NSCLC patients with multiple BM were randomized to WBRT (10 × 3 Gy) and either GFT 250 mg p.o. daily or TMZ 75 mg/m2 p.o. daily ×21/28 days, starting on Day 1 of RT and to be continued until PD. Primary endpoint was overall survival, a Simon's optimal 2-stage design was based on assumptions for the 3-month survival rate. Cognitive functioning and quality of life were also evaluated. RESULTS: Fifty-nine patients (36 M, 23 F; 9 after prior chemo) were included. Median age was 61 years (range 46-82), WHO PS was 0 in 18 patients, 1 in 31 patients, and 2 in 10 patients. All but 1 patients had extracranial disease; 33 of 43 (TMZ) and 15 of 16 (GFT) had adenocarcinoma histology. GFT arm was closed early after stage 1 analysis when the prespecified 3-mo survival rate threshold (66%) was not reached, causes of death were not GFT related. Main causes of death were PD in the CNS 24%, systemic 41%, both 8%, and toxicity 10% [intestinal perforation (2 patients), pneumonia (2), pulmonary emboli (1), pneumonitis NOS (1), seizure (1)]. We summarize here other patients' characteristics for the 2 trial arms: TMZ (n ¼ 43)/GFT (n ¼ 16); median treatment duration: 1.6 /1.8 mo; Grade 3-4 toxicity: lymphopenia 5 patients (12%)/0; fatigue 8 patients (19%)/2 patients (13%). Survival data for TMZ/GFT arms: 3-month survival rate: 58.1% (95% CI 42.1-73)/62.5% (95% CI 35- 85); median OS: 4.9 months (95% CI 2.5-5.6)/6.3 months (95% CI 2.2- 14.6); median PFS: 1.8 months (95% CI 1.5-1.8)/1.8 (95% CI 1.1-3.9); median time to neurol. progr.: 8.0 months (95% CI 2.2-X)/4.8 (95% CI 3.9-10.5). In a model to predict survival time including the variables' age, PS, number of BM, global QL, total MMSE score, and subjective cognitive function, none of the variables accounted for a significant improvement in survival time. CONCLUSIONS: The combinations of WBRT with GFT or TMZ were feasible. However, in this unselected patient population, survival remains poor and a high rate of complication was observed. Four patients died as a result of high-dose corticosteroids. Preliminary evaluation of cognitive function andQL failed to show significant improvement. Indications and patient selection for palliative treatment should be revisited and careful monitoring and supportive care is required. Research and progress for this frequent clinical situation is urgently needed. Trial partly supported by AstraZeneca (Switzerland), Essex Chemie (Switzerland) and Swiss Federal Government.

Consolidation whole abdomen irradiation following adjuvant carboplatin-paclitaxel based chemotherapy for advanced uterine epithelial cancer: feasibility, toxicity and outcomes.

BACKGROUND: To evaluate feasibility and preliminary outcomes associated with sequential whole abdomen irradiation (WAI) as consolidative treatment following comprehensive surgery and systemic chemotherapy for advanced endometrial cancer. METHODS: We conducted a retrospective analysis of patients treated at our institution from 2000 to 2011. Inclusion criteria were stage III-IV endometrial cancer patients with histological proof of one or more sites of extra-uterine abdomen-confined disease, treated with WAI as part of multimodal therapy. Endpoints were feasibility, acute toxicity, late effects, recurrence-free survival (RFS) and overall survival (OS). Twenty patients were identified. Chemotherapy consisted of 3 to 6 cycles of a platinum-paclitaxel regimen in 18 patients. WAI was delivered using conventional technique to a median total dose of 27.5 Gy. RESULTS: No grade 4 toxicities occurred during chemotherapy or radiotherapy. No radiation dose reduction was necessary. Three patients developed small bowel obstruction, all in the context of recurrent intraperitoneal disease. Kaplan-Meier estimates and 95% confidence intervals for RFS and OS at one year were 63% (38-80%) and 83% (56-94%) and at 3 years 57% (33-76%) and 62% (34-81%), respectively. On univariate Cox analysis, stage IVB and serous papillary (SP) histology were found to be statistically significantly (at the p = 0.05 level) associated with worse RFS and OS. The peritoneal cavity was the most frequent site of initial failure. CONCLUSIONS: Consolidative WAI following chemotherapy is feasible and can be performed without interruption with manageable acute and late toxicity. Patients with endometrioid adenocarcinoma, especially stage FIGO III, had favorable outcomes possibly meriting prospective evaluation of the addition of WAI following chemotherapy in selected patients. Patients with SP do poorly and do not routinely benefit from this approach.

The potential of metastatic lymph nodes to predict positive resection margins in patients with resectable pancreatic cancer

Objective: Despite progress during recent decades, long-term outcome¦of patients with pancreatic cancer remains dismal. Since positive resection¦margins and metastatic lymph nodes are known risk factors for early tumor¦recurrence, patients at risk should be identified and could potentially benefit¦from preoperative radio-chemotherapy. This study aimed to assess whether the¦presence of lymph node metastasis could be used to predict positive resection¦margins in patients with pancreatic cancer.¦Methods: A series of 146 patients (82 male, 64 female, median age 68 years)¦underwent pancreatic head resection for various malignant diseases (pancreatic¦ductal adenocarcinoma, biliary cancer, periampullary cancer) at our institution¦from 2000 to 2011. Patients were identified from our prospective database¦that collects more than 60 single items of all patients undergoing pancreatic¦resection. Lymph node metastasis and positive resection margins were all¦confirmed by histological evaluation. Positive predictive value (PPV), negative¦predictive value (NPV), sensitivity and specificity were calculated to assess¦the predictive value of metastatic lymph nodes regarding tumor-free (R0) and¦tumor-involved (R1) resection margins.¦Results: There were 110 specimens (76%) with tumor-positive lymph nodes¦and 36 specimens with tumor-negative lymph nodes. Resection margins were¦positive in 47 specimens (32%) and negative in 99 specimens. Sensitivity of¦tumor-positive lymph nodes to detect positive resection margins was 96%, and¦the NPV was 94%. In contrast, specificity was 34% and the PPV was 41%.¦Conclusion: Patients with resectable pancreatic cancer, who have no lymph¦node metastasis, are at very low risk to have positive resection margins (2 of¦36 patients, NPV 94%). In contrast, more than one third of patients with¦metastatic lymph nodes are at increased risk for an incomplete tumor resection¦(sensitivity 96%). If lymph nodesmetastases are highly suspected at preoperative¦staging, a neoadjuvant treatment strategy should be considered to increase the¦R0 resection rate.

Compliance with preoperative oral nutritional supplements in patients at nutritional risk─only a question of will?

BACKGROUND/OBJECTIVES: Preoperative nutrition has been shown to reduce morbidity after major gastrointestinal (GI) surgery in selected patients at risk. In a randomized trial performed recently (NCT00512213), almost half of the patients, however, did not consume the recommended dose of nutritional intervention. The present study aimed to identify the risk factors for noncompliance. SUBJECTS/METHODS: Demographic (n=5) and nutritional (n=21) parameters for this retrospective analysis were obtained from a prospectively maintained database. The outcome of interest was compliance with the allocated intervention (ingestion of ⩾11/15 preoperative oral nutritional supplement units). Uni- and multivariate analyses of potential risk factors for noncompliance were performed. RESULTS: The final analysis included 141 patients with complete data sets for the purpose of the study. Fifty-nine patients (42%) were considered noncompliant. Univariate analysis identified low C-reactive protein levels (P=0.015), decreased recent food intake (P=0.032) and, as a trend, low hemoglobin (P=0.065) and low pre-albumin (P=0.056) levels as risk factors for decreased compliance. However, none of them was retained as an independent risk factor after multivariate analysis. Interestingly, 17 potential explanatory parameters, such as upper GI cancer, weight loss, reduced appetite or co-morbidities, did not show any significant correlation with reduced intake of nutritional supplements. CONCLUSIONS: Reduced compliance with preoperative nutritional interventions remains a major issue because the expected benefit depends on the actual intake. Seemingly, obvious reasons could not be retained as valid explanations. Compliance seems thus to be primarily a question of will and information; the importance of nutritional supplementation needs to be emphasized by specific patients' education.

Systematic evaluation of clinical predictors of aggressive ulcerative colitis

Background: Studies evaluating risk factors associated with an "aggressive" disease course in ulcerative colitis (UC) are scarce. A recent definition of "aggressive" UC incorporated the following characteristics: 1) high relapse rate, 2) need for surgery, 3) development of colorectal cancer, and 4) presence of extraintestinal manifestations (EIM). The following factors for an aggressive / disabling disease course in UC have been identified so far: age < 40 years at S140 Poster presentations UC diagnosis, pancolitis, concomitant primary sclerosing cholangitis, and deep ulcerations of the colonic mucosa. We aimed to evaluate risk factors for an "aggressive" disease course in UC patients. Methods: Data from the Swiss IBD cohort study were analyzed. Patients were recruited from university centers (80%), regional hospitals (19%), and private practices (1%). We applied the following definition for "aggressive" UC: 1) patients ever treated with TNFantagonists or calcineurin inhibitors (tacrolimus / cyclosporine), and 2) need for (procto)-colectomy. Non-normal data are presented as median and interquartile range [IQR].

Dépistage du cancer ovarien dans la population générale [Ovarian cancer screening in the general population].

Although the incidence of ovarian cancer is low, mortality from this cancer is high due to discovery at a late stage in the majority of cases. So it seems worthwhile to detect ovarian cancer at an early stage. The clinical presentation is nonspecific, thus screening tools have been evaluated. The most efficient screening technique includes two steps: evaluation of CA-125 and then sonography in case of abnormal results of CA-125. Two main studies have been performed in large populations. The PLCO-study has led to negative results: no reduction in ovarian cancer mortality in the screening group with an important increase in surgical morbidity. The final results of the UKCTOCS-study will be known in two years. Currently these data can't allow the realization of ovarian cancer screening in the general population, mainly due to their natural history.

Ewing sarcoma cancer stem cells : from mechanisms to therapeutic targeting

Le sarcome d'Ewing (SE) est la 2ème tumeur des os la plus fréquente chez les enfants, et le pronostic est sombre au stade métastatique. La pathogenèse du SE repose sur une translocation, provocant la fusion du domaine activateur du facteur de transcription EWS, avec la partie liant l'ADN de la protéine FLI-1. Les cellules souches cancéreuses (CSC) sont supposées être les moteurs de la croissance tumorale, et représente de ce fait des cibles thérapeutiques préférentielles. Dans ce travail nous nous sommes efforcés de comprendre, ainsi que de cibler les mécanismes liés à l'émergence des CSC dans le sarcome d'Ewing. La formation des CSC du ES est liée à un défaut de maturation des miRNAs provoqué par une sous-expression d'un gène, TARBP2, dans les CSC. Ce défaut de maturation peut être corrigé par un traitement des cellules avec de l'enoxacine, une fluoroquinolone utilisée pour traiter les infections urinaires. L'enoxacine seule n'étant pas suffisante pour éradiquer les tumeurs in vivo, nous avons testé la combinaison d'une thérapie ciblée sur les CSC avec une chimiothérapie classique, la doxorubicine, ciblant les cellules différentiées. In vitro l'enoxacine induit l'apoptose dans les CCS sans affecter les cellules différentiées, alors que à l'inverse, la doxorubicine n'affecte que les cellules de la « masse » tumorale. In vivo la combinaison de ces deux drogues inhibe la croissance de tumeurs provenant de cellules primaires xenotranplantées et éradique les CSCs. Nos résultats mettent en lumière une nouvelle approche thérapeutique directement applicable pour le sarcome d'Ewing, et pourraient ainsi rapidement déboucher sur des essais cliniques. Dans la deuxième partie de ce travail nous avons essayé de comprendre comment EWS-FLI1, la protéine de fusion issue de la translocation chromosomique du sarcome d'Ewing conduit à la génération des CSC. Pour cela nous avons effectué des ChIPseq (immunoprecipitation de la chromatine suivi de séquençage) pour EWS-FLI1 ainsi que pour certaines modifications histoniques. -- Ewing sarcoma family tumors (ESFT) are the second most frequent bone tumors in children and have a high rate of recurrence when metastatic at presentation. The pathogenesis of Ewing sarcoma is underlayed by a translocation, leading to the fusion of the trans-activating domain of EWS with the FLU DNA binding domain. Cancer stem cells (CSCs) are thought to be the driving force of tumor growth. In this work we focused on understanding the mechanisms underlying ESFT CSC emergence as well as defining targeted therapeutic strategies. Emergence of CSCs in ESFT has been shown to arise from a defect in TARBP2-dependent microRNA maturation, which can be corrected by exposure to the fluoroquinolone enoxacin. As enoxacin alone is not sufficient to reverse tumor growth in vivo, we assessed the effect of combining a drug that abrogates CSC properties with doxorubicin, a standard-of-care therapy in ESFT. Primary ESFT CSCs and bulk tumor cells were treated with different concentration of drugs and displayed divergent responses to doxorubicin and enoxacin. Doxorubicin, which targets the tumor bulk, displayed toxicity toward primary adherent ESFT cells in culture but not to CSC-enriched ESFT spheres. Conversely, enoxacin induced apoptosis but only in ESFT spheres and specifically on the CD133+ population. In combination, the two drugs markedly depleted CSC and strongly reduced primary growth in xenograft assays of two primary ESFT. Our results identify a potentially attractive therapeutic strategy for ESFT that combines mechanism-based targeting of CSC using a low toxicity antibiotic with a standard-of-care cytotoxic drug, offering immediate applications for clinical evaluation. In the second part of this work we performed chromatin immunopercipitation on CSCs and bulk cells for EWS-FLI1 binding as well as some chromatin modifications, and concluded that EWS-FLI1 shows cell context dependent binding.