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Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor with high susceptibility to metastasize. The underlying molecular mechanisms leading to EWS metastases remain poorly understood. Epigenetic changes have been implicated in EWS tumor growth and progression. Linking epigenetics and metastases may provide insight into novel molecular targets in EWS and improve its treatment. Here, we evaluated the effects of a selective G9a histone methyltransferase inhibitor (BIX01294) on EWS metastatic process. Our results showed that overexpression of G9a in tumors from EWS patients correlates with poor prognosis. Moreover, we observe a significantly higher expression of G9a in metastatic EWS tumor as compared to either primary or recurrent tumor. Using functional assays, we demonstrate that pharmacological G9a inhibition using BIX01294 disrupts several metastatic steps in vitro, such as migration, invasion, adhesion, colony formation and vasculogenic mimicry. Moreover, BIX01294 reduces tumor growth and metastases in two spontaneous metastases mouse models. We further identified the sialidase NEU1 as a direct target and effector of G9a in the metastatic process in EWS. NEU1 overexpression impairs migration, invasion and clonogenic capacity of EWS cell lines. Overall, G9a inhibition impairs metastases in vitro and in vivo through the overexpression of NEU1. G9a has strong potential as a prognostic marker and may be a promising therapeutic target for EWS patients., Research in the EDA and OMT labs are supported by “Asociación Española Contra el Cáncer” (AECC). EDA lab is also supported by the Ministry of Economy and Competitiveness of Spain-FEDER (CIBERONC, PI2000003, RD06/0020/0059). DGD and LHP are supported by CIBERONC (CB16/12/00361)S. LHP is funded by the Consejería de Salud de la Junta de Andalucía (PI-0013-2018). SRV is supported by “Asociación Alba Pérez lucha contra el cáncer infantil”. The OMT lab is supported by the Catalan Agency for the Management of University and Research Grants (AGAUR 2017 SGR 332).

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein overexpressed by several cancers. Because SPARC shows high binding affinity to albumin, we reasoned that pediatric sarcoma xenografts expressing SPARC would show enhanced uptake and accumulation of nanoparticle albumin-bound (nab)-paclitaxel, a potent anticancer drug formulation. We first evaluated the expression of SPARC in patient-derived xenografts (PDXs) of Ewing sarcoma, rhabdomyosarcoma and osteosarcoma, finding variable SPARC gene expression that correlated well with SPARC protein measured by immunoblotting. We revealed that the activity of the fusion gene chimera EWSR1-FLI1, the genetic driver of Ewing sarcoma, leads to lower expression of the gene SPARC in these tumors, likely due to enriched acetylation marks of the histone H3 lysine 27 at regions including the SPARC promoter and potential enhancers. Then, we used SPARC-edited Ewing sarcoma cells (A673 line) to demonstrate that SPARC knocked down (KD) cells accumulated significantly less amount of nab-paclitaxel in vitro than SPARC wild type (WT) cells. In vivo, SPARC KD and SPARC WT subcutaneous xenografts in mice achieved similar maximum intratumoral concentrations of nab-paclitaxel, though drug clearance from SPARC WT tumors was significantly slower. We confirmed such SPARC-mediated long-term intratumoral accumulation of nab-paclitaxel in Ewing sarcoma PDX with high expression of SPARC, which accumulated significantly more nab-paclitaxel than SPARC-low PDX. SPARC-high PDX responded better to nab-paclitaxel than SPARC-low tumors, although these results should be taken cautiously, given that the PDXs were established from different patients that could have specific determinants predisposing response to paclitaxel. In addition, SPARC KD Ewing sarcoma xenografts responded better to soluble docetaxel and paclitaxel than to nab-paclitaxel, while SPARC WT ones showed similar response to soluble and albumin-carried drugs. Overall, our results show that pediatric sarcomas expressing SPARC accumulate nab-paclitaxel for longer periods of time, which could have clinical implications for chemotherapy efficacy., AMC acknowledges funding from AECC Scientific Foundation, MINECO (SAF2011-22660), European Union Seventh Framework Programme (FP7/2007-2013) under Marie Curie International Reintegration Grant (PIRG-08-GA-2010-276998) and ISCIII-FEDER (CP13/00189 and CPII18/00009). EDA, OMT and JM acknowledge support of AECC Scientific Foundation (GCB13131578). NU acknowledges funding by the Basque Government, Research Groups of the Basque University System (Project No. IT 1186-19). We thank support of the Central Service of Analysis in Alava, SGIker (UPV/EHU/ERDF, EU) and Xarxa de Bancs de Tumors de Catalunya (XBTC) sponsored by Pla Director d'Oncologia de Catalunya.

Purpose:Endoglin (ENG; CD105) is a coreceptor of the TGFβ family that is highly expressed in proliferating endothelial cells. Often coopted by cancer cells, ENG can lead to neo-angiogenesis and vasculogenic mimicry in aggressive malignancies. It exists both as a transmembrane cell surface protein, where it primarily interacts with TGFβ, and as a soluble matricellular protein (sENG) when cleaved by matrix metalloproteinase 14 (MMP14). High ENG expression has been associated with poor prognosis in Ewing sarcoma, an aggressive bone cancer that primarily occurs in adolescents and young adults. However, the therapeutic value of ENG targeting has not been fully explored in this disease.Experimental Design:We characterized the expression pattern of transmembrane ENG, sENG, and MMP14 in preclinical and clinical samples. Subsequently, the antineoplastic potential of two novel ENG-targeting monoclonal antibody–drug conjugates (ADC), OMTX503 and OMTX703, which differed only by their drug payload (nigrin-b A chain and cytolysin, respectively), was assessed in cell lines and preclinical animal models of Ewing sarcoma.Results:Both ADCs suppressed cell proliferation in proportion to the endogenous levels of ENG observed in vitro. Moreover, the ADCs significantly delayed tumor growth in Ewing sarcoma cell line–derived xenografts and patient-derived xenografts in a dose-dependent manner.Conclusions:Taken together, these studies demonstrate potent preclinical activity of first-in-class anti-ENG ADCs as a nascent strategy to eradicate Ewing sarcoma.

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PURPOSE The aim of this study was to assess the cost-effectiveness of using next-generation sequencing (NGS) versus single-gene testing (SgT) for the detection of genetic molecular subtypes and oncogenic markers in patients with advanced non–small-cell lung cancer (NSCLC) in the setting of Spanish reference centers. METHODS A joint model combining decision tree with partitioned survival models was developed. A two-round consensus panel was performed to describe clinical practice of Spanish reference centers, providing data on testing rate, prevalence of alterations, turnaround times, and treatment pathways. Treatment efficacy data and utility values were obtained from the literature. Only direct costs (euros, 2022), obtained from Spanish databases, were included. A lifetime horizon was considered, so a 3% discount rate for future costs and outcomes was considered. Both deterministic and probabilistic sensitivity analyses were performed to assess uncertainty. RESULTS A target population of 9,734 patients with advanced NSCLC was estimated. If NGS was used instead of SgT, 1,873 more alterations would be detected and 82 more patients could potentially be enrolled in clinical trials. In the long term, using NGS would provide 1,188 additional quality-adjusted life-years (QALYs) in the target population compared with SgT. On the other hand, the incremental cost of NGS versus SgT in the target population was €21,048,580 euros for a lifetime horizon (€1,333,288 for diagnosis phase only). The obtained incremental cost-utility ratios were €25,895 per QALY gained, below the standard cost-effectiveness thresholds. CONCLUSION Using NGS in Spanish reference centers for the molecular diagnosis of patients with metastatic NSCLC would be a cost-effective strategy over SgT.

The recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionized the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children and are either rare tumours with common NTRK fusions that may be diagnostic, or more common tumours with rare NTRK fusions. To assess the currently available evidence, 3key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathology (SEAP) and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical and therapeutic aspects of NTRK-fusion tumours. It also discusses the challenges related to the routine detection of these genetic alterations in a mostly public health care system.

Endoglin (ENG) is a mesenchymal stem cell (MSC) marker typically expressed by active endothelium. This transmembrane glycoprotein is shed by matrix metalloproteinase 14 (MMP14). Our previous work demonstrated potent preclinical activity of first-in-class anti-ENG antibody-drug conjugates as a nascent strategy to eradicate Ewing sarcoma (ES), a devastating rare bone/soft tissue cancer with a putative MSC origin. We also defined a correlation between ENG and MMP14 expression in ES. Herein, we show that ENG expression is significantly associated with a dismal prognosis in a large cohort of ES patients. Moreover, both ENG/MMP14 are frequently expressed in primary ES tumors and metastasis. To deepen in their functional relevance in ES, we conducted transcriptomic and proteomic profiling of in vitro ES models that unveiled a key role of ENG and MMP14 in cell mechano-transduction. Migration and adhesion assays confirmed that loss of ENG disrupts actin filament assembly and filopodia formation, with a concomitant effect on cell spreading. Furthermore, we observed that ENG regulates cell-matrix interaction through activation of focal adhesion signaling and protein kinase C expression. In turn, loss of MMP14 contributed to a more adhesive phenotype of ES cells by modulating the transcriptional extracellular matrix dynamics. Overall, these results suggest that ENG and MMP14 exert a significant role in mediating correct spreading machinery of ES cells, impacting the aggressiveness of the disease., E.A.’s laboratory is supported by ISCIII-FEDER (PI20/00003), CIBERONC (CB16/12/00361), PAIDI-Junta de Andalucía (P18-RT-735), Fundación CRIS Contra el Cáncer, Asociación Candela Riera and Asociación Pablo Ugarte. A.T.A. is supported by Juan de la Cierva Incorporación fellowship (IJC-2018-036767-I); P.P.-C. is sponsored by the Fundación María García Estrada. J.O.-P is supported by Ph.D. Grant Plan Propio from the University of Seville. J.D.-M is supported by CIBERONC (CB16/12/00361). C.S.-A. is supported by the European Social Fund and the Junta de Andalucía (Talento Doctores 2020, DOC_01473). This work was supported by grants from the Consejería de Salud (Junta de Andalucía, grants No PI-0036-2017, PI-0040-2017, and PI-0061-2020) awarded to J.D.-M, A.T.A. and C. S.-A., respectively. This work was also supported by the GEIS-Fundación Mari Paz Jiménez Casado (IV beca trienal) granted to J.D.-M, the 13ª GEIS-Beca Buesa granted to A.T.A. and CRIS (Cancer Research Innovation Spain) granted to J.D.-M and E.A. The laboratory of T.G.P.G. is supported by the Barbara and Wilfried Mohr Foundation. The lab of J.A. is supported by the Instituto de Salud Carlos III (ISCIII), grant number PI20CIII/00020; Asociación Pablo Ugarte, grant numbers TRPV205/18, TPI-M 1149/13; Asociación Candela Riera; Asociación Todos Somos Iván & Fundación Sonrisa de Alex, grant reference: TVP333-19.

Tumor growth depends on the vascular system, either through the expansion of blood vessels or novel adaptation by tumor cells. One of these novel pathways is vasculogenic mimicry (VM), which is defined as a tumor-provided vascular system apart from endothelial cell-lined vessels, and its origin is partly unknown. It involves highly aggressive tumor cells expressing endothelial cell markers that line the tumor irrigation. VM has been correlated with high tumor grade, cancer cell invasion, cancer cell metastasis, and reduced survival of cancer patients. In this review, we summarize the most relevant studies in the field of angiogenesis and cover the various aspects and functionality of aberrant angiogenesis by tumor cells. We also discuss the intracellular signaling mechanisms involved in the abnormal presence of VE-cadherin (CDH5) and its role in VM formation. Finally, we present the implications for the paradigm of tumor angiogenesis and how targeted therapy and individualized studies can be applied in scientific analysis and clinical settings.

[ES] Los pacientes con cáncer y alteraciones oncogénicas potencialmente tratables están aumentando de forma considerable. El diagnóstico de estas alteraciones permite frecuentemente realizar un tratamiento personalizado inicial o a la progresión, así como conocer información predictiva sobre la eficacia de la inmunoterapia. Sin embargo, en un 25% de los casos, la biopsia de tejido inicial no es informativa o no es posible realizar el perfil genómico tumoral a la progresión por la dificultad para obtener nuevas biopsias de tejido tumoral. Por ello, son necesarias alternativas diagnósticas eficaces para la estratificación molecular, que permitan una valoración dinámica del perfil genómico tumoral, como la biopsia líquida, reflejando además la heterogeneidad genómica en el seno del mismo paciente. Actualmente, existen distintas técnicas diagnósticas de biopsia líquida, cada una con distintos grados de precisión y rendimiento. El objetivo de este consenso de la Sociedad Española de Anatomía Patológica (SEAP) y la Sociedad Española de Oncología Médica (SEOM) es evaluar la viabilidad y efectividad de las distintas técnicas de biopsia líquida en el paciente con cáncer en la práctica clínica diaria. Los expertos de este consenso concluyen que la biopsia líquida es una alternativa aceptable a la biopsia de tejido para el estudio de biomarcadores. Sin embargo, es importante estandarizar los procedimientos preanalíticos y analíticos, garantizar su reproducibilidad, así como generar informes clínicos estructurados y comprensibles. La implementación de comités multidisciplinares de evaluación de las alteraciones moleculares es fundamental para mejorar estos procesos y favorecer las decisiones terapéuticas más adecuadas para cada paciente con cáncer en función de perfil genómico., [EN] The proportion of cancer patients with tumours that harbour a potentially targetable genomic alteration is increasing considerably. The diagnosis of these genomic alterations can lead to tailoring of treatment, at the onset of disease or during progression, as well as providing additional, predictive information on the efficacy of immunotherapy. However, in up to 25% of cases, the initial tissue biopsy is inadequate for precision oncology and, in many cases, tumour genomic profiling at progression is not possible due to technical limitations of obtaining new tumour tissue specimens. Efficient diagnostic alternatives are therefore required for molecular stratification, such as liquid biopsy. This technique enables the evaluation of the tumour genomic profile dynamically and as well as capturing intra-patient genomic heterogeneity. To date, there are several diagnostic techniques available for use in liquid biopsy, each with different precision and performance levels. The objective of this consensus statement of the Spanish Society of Pathology (SEAP) and the Spanish Society of Medical Oncology (SEOM) is to evaluate the viability and effectiveness of the different methodological approaches of liquid biopsy in cancer patients, and the potential application of this method to current clinical practice. The experts contributing to this consensus statement agree that, according to current evidence, liquid biopsy is an acceptable alternative to tumour tissue biopsy for the study of biomarkers in various clinical settings. It is therefore important to standardise pre-analytical and analytical procedures to ensure reproducibility and to generate structured and accessible clinical reports. It is essential to appoint multidisciplinary tumour molecular committees to oversee these processes and to enable the most suitable therapeutic decisions for each patient according to the genomic profile.

The majority of current cancer therapies are aimed at reducing tumour growth, but there is lack of viable pharmacological options to reduce the formation of metastasis. This is a paradox, since more than 90% of cancer deaths are attributable to metastatic progression. Integrin alpha9 (ITGA9) has been previously described as playing an essential role in metastasis; however, little is known about the mechanism that links this protein to this process, being one of the less studied integrins. We have now deciphered the importance of ITGA9 in metastasis and provide evidence demonstrating its essentiality for metastatic dissemination in rhabdomyosarcoma and neuroblastoma. However, the most translational advance of this study is to reveal, for the first time, the possibility of reducing metastasis by pharmacological inhibition of ITGA9 with a synthetic peptide simulating a key interaction domain of ADAM proteins, in experimental metastasis models, not only in childhood cancers but also in a breast cancer model., This research was supported by grants from: Institut Català d’Oncologia (ICO); Instituto de Salud Carlos III (PI18/00398 and FI18/00178); ACCIÓ (COMRDI15-1-0014); Fundació la Marató de TV3; Fundació A. BOSCH; Rotary Clubs Barcelona Eixample, Barcelona Diagonal, Santa Coloma de Gramanet, München-Blutenburg, Deutschland Gemeindienst e.V. and others from Barcelona and province; Eric Abidal Foundation; Del Hospital a la catedral Initiative by Xavi Vallès; and Mi compañero de viaje Association.

Vasculogenic Mimicry (VM) refers to the capacity to form a blood network from aggressive cancer cells in an independent way of endothelial cells, to provide nutrients and oxygen leading to enhanced microenvironment complexity and treatment failure. In a previous study, we demonstrated that VE-Cadherin and its phosphorylation at Y658 modulated kaiso-dependent gene expression (CCND1 and Wnt 11) through a pathway involving Focal Adhesion kinase (FAK). In the present research, using a proteomic approach, we have found that β-catenin/TCF-4 is associated with nuclear VE-cadherin and enhances the capacity of malignant melanoma cells to undergo VM in cooperation with VE-Cadherin; in addition, preventing the phosphorylation of Y658 of VE-cadherin upon FAK disabling resulted in VE-Cadherin/β-catenin complex dissociation, increased β-catenin degradation while reducing TCF-4-dependent genes transcription (C-Myc and Twist-1). Uveal melanoma cells knockout for VE-Cadherin loses β-catenin expression while the rescue of VE-Cadherin (but not of the phosphorylation defective VE-Cadherin Y658F mutant) permits stabilization of β-catenin and tumor growth reduction in vivo experiments. In vivo, the concomitant treatment with the FAK inhibitor PF-271 and the anti-angiogenic agent bevacizumab leads to a strong reduction in tumor growth concerning the single treatment. In conclusion, the anomalous expression of VE-Cadherin in metastatic melanoma cells (from both uveal and cutaneous origins), together with its permanent phosphorylation at Y658, favors the induction of the aggressive VM phenotype through the cooperation of β-catenin with VE-Cadherin and by enhancing TCF-4 genes-dependent transcription.

The Hippo pathway is an evolutionarily conserved modulator of developmental biology with a key role in tissue and organ size regulation under homeostatic conditions. Like other signaling pathways with a significant role in embryonic development, the deregulation of Hippo signaling contributes to oncogenesis. Central to the Hippo pathway is a conserved cascade of adaptor proteins and inhibitory kinases that converge and regulate the activity of the oncoproteins YAP and TAZ, the final transducers of the pathway. Elevated levels and aberrant activation of YAP and TAZ have been described in many cancers. Though most of the studies describe their pervasive activation in epithelial neoplasms, there is increasing evidence pointing out its relevance in mesenchymal malignancies as well. Interestingly, somatic or germline mutations in genes of the Hippo pathway are scarce compared to other signaling pathways that are frequently disrupted in cancer. However, in the case of sarcomas, several examples of genetic alteration of Hippo members, including gene fusions, have been described during the last few years. Here, we review the current knowledge of Hippo pathway implication in sarcoma, describing mechanistic hints recently reported in specific histological entities and how these alterations represent an opportunity for targeted therapy in this heterogeneous group of neoplasm., E.d.Á.’s laboratory is supported by ISCIIIFEDER (PI20/00003) to E.d.Á., Consejería de Salud y Familias, Junta de Andalucía (PE-0186-2018) to E.d.Á. and (PI-0061-2020) to C.S.-A. and E.d.Á., GEIS (Beca José María Buesa) to A.T.A., GEIS-Fundación Mari Paz Jiménez Casado (Beca Trienal a la Investigación en Sarcomas) to J.D.-M., Fundación CRIS Contra el Cáncer, Asociación Pablo Ugarte, Fundación María García Estrada and CIBERONC. C.S.-A. is supported by the European Social Fund and the Junta de Andalucía (Talento Doctores 2020, DOC_01473), J.O.-P. is granted by a pre-doctoral fellowship from the VI Plan Propio from the Universidad de Sevilla; A.T.A. is supported Juan de la Cierva Incorporación fellowship (IJC-2018-036767-I), and J.D.-M. is supported by CIBERONC (CB16/12/00361).

This article belongs to the Special Issue Diagnosis and Treatment for Bone Tumor and Sarcoma., [Simple Summary] A solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that can arise at any body location. Local or distant recurrences occur in a significant proportion of cases, but these recurrences are difficult to predict using clinical or pathological features. A specific genetic alteration, the gene fusion NAB2-STAT6, is considered to be the defining driver mutation, and different fusion variants seem to account for specific clinical and pathological features, but their prognostic value remains controversial. We inspected a series of 83 SFTs with a high rate of recurrence to evaluate the clinical significance of several potential biomarkers in addition to gene fusion. Our findings confirm previous observations and uncover novel associations of molecular alterations with clinical features, adding additional evidence for their potential application as molecular biomarkers that are helpful to predict the course of the disease., [Abstract] Risk stratification of solitary fibrous tumor (SFT) patients based on clinicopathological features has limited efficacy, especially in predicting late relapse or metastasis. The hallmark alteration of SFT is the gene fusion NAB2-STAT6, whose prognostic value remains controversial. As biological knowledge of this entity has increased in recent years, new molecular alterations have emerged that could be helpful to refine current risk models. Here, we evaluated NAB2-STAT6 fusion variants and other molecular alterations in a series of 83 SFTs that are enriched in progressing cases. Gene fusion variants were identified by targeted RNA-seq in the whole series, whereas TERT promoter (pTERT) mutations were inspected by Sanger sequencing in a subset of 18 cases. Immunohistochemical assays were performed to assess BCOR and NTRK expression as well as P53 mutation status in 45, 44, and 44 cases, respectively. While confirming the associations of gene fusion variants with clinicopathological parameters, our results do not prove their prognostic value. Pan-TRK immunoexpresion correlated with recurrence/progression, P53 staining associated with higher mitotic counts, and pTERT mutations were enriched in cases with fatal outcome. An intriguing correlation was found for BCOR protein expression with gene fusion variants, size, and tumor location., This research was funded by the Junta de Andalucía (PI-0061-2020) to C.S.-A. and E.A. and the GEIS-Fundación Mari Paz Jiménez Casado (IV beca trienal) to J.D.-M., C.S.-A. was supported by the European Social Fund and the Junta de Andalucía (Talento Doctores 2020, DOC_01473), and J.D.-M. was supported by CIBERONC (CB16/12/00361). E.d.Á.’s laboratory is supported by the ISCIII-FEDER (PI20/00003), CIBERONC (CB16/12/00361), Asociación Pablo Ugarte, Fundación CRIS contra el cancer, Asociación Candela Riera, and Fundación María García Estrada.

Simple Summary A solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that can arise at any body location. Local or distant recurrences occur in a significant proportion of cases, but these recurrences are difficult to predict using clinical or pathological features. A specific genetic alteration, the gene fusion NAB2-STAT6, is considered to be the defining driver mutation, and different fusion variants seem to account for specific clinical and pathological features, but their prognostic value remains controversial. We inspected a series of 83 SFTs with a high rate of recurrence to evaluate the clinical significance of several potential biomarkers in addition to gene fusion. Our findings confirm previous observations and uncover novel associations of molecular alterations with clinical features, adding additional evidence for their potential application as molecular biomarkers that are helpful to predict the course of the disease. Abstract Risk stratification of solitary fibrous tumor (SFT) patients based on clinicopathological features has limited efficacy, especially in predicting late relapse or metastasis. The hallmark alteration of SFT is the gene fusion NAB2-STAT6, whose prognostic value remains controversial. As biological knowledge of this entity has increased in recent years, new molecular alterations have emerged that could be helpful to refine current risk models. Here, we evaluated NAB2-STAT6 fusion variants and other molecular alterations in a series of 83 SFTs that are enriched in progressing cases. Gene fusion variants were identified by targeted RNA-seq in the whole series, whereas TERT promoter (pTERT) mutations were inspected by Sanger sequencing in a subset of 18 cases. Immunohistochemical assays were performed to assess BCOR and NTRK expression as well as P53 mutation status in 45, 44, and 44 cases, respectively. While confirming the associations of gene fusion variants with clinicopathological parameters, our results do not prove their prognostic value. Pan-TRK immunoexpresion correlated with recurrence/progression, P53 staining associated with higher mitotic counts, and pTERT mutations were enriched in cases with fatal outcome. An intriguing correlation was found for BCOR protein expression with gene fusion variants, size, and tumor location.

INTRODUCTION AND OBJECTIVE:Lymph node (LN) status is a key prognostic factor in the decision-making process for prostate cancer (PC) management. Sectioning and haematoxylin-eosin (HE) staining tech...

Ewing sarcoma, a highly aggressive bone and soft-tissue cancer, is considered a prime example of the paradigms of a translocation-positive sarcoma: a genetically rather simple disease with a specific and neomorphic-potential therapeutic target, whose oncogenic role was irrefutably defined decades ago. This is a disease that by definition has micrometastatic disease at diagnosis and a dismal prognosis for patients with macrometastatic or recurrent disease. International collaborations have defined the current standard of care in prospective studies, delivering multiple cycles of systemic therapy combined with local treatment; both are associated with significant morbidity that may result in strong psychological and physical burden for survivors. Nevertheless, the combination of non-directed chemotherapeutics and ever-evolving local modalities nowadays achieve a realistic chance of cure for the majority of patients with Ewing sarcoma. In this review, we focus on the current standard of diagnosis and treatment while attempting to answer some of the most pressing questions in clinical practice. In addition, this review provides scientific answers to clinical phenomena and occasionally defines the resulting translational studies needed to overcome the hurdle of treatment-associated morbidities and, most importantly, non-survival.

The effectiveness of targeted therapies with tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC) depends on the accurate determination of the genomic status of the tumour. For this reason, molecular analyses to detect genetic rearrangements in some genes (ie

The recent identification of rearrangements of neurotrophic tyrosine receptor kinase (NTRK) genes and the development of specific fusion protein inhibitors, such as larotrectinib and entrectinib, have revolutionized the diagnostic and clinical management of patients presenting with tumours with these alterations. Tumours that harbour NTRK fusions are found in both adults and children and are either rare tumours with common NTRK fusions that may be diagnostic, or more common tumours with rare NTRK fusions. To assess the currently available evidence, 3key Spanish medical societies (the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Pathology (SEAP) and the Spanish Society of Paediatric Haematology and Oncology (SEHOP) have brought together a group of experts to develop a consensus document that includes guidelines on the diagnostic, clinical and therapeutic aspects of NTRK-fusion tumours. It also discusses the challenges related to the routine detection of these genetic alterations in a mostly public health care system.

A spotlight has been shone on endoglin in recent years due to that fact of its potential to serve as both a reliable disease biomarker and a therapeutic target. Indeed, endoglin has now been assigned many roles in both physiological and pathological processes. From a molecular point of view, endoglin mainly acts as a co-receptor in the canonical TGFβ pathway, but also it may be shed and released from the membrane, giving rise to the soluble form, which also plays important roles in cell signaling. In cancer, in particular, endoglin may contribute to either an oncogenic or a non-oncogenic phenotype depending on the cell context. The fact that endoglin is expressed by neoplastic and non-neoplastic cells within the tumor microenvironment suggests new possibilities for targeted therapies. Here, we aimed to review and discuss the many roles played by endoglin in different tumor types, as well as the strong evidence provided by pre-clinical and clinical studies that supports the therapeutic targeting of endoglin as a novel clinical strategy. H.P. Departamento de Defensa de EE. UU. W81XWH-16-1-0131 Fundación Proyecto Neurofibromatosis. T.G.M.FPU (Ministerio de Ciencia, Innovación y Universidades, Gobierno de España). Retos-Colaboración RTC-2014-2102-1 y PI17-000464 de MINECO-FEDER

Ewing sarcoma (EWS) is an aggressive developmental sarcoma driven by a fusion gene, EWSR1-FLI1. However, little is known about the regulation of EWSR1-FLI1 chimeric fusion gene expression. Here, we demonstrate that active nuclear HDAC6 in EWS modulates acetylation status of specificity protein 1 (SP1), consequently regulating SP1/P300 activator complex binding to EWSR1 and EWSR1-FLI1 promoters. Selective inhibition of HDAC6 impairs binding of activator complex SP1/P300, thereby inducing EWSR1-FLI1 downregulation and significantly reducing its oncogenic functions. In addition, sensitivity of EWS cell lines to HDAC6 inhibition is higher than other tumor or non-tumor cell lines. Overexpression of HDAC6 in primary EWS tumor clinical samples correlates with a poor prognosis. Notably, a combination treatment of a selective HDAC6 inhibitor and doxorubicin (standard of care in EWS) dramatically inhibits tumor growth in two EWS murine xenograft models. These results could lead to suitable and promising therapeutic alternatives for EWS patients.

Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor of children and young adults in which the principal driver is a fusion gene, EWSR1-FLI1. Although the essential role of EWSR1-FLI1 protein in the regulation of oncogenesis, survival, and tumor progression processes has been described in-depth, little is known about the regulation of chimeric fusion-gene expression. Here, we demonstrate that the active nuclear HDAC6 in EWS modulates the acetylation status of specificity protein 1 (SP1), consequently regulating the SP1/P300 activator complex binding to EWSR1 and EWSR1-FLI1 promoters. Selective inhibition of HDAC6 impairs binding of the activator complex SP1/P300, thereby inducing EWSR1-FLI1 downregulation and significantly reducing its oncogenic functions. In addition, sensitivity of EWS cell lines to HDAC6 inhibition is higher than other tumor or non-tumor cell lines. High expression of HDAC6 in primary EWS tumor samples from patients correlates with a poor prognosis in two independent series accounting 279 patients. Notably, a combination treatment of a selective HDAC6 and doxorubicin (a DNA damage agent used as a standard therapy of EWS patients) dramatically inhibits tumor growth in two EWS murine xenograft models. These results could lead to suitable and promising therapeutic alternatives for patients with EWS., Research in the E.D.A. lab is supported by Asociación Española Contra el Cáncer (AECC), the Ministry of Science of Spain-FEDER (CIBERONC, PI1700464, PI2000003, RD06/0020/0059)S. D.G.D. and L.H.P. are supported by CIBERONC (CB16/12/00361). D.G.D., M.J.R. and L.H.P. are PhD researchers funded by the Consejería de Salud, Junta de Andalucía (PI-0197-2016, ECAI F2-0012-2018 and PI-0013-2018, respectively).

Sarcomas are malignant soft tissue and bone tumours affecting adults, adolescents and children. They represent a morphologically heterogeneous class of tumours and some entities lack defining histopathological features. Therefore, the diagnosis of sarcomas is burdened with a high inter-observer variability and misclassification rate. Here, we demonstrate classification of soft tissue and bone tumours using a machine learning classifier algorithm based on array-generated DNA methylation data. This sarcoma classifier is trained using a dataset of 1077 methylation profiles from comprehensively pre-characterized cases comprising 62 tumour methylation classes constituting a broad range of soft tissue and bone sarcoma subtypes across the entire age spectrum. The performance is validated in a cohort of 428 sarcomatous tumours, of which 322 cases were classified by the sarcoma classifier. Our results demonstrate the potential of the DNA methylation-based sarcoma classification for research and future diagnostic applications., This work was funded by Deutsche Krebshilfe grant 70112499, the NCT Heidelberg and an Illumina Medical Research Grant. Part of this work was funded by the National Institute of Health Research (to S.B. and Z.J.) and to UCLH Biomedical research centre (BRC399/NS/RB/101410). Human tissues were obtained from University College London NHS Foundation Trust as part of the UK Brain Archive Information Network (BRAIN UK, Ref: 18/004) which is funded by the Medical Research Council and Brain Tumour Research UK. The methylation profiling at NYU is supported by a grant from the Friedberg Charitable Foundation (to M.Sn.). M.Mi. would like to thank the Luxembourg National Research Fond (FNR) for the support (FNR PEARL P16/BM/11192868 grant). Open Access funding enabled and organized by Projekt DEAL.

KIT/PDGFRA oncogenic tyrosine kinase signaling is the central oncogenic event in most gastrointestinal stromal tumors (GIST), which are human malignant mesenchymal neoplasms that often feature myogenic differentiation. Although targeted inhibition of KIT/PDGFRA provides substantial clinical benefit, GIST cells adapt to KIT/PDGFRA driver suppression and eventually develop resistance. The specific molecular events leading to adaptive resistance in GIST remain unclear. By using clinically representative in vitro and in vivo GIST models and GIST patients’ samples, we found that the E3 ubiquitin ligase Atrogin-1 (FBXO32)—the main effector of muscular atrophy in cachexia—resulted in the most critical gene derepressed in response to KIT inhibition, regardless the type of KIT primary or secondary mutation. Atrogin-1 in GISTs is transcriptionally controlled by the KIT-FOXO3a axis, thus indicating overlap with Atrogin-1 regulation mechanisms in nonneoplastic muscle cells. Further, Atrogin-1 overexpression was a GIST-cell-specific pro-survival mechanism that enabled the adaptation to KIT-targeted inhibition by apoptosis evasion through cell quiescence. Buttressed on these findings, we established in vitro and in vivo the preclinical proof-of-concept for co-targeting KIT and the ubiquitin pathway to maximize the therapeutic response to first-line imatinib treatment., This project was funded by the 2014 SARC International Career Development Award (SARC Sarcoma Spore 1U54CA168512–01), Fundación Mari Paz Jiménez Casado, FERO Foundation, Spanish Society of Medical Oncology (SEOM), PERIS SLT006/17/221, ISCIII PI16/01371 and PI19/01271, all to C.S. ISCIII FI20/00275 (to DG-P), and a Ph.D. fellowship from the National Secretary for Higher Education, Science, Technology and Innovation of Ecuador (SENESCYT) (to DFP-J). AE-C is funded by ISCIII PT17/0009/0019 and co-funded by FEDER.

The diagnosis of Ewing sarcoma requires the integration of the information generated from numerous techniques, some of them being very sophisticated. However, the first steps of the diagnostic process are crucial to achieve the maximum possible diagnostic performance. In this chapter we will review how to handle the diagnostic specimen from its collection, how to prepare it for diagnosis, how to make a complete pathology report, and provide guidance for the reasonable use of immunohistochemical techniques in this malignancy.

The diagnosis of Ewing sarcoma requires the integration of the information generated from numerous techniques, some of them being very sophisticated. However, the first steps of the diagnostic process are crucial to achieve the maximum possible diagnostic performance. In this chapter we will review how to handle the diagnostic specimen from its collection, how to prepare it for diagnosis, how to make a complete pathology report, and provide guidance for the reasonable use of immunohistochemical techniques in this malignancy.

The Rosetta Stone of the new era of biomedicine includes five essential ideas to understand the real concept of precision medicine (PM): preventive, predictive, personalized, participatory (1), and pertinent. The application of these five “Ps” is currently the Holy Grail of the clinical routine and particularly important for cancer are the concepts of prediction and personalization. It is especially significant in those diseases characterized by higher biological heterogeneity, as it is the case of lung cancer. Obviously, an improvement of biological knowledge must be accompanied by technological breakthroughs. In the last years, new molecular analysis technologies characterized by high specificity and sensitivity rates are being developed, allowing detection of rare clonal sub-types with low allelic frequency. However, the specificity and sensitivity present high variability among platforms, what is of particular importance for the detection of very low allelic frequency mutations. In fact, it has been accepted that variants with a low allele frequency affect the accuracy of mutation detection methodologies (2). Moreover, the variability in the limits of detection (LoD) is especially important for a correct treatment choice as well as an efficient stratification of patients susceptible to be treated with a particular therapy. Therefore, selection of methodologies with ability to discriminate between high and low allelic frequencies is essential for a correct application of PM. In the case of lung cancer, there are several mutation-targeting strategies for personalized treatments among which, tyrosine kinase inhibitors (TKI) are a widely used anti-cancer strategy. The key target of these drugs is the EGFR gene that, when overexpressed, activates cell survival and proliferation pathways. The success or failure of TKI treatments usually relies on presence or absence of sensitizing mutations respectively but together with them also treatment-resistant mutations might play a role (3). The most common resistance mutation is EGFR T790M so screening for this mutation offers information on whether the patient is candidate or not for TKI treatments.

This commentary addresses the issue of the classification of sarcomas in the article written by Watson and colleagues published recently in this journal. The article delves into the molecular characterization and distinct phenotypes of some recently described entities (e.g. BCOR-rearranged sarcomas, CIC-fused sarcomas) and describes new groups with common characteristics. This commentary focuses on several questions raised in the article, such as what makes a group of sarcomas become a clinical entity, which should be the main driver of sarcoma classification, how the classification of small round cell sarcomas is expected to evolve and how high-throughput techniques could be applied to sarcoma diagnosis in the short term. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

[Purpose] Epigenetic regulation is crucial in mammalian development and maintenance of tissue-cell specific functions. Perturbation of epigenetic balance may lead to alterations in gene expression, resulting in cellular transformation and malignancy. Previous studies in Ewing sarcoma (ES) have shown that the Nucleosome Remodeling Deacetylase (NuRD) complex binds directly to EWS-FLI1 oncoprotein and modulates its transcriptional activity. The role of EWS-FLI1 as a driver of proliferation and transformation in ES is widely known, but the effect of epigenetic drugs on fusion activity remains poorly described. The present study evaluated the combination effects of the histone deacetylases inhibitor suberoylanilide hydroxamic acid (SAHA) and Lysine-specific demethylase1 inhibitor (HCI-2509) on different biological functions in ES and in comparison to monotherapy treatments., [Results] The study of proliferation and cell viability showed a synergistic effect in most ES cell lines analyzed. An enhanced effect was also observed in the induction of apoptosis, together with accumulation of cells in G1 phase and a blockage of the migratory capacity of ES cell lines. Treatment, either in monotherapy or in combination, caused a significant decrease of EWS-FLI1 mRNA and protein levels and this effect is mediated in part by fusion gene promoter regulation. The anti-tumor effect of this combination was confirmed in patient-derived xenograft mouse models, in which only the combination treatment led to a statistically significant decrease in tumor volume., [Conclusions] The combination of SAHA and HCI-2509 is proposed as a novel treatment strategy for ES patients to inhibit the essential driver of this sarcoma and tumor growth., Research in EDA, JM, and OMT labs is supported by Asociación Española Contra el Cáncer (AECC). Enrique de Alava’s lab is also supported by the Ministry of Economy and Competitiveness of Spain-FEDER (CIBERONC, PI11700464, RD06/0020/0059, FMGE) and the European Commission (FP7-HEALTH-2011-two-stage, Project ID278742 EUROSARC). DGD and LHP are supported by Red Temática de Investigación Cooperativa en Cáncer (RD12/0036/0017) and Centro de Investigación Biomédica en Red de Cáncer (CB16/12/00361)S. PRN is supported by a grant from the María García Estrada Foundation. DGD is a PhD researcher funded by the Consejería de Salud, Junta de Andalucía (PI-0197-2016). MJR is supported by the Consejería de Salud, Junta de Andalucía (ECAIF2-0176-2013).

Ewing sarcoma (ES) is the second most common bone malignancy affecting children and young adults with poor prognosis due to high metastasis incidence. Our group previously described that EphA2, a tyrosine kinase receptor, promotes angiogenesis in Ewing sarcoma (ES) cells via ligand-dependent signaling. Now we wanted to explore EphA2 ligand-independent activity, controlled upon phosphorylation at S897 (p-EphA2S897 ), as it has been linked to metastasis in several malignancies. By reverse genetic engineering we explored the phenotypic changes after EphA2 removal or reintroduction. Gene expression microarray was used to identify key players in EphA2 signaling. Mice were employed to reproduce metastatic processes from orthotopically implanted engineered cells. We established a correlation between ES cells aggressiveness and p-EphA2S897 . Moreover, stable overexpression of EphA2 in low EphA2 expression ES cells enhanced proliferation and migration, but not a non-phosphorylable mutant (S987A). Consistently, silencing of EphA2 reduced tumorigenicity, migration and invasion in vitro, and lung metastasis incidence in experimental and spontaneous metastasis assays in vivo. A gene expression microarray revealed the implication of EphA2 in cell signaling, cellular movement and survival. ADAM19 knockdown by siRNA technology strongly reproduced the negative effects on cell migration observed after EphA2 silencing. Altogether, our results suggest that p-EphA2S897 correlates with aggressiveness in ES, so blocking its function may be a promising treatment.

Rhabdomyosarcoma (RMS) is the most common soft tissue malignancy in childhood and adolescence. Patients with the most aggressive histological variant have an unfavorable prognosis due to a high metastasis incidence. Lysyl oxidase-like 2 (LOXL2) is a lysyl oxidase, member of a family of extracellular matrix (ECM) crosslinking enzymes that recently have emerged as important regulators of tumor progression and metastasis. We report that LOXL2 is overexpressed in RMS, suggesting a potential role for LOXL2 in RMS oncogenic progression. Consistently, transient and stable LOXL2 knockdown decreased cell migratory and invasive capabilities in two ARMS cell lines. Furthermore, introduction of LOXL2 in RMS non-expressing cells using wild type or mutated (catalytically inactive) constructs resulted in increased cell migration, cell invasion and number and incidence of spontaneous lung metastasis in vivo, independently of its catalytic activity. To further study the molecular mechanism associated with LOXL2 expression, a pull-down assay on LOXL2-transfected cells was performed and analyzed by mass spectrometry. The intermediated filament protein vimentin was validated as a LOXL2-interactor. Thus, our results suggest an oncogenic role of LOXL2 in RMS by regulating cytoskeleton dynamics and cell motility capabilities., OMT: Fundación Alba Pérez lucha contra el cáncer infantil. Instituto de Salud Carlos III (CES12/021; PI11/00038; PI15/00035; AC14/00026) and EU's Fondo Europeo de Desarrollo Regional (FEDER) “Una manera de hacer Europa/A way to achieve Europe.” CERCA Program/Generalitat de Catalunya (2017SGR332). OA-R, DH-M: Fundación Científica de la AECC. SG-M, SR-V: Fundación Alba Pérez lucha contra el cáncer infantil. PM: European Union’s Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant agreement ITN: 766214 – ESR 4.

Ewing sarcoma is a bone and soft tissue tumor predominantly affecting adolescents and young adults. To characterize changes in anticancer drug activity and intratumor drug distribution during the evolution of Ewing sarcomas, we used immunodeficient mice to establish pairs of patient-derived xenografts (PDX) at early (initial diagnosis) and late (relapse or refractory progression) stages of the disease from three patients. Analysis of copy number alterations (CNA) in early passage PDX tissues showed that two tumor pairs established from patients which responded initially to therapy and relapsed more than one year later displayed similar CNAs at early and late stages. For these two patients, PDX established from late tumors were more resistant to chemotherapy (irinotecan) than early counterparts. In contrast, the tumor pair established at refractory progression showed highly dissimilar CNA profiles, and the pattern of response to chemotherapy was discordant with those of relapsed cases. In mice receiving irinotecan infusions, the level of SN-38 (active metabolite of irinotecan) in the intracellular tumor compartment was reduced in tumors at later stages compared to earlier tumors for those pairs bearing similar CNAs, suggesting that distribution of anticancer drug shifted toward the extracellular compartment during clonal tumor evolution. Overexpression of the drug transporter P-glycoprotein in late tumor was likely responsible for this shift in drug distribution in one of the cases., The work at Hospital Sant Joan de Deu was supported by associations of parents and families of children with cancer. The work of EdA was supported by the AECC Scientific Foundation (GCB13-1578), ISCIII-FEDER (PI14/01466 and PI17/00464), CIBERONC (CB16/12/00361), Asociación Pablo Ugarte and Fundación María García Estrada. The work of JM was supported by the AECC Scientific Foundation (GCB13-1578) and Asociación Pablo Ugarte. The work of AMC was supported by grants from the AECC Scientific Foundation, MINECO (SAF2011-22660), Fundacion BBVA (152/2011), the European Union Seventh Framework Programme (FP7/2007-2013) under Marie Curie International Reintegration Grant (PIRG-08-GA-2010-276998) and ISCIII-FEDER (CP13/00189 and CPII18/00009).

[Background] Solitary fibrous tumour is an ultra-rare sarcoma, which encompasses different clinicopathological subgroups. The dedifferentiated subgroup shows an aggressive course with resistance to pazopanib, whereas in the malignant subgroup, pazopanib shows higher activity than in previous studies with chemotherapy. We designed a trial to test pazopanib activity in two different cohorts of solitary fibrous tumour: the malignant-dedifferentiated cohort, which was previously published, and the typical cohort, which is presented here., [Methods] In this single-arm, phase 2 trial, adult patients (aged ≥18 years) diagnosed with confirmed metastatic or unresectable typical solitary fibrous tumour of any location, who had progressed in the previous 6 months (by Choi criteria or Response Evaluation Criteria in Solid Tumors [RECIST]) and an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2 were enrolled at 11 tertiary hospitals in Italy, France, and Spain. Patients received pazopanib 800 mg once daily, taken orally, until progression, unacceptable toxicity, withdrawal of consent, non-compliance, or a delay in pazopanib administration of longer than 3 weeks. The primary endpoint was proportion of patients achieving an overall response measured by Choi criteria in patients who received at least 1 month of treatment with at least one radiological assessment. All patients who received at least one dose of the study drug were included in the safety analyses. This study is registered in ClinicalTrials.gov, NCT02066285, and with the European Clinical Trials Database, EudraCT 2013-005456-15., [Findings] From June 26, 2014, to Dec 13, 2018, of 40 patients who were assessed, 34 patients were enrolled and 31 patients were included in the response analysis. Median follow-up was 18 months (IQR 14–34), and 18 (58%) of 31 patients had a partial response, 12 (39%) had stable disease, and one (3%) showed progressive disease according to Choi criteria and central review. The proportion of overall response based on Choi criteria was 58% (95% CI 34–69). There were no deaths caused by toxicity, and the most frequent adverse events were diarrhoea (18 [53%] of 34 patients), fatigue (17 [50%]), and hypertension (17 [50%])., [Interpretation] To our knowledge, this is the first prospective trial of pazopanib for advanced typical solitary fibrous tumour. The manageable toxicity and activity shown by pazopanib in this cohort suggest that this drug could be considered as first-line treatment for advanced typical solitary fibrous tumour., Spanish Group for Research on Sarcomas (GEIS), Italian Sarcoma Group (ISG), French Sarcoma Group (FSG), GlaxoSmithKline, and Novartis.

The presence of the chimeric EWSR1-FLI1 oncoprotein is the main and initiating event defining Ewing sarcoma (ES). The dysregulation of epigenomic and proteomic homeostasis induced by the oncoprotein contributes to a wide variety of events involved in oncogenesis and tumor progression. Attempts at studying the effects of EWSR1-FLI1 in non-tumor cells to understand the mechanisms underlying sarcomagenesis have been unsuccessful to date, as ectopic expression of EWSR1-FLI1 blocks cell cycle progression and induces apoptosis in the tested cell lines. Therefore, it is essential to find a permissive cell type for EWSR1-FLI1 expression that allows its endogenous molecular functions to be studied. Here we have demonstrated that HeLa cell lines are permissive to EWSR1-FLI1 ectopic expression, and that our model substantially recapitulates the endogenous activity of the EWSR1-FLI1 fusion protein. This model could contribute to better understanding ES sarcomagenesis by helping to understand the molecular mechanisms induced by the EWSR1-FLI1 oncoprotein., Research in the EDA lab is supported by Asociación Española Contra el Cáncer (AECC). Enrique de Alava’s lab is also supported by the Ministry of Economy and Competitiveness of Spain-FEDER (CIBERONC, PI11700464, RD06/0020/0059) and the European Commission (FP7-HEALTH-2011-two-stage, Project ID278742 EUROSARC). DGD and LHP are supported by CIBERONC (CB16/12/00361). DGD is a PhD researcher funded by the Consejería de Salud, Junta de Andalucía (PI-0197-2016). LHP is a PhD researcher funded by the Consejería de Salud, Junta de Andalucía (PI-0013-2018). The funder Vitro SA provided support in the form of salaries for the author CM but had no additional roles in the study design, data collection, data analyses, decision to publish or manuscript preparation. The specific roles of this author (CM) are articulated in the ‘author contributions’ section.

[Background] Sarcomas exhibit low expression of factors related to immune response, which could explain the modest activity of PD-1 inhibitors. A potential strategy to convert a cold into an inflamed microenvironment lies on a combination therapy. As tumor angiogenesis promotes immunosuppression, we designed a phase Ib/II trial to test the double inhibition of angiogenesis (sunitinib) and PD-1/PD-L1 axis (nivolumab)., [Methods] This single-arm, phase Ib/II trial enrolled adult patients with selected subtypes of sarcoma. Phase Ib established two dose levels: level 0 with sunitinib 37.5 mg daily from day 1, plus nivolumab 3 mg/kg intravenously on day 15, and then every 2 weeks; and level −1 with sunitinib 37.5 mg on the first 14 days (induction) and then 25 mg per day plus nivolumab on the same schedule. The primary endpoint was to determine the recommended dose for phase II (phase I) and the 6-month progression-free survival rate, according to Response Evaluation Criteria in Solid Tumors 1.1 (phase II)., [Results] From May 2017 to April 2019, 68 patients were enrolled: 16 in phase Ib and 52 in phase II. The recommended dose of sunitinib for phase II was 37.5 mg as induction and then 25 mg in combination with nivolumab. After a median follow-up of 17 months (4–26), the 6-month progression-free survival rate was 48% (95% CI 41% to 55%). The most common grade 3–4 adverse events included transaminitis (17.3%) and neutropenia (11.5%)., [Conclusions] Sunitinib plus nivolumab is an active scheme with manageable toxicity in the treatment of selected patients with advanced soft tissue sarcoma, with almost half of patients free of progression at 6 months., [Trial registration number] NCT03277924., This work was supported by GEIS and ISG. BMS and Pfizer provided drug supply and partial funding for shipping. Translational studies were partially funded by Beca Buesa from the GEIS group.

Ewing sarcoma (EwS) is an aggressive tumor that affects adolescents and young adults. EwS is defined by a chromosomal translocation, EWSR1-FLI1 being the most common, that causes genome reprogramming through remodeling of enhancers. Here, we describe an unexpected function of RING1B, which is highly expressed in EwS. While retaining its repressive activity at Polycomb developmental regulated genes, RING1B colocalizes with EWSR1-FLI1 at active enhancers. We demonstrate that RING1B is necessary for the expression of key EWSR1-FLI1 targets by facilitating oncogene recruitment to their enhancers. Knockdown of RING1B impairs growth of tumor xenografts and expression of genes regulated by EWSR1-FLI1 bound enhancers. Pharmacological inhibition of AURKB with AZD1152 increases H2Aub levels causing down-regulation of RING1B/EWSR1-FLI1 common targets. Our findings demonstrate that RING1B is a critical modulator of EWSR1-FLI1–induced chromatin remodeling, and its inhibition is a potential therapeutic strategy for the treatment of these tumors., S.S.-M. and the project were supported by the Spanish Association Against Cancer (AECC) consolidated groups grant (GCB13131578) consortium. The project also had the support from the Asociacion Pablo Ugarte (APU). E.F.-B. was supported by the Spanish government grant, Instituto de Salud Carlos III (PI16/00245) to J.M. The work in the Di Croce laboratory was supported by grants from the Spanish of Economy, Industry and Competitiveness (MEIC) (BFU2016-75008-P), and Fundacion Vencer El Cancer (VEC).