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Simple Summary: CIC-DUX4-rearranged sarcoma (CDS) is a rare and aggressive soft tissue tumor predominantly affecting young adults for which the only oncogenic driver is the CIC-DUX4 fusion protein, resulting from chromosomal rearrangements. The molecular mechanisms by which CIC-DUX4 drives CDS development remain largely unknown, hindering the development of targeted therapies. This study conducted genome-wide profiling of CIC-DUX4 DNA occupancy and associated chromatin states in CDS cell models and tumors. Our findings reveal CIC-DUX4 as a potent transcriptional activator at its binding sites, facilitated by direct interaction with the acetyltransferase p300. Significantly, inhibiting p300 impedes CDS tumor cell proliferation, suggesting a potential therapeutic avenue. This research enhances understanding of CIC-DUX4-mediated transcriptional regulation and proposes targeting p300 as a promising strategy for the clinical management of CDS. CIC-DUX4-rearranged sarcoma (CDS) is a rare and aggressive soft tissue tumor that occurs most frequently in young adults. The key oncogenic driver of this disease is the expression of the CIC-DUX4 fusion protein as a result of chromosomal rearrangements. CIC-DUX4 displays chromatin binding properties, and is therefore believed to function as an aberrant transcription factor. However, the chromatin remodeling events induced by CIC-DUX4 are not well understood, limiting our ability to identify new mechanism-based therapeutic strategies for these patients. Here, we generated a genome-wide profile of CIC-DUX4 DNA occupancy and associated chromatin states in human CDS cell models and primary tumors. Combining chromatin profiling, proximity ligation assays, as well as genetic and pharmacological perturbations, we show that CIC-DUX4 operates as a potent transcriptional activator at its binding sites. This property is in contrast with the repressive function of the wild-type CIC protein, and is mainly mediated through the direct interaction of CIC-DUX4 with the acetyltransferase p300. In keeping with this, we show p300 to be essential for CDS tumor cell proliferation; additionally, we find its pharmacological inhibition to significantly impact tumor growth in vitro and in vivo. Taken together, our study elucidates the mechanisms underpinning CIC-DUX4-mediated transcriptional regulation. [ABSTRACT FROM AUTHOR]

Background: Patients with metastatic sarcoma have limited treatment options. Nivolumab and ipilimumab are monoclonal antibodies targeting PD-1 and CTLA-4, respectively. We investigated the activity and safety of nivolumab alone or in combination with ipilimumab in patients with locally advanced, unresectable, or metastatic sarcoma.Methods: We did a multicentre, open-label, non-comparative, randomised, phase 2 study that enrolled patients aged 18 years or older and had central pathology confirmation of sarcoma with at least one measurable lesion by Response Evaluation Criteria In Solid Tumors (RECIST) 1.1, evidence of metastatic, locally advanced or unresectable disease, an ECOG performance status of 0-1, and received at least one previous line of systemic therapy. Patients were assigned to treatment in an unblinded manner, as this trial was conducted as two independent, non-comparative phase 2 trials. Enrolled patients were assigned (1:1) via a dynamic allocation algorithm to intravenous nivolumab 3 mg/kg every 2 weeks, or nivolumab 3 mg/kg plus ipilimumab 1 mg/kg every 3 weeks for four doses. Thereafter, all patients received nivolumab monotherapy (3 mg/kg) every 2 weeks for up to 2 years. The primary endpoint was the proportion of patients with locally advanced, unresectable or metastatic soft tissue sarcoma achieving a confirmed objective response. Analysis was per protocol. This study is ongoing although enrolment is closed. It is registered with ClinicalTrials.gov, number NCT02500797.Findings: Between Aug 13, 2015, and March 17, 2016, 96 patients from 15 sites in the USA underwent central pathology review for eligibility and 85 eligible patients, including planned over-enrolment, were allocated to receive either nivolumab monotherapy (43 patients) or nivolumab plus ipilimumab (42 patients). The primary endpoint analysis was done according to protocol specifications in the first 76 eligible patients (38 patients per group). The number of confirmed responses was two (5% [92% CI 1-16] of 38 patients) in the nivolumab group and six (16% [7-30] of 38 patients) in the nivolumab plus ipilimumab group. The most common grade 3 or worse adverse events were anaemia (four [10%] patients), decreased lymphocyte count (three [7%]), and dehydration, increased lipase, pain, pleural effusion, respiratory failure, secondary benign neoplasm, and urinary tract obstruction (two [5%] patients each) among the 42 patients in the nivolumab group and anaemia (eight [19%] patients), hypotension (four [10%] patients), and pain and urinary tract infection (three [7%] patients each) among the 42 patients in the nivolumab plus ipilimumab group. Serious treatment-related adverse events occurred in eight (19%) of 42 patients receiving monotherapy and 11 (26%) of 42 patients receiving combination therapy, and included anaemia, anorexia, dehydration, decreased platelet count, diarrhoea, fatigue, fever, increased creatinine, increased alanine aminotransferase, increased aspartate aminotransferase, hyponatraemia, pain, pleural effusion, and pruritus. There were no treatment-related deaths.Interpretation: Nivolumab alone does not warrant further study in an unselected sarcoma population given the limited efficacy. Nivolumab combined with ipilimumab demonstrated promising efficacy in certain sarcoma subtypes, with a manageable safety profile comparable to current available treatment options. The combination therapy met its predefined primary study endpoint; further evaluation of nivolumab plus ipilimumab in a randomised study is warranted.Funding: Alliance Clinical Trials in Oncology, National Cancer Institute Cancer Therapy Evaluation Program, Bristol-Myers Squibb, Cycle for Survival. [ABSTRACT FROM AUTHOR]

Objective: To determine clinicopathologic factors on survival in patients with head and neck synovial sarcoma.Patients and Methods: We retrospectively identified patients with molecularly confirmed synovial sarcomas of the head and neck (SS-HN), either by the presence of SS18-SSX fusion transcript by RT-PCR or SS18 gene rearrangement by FISH, who were managed at our institution over a 20-year period (1996-2015). Kaplan-Meier survival analysis and log-rank test were performed to evaluate variables related to disease specific survival (DSS). Fisher exact test was performed to evaluate variables related to local recurrence.Results: Thirty-four patients (20 males and 14 females, mean of 31years) with SS18-SSX fusion-positive SS-HN were identified. The parapharyngeal region of the neck was the most common site. The mean tumor size was 4.8cm (0.8-10cm). Two-thirds (n=23) of cases had a monophasic histology. The 2, 5 and 10-year DSS rates were 97%, 79% and 68%. The 5-year DSS rates for the adult/pediatric cohort were 74%/88%. Recurrence showed significant effect on DSS (p=0.021). There was no significant effect on DSS with age, therapy modality, tumor site, surgical margin, tumor size (⩽5cm vs. >5cm) and histopathologic subtype. Tumor site (i.e. skull base/paranasal sinus region) was associated with local recurrence (p=0.003).Conclusion: In our cohort DSS rate was associated with recurrence. Tumors located in the skull base/paranasal sinus region were associated with a higher rate of local recurrence. Thus appropriate selection of high risk patients who can benefit from multimodality therapies might improve survival. [ABSTRACT FROM AUTHOR]

Background: Based on their distinctive histologic and genetic features, the latest WHO classification of soft tissue tumors includes four pathologic variants of rhabdomyosarcoma (RMS): embryonal (ERMS), alveolar (ARMS), spindle cell-sclerosing (SRMS-ScRMS) and pleomorphic RMS. The aim of this study focused on a detailed clinicopathologic and survival analysis of head and neck RMS (HNRMS) using the latest pathologic and molecular criteria reflecting this new subclassification in a large cohort.Patients and Methods: Patients managed for HNRMS in our institution (1996-2015) were analyzed. The presence of a FOXO1 fusion was required for the classification of ARMS. MYOD1 mutations in SRMS-ScRMS were tested when material available. Univariate and multivariate analyses were performed to evaluate variables related to overall survival (OS).Results: Ninety-nine HNRMS patients (52 males and 47 females, mean of 16years) were included in the study after pathologic re-review. The most common location was parameningeal (PM) (n=64), followed by non-orbital/non-PM (n=25) and orbital (n=10). There were 53 ERMS, 33 fusion-positive ARMS and 13 SRMS-ScRMS [SRMS (8); ScRMS (5)]. The 5-year OS rate for ERMS patients was significantly higher (82%) compared to ARMS (53%) and SRMS-ScRMS (50%) [SRMS (75%); ScRMS (30%)]. Univariate analysis showed that survival was dependent on histology (P=0.012), tumor size >5cm (P<0.001), regional lymph node involvement (P=0.002), metastasis at initial presentation (P<0.001), stage (P<0.001), and recurrence (P=0.002). Multivariate analysis confirmed histologic subtype to be significant (P=0.043).Conclusion: Our findings reinforce that HNRMS is a heterogenous disease with ARMS and SRMS-ScRMS having an equally unfavorable outcome. [ABSTRACT FROM AUTHOR]

Increasingly, human mesenchymal malignancies are being classified by the abnormalities that drive their pathogenesis. Although many of these aberrations are highly prevalent within particular sarcoma subtypes, few are currently targeted therapeutically. Indeed, most subtypes of sarcoma are still treated with traditional therapeutic modalities, and in many cases sarcomas are resistant to adjuvant therapies. In this Review, we discuss the core molecular determinants of sarcomagenesis and emphasize the emerging genomic and functional genetic approaches that, coupled with novel therapeutic strategies, have the potential to transform the care of patients with sarcoma. [ABSTRACT FROM AUTHOR]

Background: Extraskeletal myxoid chondrosarcoma (EMC) is a genetically distinct sarcoma with a propensity for local recurrence and metastasis despite an indolent course. To the authors' knowledge, there are limited data examining chemotherapy outcomes as a guide to therapeutic decisions for unresectable disease.Methods: The clinical behavior and treatment responses of 87 patients with EMC who were seen at 2 institutions between 1975 and 2008 were examined.Results: The median age of the patients at the time of diagnosis was 49.5 years, with a male-to-female ratio of 2:1. For patients presenting without metastases, 37% developed local recurrence (median time of 3.3 years) and 26% developed distal recurrence (median time of 3.2 years). Approximately 13% of patients presented with metastases. The 5-year, 10-year, and 15-year overall survival rates were 82%, 65%, and 58%, respectively. Twenty-one patients received 32 evaluable courses of chemotherapy. No significant radiologic or clinical responses were noted. The median time to disease progression while receiving chemotherapy was 5.2 months. The best physician-assessed response to chemotherapy was stable disease for at least 6 months in 25% of patients, stable disease for <6 months in 41% of patients, and disease progression in 34% of patients. The estimated progression-free survival rates at 3 months, 4 months, 6 months, and 9 months were 69%, 65%, 40%, and 26%, respectively.Conclusions: This retrospective review highlights the poor response rate to chemotherapy and emphasizes aggressive control of localized disease as the primary approach to management. Although there are biases inherent in retrospective analyses, these data provide a benchmark for time to disease progression for the study of new agents for the treatment of patients with this diagnosis. [ABSTRACT FROM AUTHOR]

The purpose of this review was to determine whether imatinib mesylate (STI571, Gleevec) has a role in the treatment of osteosarcoma. The expression of platelet-derived growth factor (PDGF) receptor and its ligand was examined in a panel of surgical specimens obtained from 54 osteosarcoma patients, and then the expression was compared with prognosis. The effects of imatinib mesylate on growth and molecular events in 10 patient-derived osteosarcoma cell cultures were investigated. Immunohistochemical studies demonstrated frequent expression of PDGF-AA (80.4%) and PDGF-alpha receptor (79.6%) and their correlation with inferior event-free survival (P < .05). PDGF-B-B and PDGF-beta-receptor expressions were also frequent (75.4% and 86%, respectively); however, statistically significant inferior event-free survival was not demonstrated (P = .15). In vitro studies demonstrated that imatinib mesylate had a variable cytotoxic effect on various osteosarcoma primary cultures, with an IC(50) of 5.6 microM to 9.5 microM, and blocked the PDGF-induced intracellular signal transduction as well as inhibition of downstream Akt phosphorylation. Mitogen-activated protein kinase (MAPK) was constitutively activated despite PDGF stimulation and imatinib mesylate treatment in 7 of 10 osteosarcoma cultures, perhaps explaining uncontrolled proliferation and relative unresponsiveness to imatinib. Imatinib mesylate could not be viewed as having a role as a single agent at current conventional doses for the treatment of osteosarcoma. These findings predicted activity in osteosarcoma clinical trials and suggested that in vitro model systems predict clinical behavior and that PDGF and its receptor expression could potentially be used for determining prognosis of osteosarcoma. [ABSTRACT FROM AUTHOR]