Preclinical Analysis of Tasidotin HCl in Ewing's Sarcoma, Rhabdomyosarcoma, Synovial Sarcoma, and Osteosarcoma

11034 Background: Bone sarcomas present a unique diagnostic challenge because of the considerable morphologic overlap between different entities. The choice of optimal treatment, however, is dependent upon accurate diagnosis. Genome-wide DNA methylation profiling has emerged as a new approach to aid in the diagnosis of brain tumors, with diagnostic accuracy exceeding standard histopathology. In this work we developed and validated a methylation based classifier to differentiate between osteosarcoma, Ewing’s sarcoma, and synovial sarcoma. Methods: DNA methylation status of 482,421 CpG sites in 15 osteosarcoma, 10 Ewing’s sarcoma, and 11 synovial sarcoma samples were measured using the Illumina HumanMethylation450 array. From this training set of 36 samples we developed a random forest classifier using the 400 most differentially methylated CpG sites (FDR q value < 0.001). This classifier was then validated on 10 synovial sarcoma samples from TCGA, 86 osteosarcoma samples from TARGET-OS, and 15 Ewing’s sarcoma from a recently published series (Huertas-Martinez et al., Cancer Letters 2016). Results: Methylation profiling revealed three distinct molecular clusters, each enriched with a single sarcoma subtype. Within the validation cohorts, all samples from TCGA were correctly classified as synovial sarcoma (10/10, sensitivity and specificity 100%). All but one sample from TARGET-OS were classified as osteosarcoma (85/86, sensitivity 98%, specificity 100%) and all but one sample from the Ewing’s sarcoma series was classified as Ewing’s sarcoma (14/15, sensitivity 93%, specificity 100%). The single misclassified osteosarcoma sample was classified as Ewing’s sarcoma, and was later determined to be a misdiagnosed Ewing’s sarcoma based on RNA-Seq demonstrating high EWRS1 and ETV1 expression. An additional clinical sample that was misdiagnosed as a synovial sarcoma by initial histolopathology, was accurately recognized as osteosarcoma by the methylation classifier. Conclusions: Osteosarcoma, Ewing’s sarcoma and synovial sarcoma have distinct epigenetic profiles. Our validated methylation-based classifier can be used to provide an accurate diagnosis when histological and standard techniques are inconclusive.

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A multiplex assay for detection of common pediatric sarcoma tumor markers

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.10041 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 10041-10041

Author(s):

R. A. Bender ◽

J. Y. Liu ◽

H. Li ◽

K. Z. Qu ◽

A. D. Sferruzza ◽

...

Keyword(s):

Synovial Sarcoma ◽

Tumor Markers ◽

Ewing’S Sarcoma ◽

Ewing's Sarcoma ◽

Rna Extraction ◽

Multiplex Assay ◽

Round Cell ◽

Rt Pcr ◽

Small Round Cell ◽

Pcr Products

10041 Background: Molecular assays for tumor markers have become an important component in diagnosing pediatric sarcomas and small round cell tumors. We developed a multiplex assay to detect 7 common translocations associated with synovial sarcoma (SYT/SSX1, SYT/SSX2), Ewing's sarcoma (EWS/FLI1, EWS/ERG), rhabdomyosarcoma (PAX3/FKHR, PAX7/FKHR), and small round cell desmoplastic tumors (SRCDT) (EWS/WT1). Methods: 27 samples were analyzed with the multiplex assay: 13 formalin-fixed paraffin-embedded tumor samples, 5 fresh frozen tumor samples, 2 commercial RNA samples (SYT/SSX1, SYT/SSX2), 3 cell line samples (EWS/FLI, EWS/ERG, PAX3/FKHR), 1 synthetic control (PAX7/FKHR), and 3 negative controls. After RNA extraction, RT-PCR was performed using the SuperScript III One-Step RT-PCR System with Platinum Taq DNA Polymerase (Invitrogen, Carlsbad, CA). 12 primers were added to a single master mix to amplify all 7 translocations and an internal control; 1 primer from each pair was fluorescently labeled. After RT-PCR, the PCR products were separated on a genetic analyzer and the translocations identified based on the size of the PCR products and their signal intensity. Samples were also analyzed by our current assay (real-time RT-PCR or standard RT-PCR/gel electrophoresis). Results: The results of our current and multiplex assays were positive for all synthetic controls, cell lines, and commercial RNA samples and were concordant for 15/18 tumor samples: 2/7 synovial sarcoma samples were positive for SYT/SSX1 and 3/7 for SYT/SSX2; 2/6 Ewing's sarcoma samples were EWS/FLI1-positive; 1/1 SRCDT sample was EWS/WT1-positive; and 4/4 rhabdomyosarcoma samples were negative. The 3 discordant samples tested negative with our current assay; the new multiplex assay detected EWS/FLI1 in 1 of these and SYT/SSX2 in 2, in agreement with the histological classification. Conclusions: This multiplex assay can detect 7 translocations commonly found in pediatric soft tissue tumors in a single-tube reaction, with increased clinical sensitivity relative to our current methods. No significant financial relationships to disclose.

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Monophasic Synovial Sarcoma in the Elbow Misclassified but Successfully Treated as Ewing’s Sarcoma with Chemotherapy

Orthopedic Research and Reviews ◽

10.2147/orr.s332441 ◽

2021 ◽

Vol Volume 13 ◽

pp. 241-245

Author(s):

Maria Cecilia Madariaga ◽

Alexander Duke ◽

Syed T Hoda ◽

Fazel Khan

Keyword(s):

Synovial Sarcoma ◽

Ewing’S Sarcoma ◽

Ewing's Sarcoma

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Upper gastrointestinal cancers: Are all carcinomas truly carcinomas?

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.3_suppl.20 ◽

2014 ◽

Vol 32 (3_suppl) ◽

pp. 20-20

Author(s):

Xavier Sagaert ◽

Eric Van Cutsem ◽

Sabine Tejpar ◽

Hans Prenen ◽

Gert De Hertogh ◽

...

Keyword(s):

Targeted Therapy ◽

Synovial Sarcoma ◽

Unusual Case ◽

Ewing’S Sarcoma ◽

Ewing's Sarcoma ◽

Poorly Differentiated ◽

Cancer Types ◽

Gi Cancers ◽

The One ◽

Upper Gastrointestinal

20 Background: Poorly differentiated cancer of the upper GI tract is a challenging diagnosis for the pathologist, who will rely on a positive cytokeratin immunostaining to confirm the epithelial origin of the tumor. Being confronted with a highly unusual case (a poorly differentiated esophageal “carcinoma” with immunophenotypic and genetic sarcoma-like features, arising in the background of high grade Barrett dysplasia), we retrospectively investigated whether other cancer cases displayed the same unusual features. Methods: 34 poorly differentiated GI cancers were selected based on availability of FFPE. All cases were investigated by (1) immunohistochemistry for selected carcinoma and sarcoma markers (prekeratin, NCAM, vimentin, CD99) and by (2) FISH for presence/absence of abnormalities of 2 genes, SYT and EWS, that are frequently rearranged in synovial and Ewing’s sarcoma respectively. Results: 6/34 cases displayed an aberrant immunophenotype, with expression of NCAM, vimentin, and/or CD99. FISH revealed a substantial number (9/34) of SYT and EWS related anomalies: 1 EWS rearrangements, 1 SYT rearrangements, 1 SYT and 1 EWS focal amplification, and 4 aneuploidies. While EWS and SYT are (mostly) fused to ERG or SSX1/2 in Ewing’s and synovial sarcoma respectively, these genes were found to be intact in our EWS and SYT rearranged cases. Conclusions: Our data show that SYT & EWS abnormalities are recurrently occurring in poorly differentiated GI cancers that are (mis?)diagnosed as carcinomas. While EWS rearrangement has previously been described in cancer types other than Ewing’s sarcoma, SYT rearrangement was so far thought to be exclusive to the diagnosis of synovial sarcoma. In addition, EWS/SYT abnormalities in our series seemed to target cancers that are at risk of not responding well to the conventional chemoradiotherapy regimen. Of interest, the one “carcinoma” patient that started this study went into complete remission after being administered a sarcoma targeted therapy. We also infer from our results that good histologic assessment of GI cancers is essential for clinical trials aiming at targeted therapy, as not all carcinomas may present true carcinomas.

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