Apart from the canonical SS18-SSX fusion, this is only the second alternative gene fusion variant described in synovial sarcoma to date, in addition to two cases harboring the SS18L1-SSX1 fusion.
Fluorescence in situ hybridization performed on the cell block demonstrated the presence of SYT (18q11) translocation, supporting the diagnosis of synovial sarcoma.
We demonstrate that BRD9 supports oncogenic mechanisms underlying the SS18-SSX fusion in synovial sarcoma and highlight targeted degradation of BRD9 as a potential therapeutic opportunity in this disease.
A transbronchial biopsy was performed, and immunohistochemical results as well as detection of SYT-SSX1 (SYnovial sarcoma Translocation-Synovial Sarcoma X chromosome breakpoint) transcripts resulted in a diagnosis of synovial sarcoma.
Synovial sarcoma (SS) is characterized by a tumour specific chromosomal translocation t(X;18) (p11;q11) which results in the formation of SYT-SSX1 fusion protein.
These findings explain the skeletal contact frequently observed in human SS and may provide alternate means of enabling SS18-SSX-driven oncogenesis in cells as differentiated as preosteoblasts.
In this study, we conducted proteomic studies using <i>SS18</i>/<i>SSX</i> knockdown in three SS cell lines to identify the regulated proteins associated with SS18/SSX in SS.
We evaluated TLE-1 and CD99 expression in various carcinomas and evaluated the expression of the SS18 (SYT) gene rearrangement (a characteristic biomarker for synovial sarcoma) in tumors with TLE-1 and/or CD99 expression.
Meta-analyses showed that the test of detecting MDM2 amplification by fluorescence in situ hybridization was accurate in differentiating atypical lipomatous tumor/well-differentiated liposarcoma/dedifferentiated liposarcoma from benign tumors (N = 971; sensitivity = 95%, 95% confidence interval [CI] 89-98; specificity = 100%, CI 89-100) or from other STS (N = 347; sensitivity = 99%, CI 72-100; specificity = 90%, CI 78-95); that the test of detecting SS18-SSX fusion by reverse transcription polymerase chain reaction (PCR) was accurate in differentiating synovial sarcoma from other STS (N = 532; sensitivity = 93%, CI 85-96; specificity = 99%, CI 96-100).
This review summarises our current understanding of the function of SS18-SSX and the mechanisms by which it alters the epigenetic landscape of permissive cells to induce transformation and the subsequent development of synovial sarcoma.
Here we demonstrate that SS18-SSX globally hijacks BAF complexes on chromatin to activate an SS transcriptional signature that we define using primary tumors and cell lines.
In addition, ZSTK474 induced apoptosis selectively in Ewing's sarcoma (RD-ES and A673), alveolar rhabdomyosarcoma (SJCRH30) and synovial sarcoma (SYO-1, Aska-SS and Yamato-SS) cell lines, all of which harbor chromosomal translocation and resulting oncogenic fusion genes, <i>EWSR1-FLI1</i>, <i>PAX3-FOXO1</i> and <i>SS18-SSX</i>, respectively.