Project description:We systematically explored the transcriptome of 10 synovial sarcoma (SS) patients. We detected a large number of upregulated and downregulated genes in SS compared to normal tissues, which were mainly involved in cell cycle, metabolic and P53 signaling pathways. Moreover, we identified a multitude of differentially alternative spliced genes, indicating that the deregulation of alternative splicing could be one of main factors contribute to the tumorigenesis of SS. A set of tumor-specific gene fusion pairs were identified in SS. We also detected dozens of differentially expressed circRNAs and their parental genes were enriched in muscle related biological process. The interaction network constructed based on circRNAs, miRNAs and corresponding target genes showed that the differentially expressed circRNAs in SS have the potential to regulate the expression of a number of SS related genes. Collectively, we systematically investigated the abnormal expression profile of SS and gain insights into the molecular mechanism from different views of transcriptome expression changes.
Project description:Synovial Sarcomas (SS) are characterized by the presence of the SS18::SSX fusion gene, which protein product induce chromatin changes through remodeling of the BAF complex (BRG1/BRM-associated factor complex), which leads to widespread alterations in gene expression that drive tumor development and progression. However, there are no comprehensive studies that integrate multi-omics approaches to fully understand the heterogeneity and molecular subtypes of SS. To elucidate the genomic events that drive phenotypic diversity in SS, we performed RNA and targeted DNA sequencing on 91 tumors from 55 patients. Our results were verified by proteomic analysis, public gene expression cohorts and single-cell RNA sequencing. Transcriptome profiling identified three distinct SS subtypes resembling the known histological subtypes: SS subtype I and was characterized by hyperproliferation, evasion of immune detection and a poor prognosis. SS subtype II and was dominated by a vascular-stromal component and had a significantly better outcome. SS Subtype III was characterized by biphasic differentiation, increased genomic complexity and immune suppression mediated by checkpoint inhibition, and poor prognosis despite good responses to neoadjuvant therapy. Chromosomal abnormalities were an independent significant risk factor for metastasis. KRT8 was identified as a key component for epithelial differentiation in biphasic tumors, potentially controlled by OVOL1 regulation. Our multi-omics analysis revealed biological and genetic variability between these subtypes, including key transcriptome patterns and secondary genomic events such as copy number alterations, could be associated with long-term outcomes. Our findings explain the histological grounds for SS classification and indicate that a significantly larger proportion of patients have high risk tumors (corresponding to SS subtype I) than previously believed.