Tuesday 25 November 2003
JRC:6541 : Synovial sarcoma of soft tissues.
Definition: Human synovial sarcomas are aggressive soft tissue tumors with relatively high rates of recurrences and metastases. They display a variable response to common treatment protocols such as radiation and chemotherapy.
- The synovial sarcoma translocation protein SYT-SSX2 recruits beta-catenin to the nucleus and associates with it in an active complex. (16462762)
- Aberrant beta-catenin expression has prognostic relevance. (16740029, 11274633, 11054718)
- +/- Association between aberrant (nuclear) beta-catenin expression and cyclin D1 accumulation (16740029, 16733209)
fusiform cell tumors
- adult-type fibrosarcoma
These three fusion genes account for more than 95% of the synovial sarcomas.
The SS18 and SSX genes encode nuclear proteins that exhibit opposite transcription regulatory activities, likely through epigenetic mechanisms. The SS18 protein functions as a transcriptional coactivator and interacts directly with members of the epigenetic chromatin remodeling and modification machineries.
In contrast, the SSX proteins function as transcriptional corepressors and are associated with several Polycomb group proteins. Since the domains involved in these apparently opposite transcription regulatory activities are retained in the SS18-SSX fusion proteins, these fusion proteins can function as "activator-repressors" of transcription.
- fusiform cell tumors
- biphasic tumors
- synovial tumors
Gene expression profiling of synovial sarcoma: distinct signature of poorly differentiated type. Nakayama R, Mitani S, Nakagawa T, Hasegawa T, Kawai A, Morioka H, Yabe H, Toyama Y, Ogose A, Toguchida J, Nakayama T, Yoshida T, Ichikawa H. Am J Surg Pathol. 2010 Nov;34(11):1599-607. PMID: 20975339
Kanemitsu S, Hisaoka M, Shimajiri S, Matsuyama A, Hashimoto H. Molecular detection of SS18-SSX fusion gene transcripts by cRNA in situ hybridization in synovial sarcoma using formalin-fixed, paraffin-embedded tumor tissue specimens. Diagn Mol Pathol. 2007 Mar;16(1):9-17. PMID: 17471153