This case illustrates the importance of proper procurement of frozen tissue for molecular genetic analysis for the identification of the t(X;18), characteristic of synovial sarcoma.
In conclusion, the SYT-SSX fusion type is not a significant prognostic factor unlike tumor size, followed by histological grade for patients with localized synovial sarcoma in Japan.
The presence of an SYT-SSX gene fusion resulting from the t(X;18) characteristic of synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in three of three tumors in which adequate RNA could be obtained from paraffin blocks.
As a result of the synovial sarcoma associated t(X;18) translocation, the human SYT gene on chromosome 18 is fused to either the SSX1 or the SSX2 gene on the X chromosome.
Molecular analysis detected a fusion gene transcript of synovial sarcoma translocation (SYT) gene from chromosome 18 and synovial sarcoma X chromosome breakpoint 1 (SSX1) gene, which is believed to pathognomonic for synovial sarcoma of joint origin.
Fluorescence in situ hybridization performed on the cell block demonstrated the presence of SYT (18q11) translocation, supporting the diagnosis of synovial sarcoma.
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.
Real-time RT-PCR assays specific for Ewing's sarcoma (EWS-FLI1, EWS-ERG, EWS-ETV1, EWS-ETV4, and EWS-FEV), synovial sarcoma (SYT-SSX1 and SYT-SSX2), and rhabdomyosarcoma (PAX3-FKHR and PAX7-FKHR) were tested across the samples.
Although the specific chromosomal translocation and fusion gene SYT-SSX in synovial sarcoma (SS) has been identified, the molecular mechanism of its tumorigenesis is largely unknown.
Here we report a case of synovial sarcoma with a novel form of the SYT-SSX2 fusion transcript, in which 75 bases were inserted at the common fusion junction.
The prognostic impact of SYT-SSX fusion type and histological grade in pediatric patients with synovial sarcoma treated according to the CWS (Cooperative Weichteilsarkom Studie) trials.
We have previously isolated and characterized a mouse cDNA orthologous to the human synovial sarcoma associated SS18 (formerly named SSXT and SYT) cDNA.
Identification of the t(X;18)(p11.2;q11.2) translocation and detection of the resulting SYT-SSX1 or SYT-SSX2 fusion transcripts are useful diagnostic markers for synovial sarcoma.
In conclusion, the SYT-SSX fusion type is not a significant prognostic factor unlike tumor size, followed by histological grade for patients with localized synovial sarcoma in Japan.