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British Journal of Cancer (2013) 109, 22792285 | doi: 10.1038/bjc.2013.547
Keywords: synovial sarcoma; SS18-SSX 1; SS18-SSX 2; survival analysis
The clinical implication of SS18-SSX fusion gene in synovial sarcoma
T Ren1,2, Q Lu1,2, W Guo*,1, Z Lou1, X Peng1, G Jiao1 and Y Sun1
1Musculoskeletal Tumor Center, Peking University Peoples Hospital, Beijing 100044, China
Background: The aim of this study is to evaluate distribution and clinical impact of the SS18-SSX fusion gene in patients with synovial sarcoma in China.
Methods: We collected and analysed the clinical data of 88 patients using univariate and multivariate survival analysis. HEK 293T and NIH 3T3 cell lines were transfected with the SS18-SSX1 or SS18-SSX2 gene to determine the respective involvement of these fusion genes in cell proliferation and invasion.
Results: Overall survival was significantly better among SS18-SSX2 cases (P 0.001), FNCLCC grade 2 cases (Po0.001), and UICC
stage 1 or 2 (Po0.001) by univariate and multivariate survival analysis. SS18-SSX1-positive cells were more proliferative and invasive
than SS18-SSX2-positive cells.
Conclusion: SS18-SSX fusion type is a significant prognostic factor for patients with synovial sarcoma.
Synovial sarcoma (SS), an aggressive soft tissue sarcoma, occurs at any age but often in young adults and has a predilection for the extremities (Kransdorf, 1995). This tumour accounts for 10% of all soft tissue sarcomas. According to the presence or absence of well-developed glandular epithelial cells, SS can be divided into two major histological types: monophasic and biphasic. More than a quarter of patients succumb to this tumour in the first 5 years after diagnosis, despite the best currently available management (Lewis and Brennan, 1996; Lewis et al, 2000).
Cytogenetically, more than 95% of SS is characterised by the t(X; 18) (p11.2; q11.2) chromosomal translocation, which always represents the fusion of SS18 with either SSX1 or SSX2, or rarely with SSX4 (Ladanyi, 1995; dos Santos et al, 2001; Ladanyi, 2001).The SS18-SSX1 and SS18-SSX2 fusion genes appear to be mutually exclusive in SS, and the fusion type is concordant in primary tumours and metastases and constant over the development of disease (Panagopoulos et al, 2001). Detection of the SS18-SSX fusion gene with reverse-transcriptase polymerase chain reaction (RT-PCR) has been used as a sensitive diagnostic method for SS (van de Rijn et al, 1999; Guillou et...