The aim of our analysis was the evaluation of the prognostic impact of SYT-SSX fusion status and histological grading in synovial sarcoma (SS) of children and adolescents in the context of the consistent multimodal treatment strategy of the CWS (Cooperative Weichteilsarkom Studie; Cooperative Soft Tissue Sarcoma Study Group) and in comparison with other risk factors.
A specific translocation in this sarcoma induces fusion of the SYT gene on chromosome 18 to the SSX genes on chromosome X, leading to proliferation of the tumor cells.
As one of the first sarcomas to be defined by the presence of a specific chromosomal translocation leading to the production of the SS18-SSX fusion oncogene, it is perhaps the archetypal "translocation-associated sarcoma," and its translocation remains unique to this tumor type.
These results support the notion that the SYT-SSX2 nuclear function and differentiation effects are conserved throughout sarcoma development and are required for its maintenance beyond the initial phase.
This is the first reported case of a remarkable soft tissue sarcoma that exhibits overlapping morphologic features between SS and EMC and that also harbors a combination of SS18-SSX2 and EWS-NR4A3 gene fusions.
Furthermore, tumors were screened for gene fusions (PAX3-FKHR, ASPL-TFE3, and SYT-SSX) previously shown to be associated with MET activation in sarcomas.
In three types of SSs, monophasic fibrous, biphasic and poorly differentiated, NBT/BCIP signals corresponding to SYT-SSX mRNA were uniformly and predominantly positive in the sarcoma cell cytoplasm.
With this method, 27 tumors (9 synovial sarcomas and 18 nonsynovial sarcomas) were studied and showed SYT-SSX1 rearrangement in 6 cases and SYT-SSX2 in 3 cases.
Synovial sarcoma is the most common nonrhabdomyosarcomatous soft tissue sarcoma in children and adolescents and is characterized by a reciprocal t(X;18)(p11;q11) which results in the fusion of the SYT gene on chromosome 18q11 to either of two closely related genes, SSX1 (Xp11.23) or SSX2 (Xp11.21).
We attempted to determine the influence of the two alternative forms of the SYT-SSX fusion gene on tumor morphology and clinical outcome in patients with this sarcoma.