Published in Cancer Detection and Prevention 2004; 28(4).

Are there geographical differences in the frequency of SYT-SSX1 and SYT-SSX2 chimeric transcripts in synovial sarcoma?

Ira Koković MSca, Matej Bračko MD, PhDa, Rastko Golouh MD, PhDa, Marjolijn Ligtenberg PhDb, Han J.J.M. van Krieken MD, PhDb, Petra Hudler MScc, Radovan Komel PhDc

aDepartment of Pathology, Institute of Oncology, Zaloska 2, SI-1000 Ljubljana, Slovenia; bDepartment of Pathology, UMC St Radboud, HB-6500 Nijmegen, The Netherlands; cFaculty of Medicine, Medical Center for Molecular Biology, Institute of Biochemistry, Vrazov trg 2, SI-1000 Ljubljana, Slovenia

Synovial sarcoma (SS) is characterized by the t(X;18)(p11.2;q11.2) chromosomal translocation, which results in generating either SYT-SSX1, SYT-SSX2 or, infrequently, SYT-SSX4 fusion gene. The ratio of SYT-SSX1:SYT-SSX2 fusions is close to 2:1 in the majority of studies, and SYT-SSX2 fusion has been only rarely observed in biphasic SS. In the present study, we compared two series of patients with SS, Slovenian (37 cases) and Dutch (14 cases), with respect to clinical, pathological and molecular findings. The two groups did not differ with regard to clinicopathological features. Whereas the frequency of different SYT-SSX fusions in the Dutch group was similar to that reported in the literature, we found an unexpectedly high number of tumors with SYT-SSX2 fusion in the Slovenian group. The ratio of SYT-SSX1:SYT-SSX2 fusion was 7:18 for monophasic and 2:7 for biphasic tumors in the Slovenian group. This distribution differs significantly from that observed in the Dutch group in the present study (P = 0.041) as well as from data reported in the recent large multi-institutional study on 243 patients (P = 0.0001). Our findings indicate possible geographical differences in the frequency of two SYT-SSX fusion transcripts in patients with synovial sarcoma.

KEY WORDS: Synovial sarcoma, SYT-SSX fusions, Histology, Geographical difference.