[Diagnostic value of SYT-SSX fusion gene detection by fluorescence in-situ hybridization for synovial sarcoma].

To establish a method of SYT-SSX fusion gene detection by FISH and to explore its diagnostic value for synovial sarcoma.The presence of SYT-SSX fusion gene was determined by FISH using a tissue microarray containing 62 known synovial sarcomas, 60 non-synovial sarcomas and 133 equivocal synovial sarcomas. FISH results were compared with those of RT-PCR published previously.Overall, 96.9% (247/255) of the cases were successfully analyzed by FISH. The sensitivity of FISH for known synovial sarcomas was 96.7% (58/60), and the specificity for the non-synovial sarcoma was 100% (59/59). Moreover, SYT-SSX gene fusion was detected in 78.1% (100/128) of the equivocal synovial sarcomas. The concordance rate between FISH and RT-PCR was 83.6% (102/122) in those equivocal synovial sarcomas, and overall 79.7% (106/133) of these cases were confirmed as synovial sarcomas either by RT-PCR or by FISH.The sensitivity and specificity of FISH detection of SYT-SSX fusion gene are high. FISH and RT-PCR are complementary to each other in the confirmation of synovial sarcomas, particularly those questionable cases.