The aim of the present study was to re-evaluate TLE-1 staining and the molecular detection methods of SS18-SSX transcripts for synovial sarcoma. We analyzed TLE-1 expression in 50 molecularly confirmed synovial sarcomas and 85 other soft tissue tumors with three previously published scoring systems. In the present study, 39 to 43 synovial sarcomas showed TLE-1 nuclear staining, whereas 9-15 of 85 other soft tissue tumors showed TLE-1 staining (P < 0.0001). The specificities of strong TLE-1 staining were 100%, 97.6% and 98.8%. The positive likelihood ratio of moderate and strong TLE-1 nuclear expression was >10 in all three scoring systems. There was no difference in TLE-1 staining between different subtypes of synovial sarcoma (P > 0.05). Based on a comparison between conventional reverse transcription (RT)-polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH), quantitative RT-PCR is a more sensitive method than conventional RT-PCR and FISH to detect t(X;18). A positive correlation between TLE-1 staining and SS18-SSX translocation was detected by conventional PCR (P < 0.05). In conclusion, although all three scoring systems could differentiate synovial sarcoma from other soft tissue tumors, diffuse moderate to severe intensity tumors showed the highest specificity in the diagnosis of synovial sarcoma.
Keywords: 18); SS18; SSX; TLE-1; immunohistochemistry; molecular diagnosis; scoring system; synovial sarcoma; t(X.
© 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.