The transcriptional co-repressor TLE-1 (Transducin-Like Enhancer of Split 1) has been used previously as a marker of synovial sarcoma and other sarcomas of peripheral nerve sheath origin [16, 17], so we tested a purified sarcoma subset with an anti-TLE-1 antibody (Fig 4A and 4B; S8 Fig). Here, TLE1 is linked to synovial sarcoma.