These neoantigen peptides successfully induced synovial sarcoma-specific cytotoxic T lymphocytes (CTLs) that specifically killed HLA-A24-positive synovial sarcoma cells containing the SYT-SSX neoantigen as well as the target cells pulsed with these peptides.92–94 A study on head and neck squamous cell carcinomas (HNSCC) found that the tumor’s immune response to anti-PD-1 therapy was mediated by neoantigens generated by DEK-AFF2 fusion. This evidence concerns the gene AFF2 and synovial sarcoma.