HLA-A and synovial sarcoma: Using TCR repertoire sequencing and transcriptomic analysis, we verified a TCR, Tcr-1, that was of great avidity to enable primary T cells to specifically elicit Pep-4-specific HLA-A*2402-restricted cytotoxicity against SYT-SSX fusion mutation-positive synovial sarcoma cells both in vitro and in vivo.