SS18 and synovial sarcoma: evaluated the diagnostic accuracy of two novel antibodies (2), SS18:SSX fusion-specific antibody (clone E9X9V; cat# 72364) and SSX-specific antibody targeting the SSX C-terminus (clone E5A2C; cat# 23855), in decalcified surgical specimens and the outcomes of synovial sarcoma (SS) derived from bone.