PDCD1LG2 and synovial sarcoma: PD-L1, PD-L2, and PD-1 expression patterns were examined in a musculoskeletal tumor TMA (234 cases), including osteosarcoma (62 cases), chondrosarcoma (31 cases), synovial sarcoma (127 cases), and GCT (14 cases), using IHC.