CD274 and rhabdomyosarcoma: Using the VENTANA PD-L1 SP263 kit to investigate the expression of PD-L1 in various types of sarcoma, Vargas et al. reported positive PD-L1 expression (≥1%) in 31% of undifferentiated pleomorphic sarcoma, 29% of angiosarcoma, 26% of rhabdomyosarcoma, 18% of myxofibrosarcoma, 11% of leiomyosarcoma and 10% of dedifferentiated liposarcoma [35].