Tissue microarrays for liposarcomas, rhabdomyosarcomas, conventional osteosarcomas and chondrosarcomas were stained for PD-1 and PD-L1, and they observed that the expression of PD-1 in rhabdomyosarcomas was associated with a more progressed stage of the tumor [90]. The gene discussed is PDCD1; the disease is chondrosarcoma.