CD274 and osteosarcoma: Moreover, another study also investigated the ability of PD-L1 downregulation with PDT combined with the autophagy inhibitor 3-methyladenine (3-MA) to prevent the long-distance metastasis of osteosarcoma.456 A significant tumor inhibition effect mediated by PDT was found in a partial resection model of osteosarcoma, revealing the potential clinical value of PDT during tumor surgery.