TP53 and Ewing sarcoma: In the present study, ddPCR was utilized to detect mutations in the IDH2 and TP53 genes in plasma samples from patients with three types of bone sarcomas: an aggressively malignant bone-forming tumor (osteosarcoma), a malignant bone tumor-producing cartilaginous matrix (chondrosarcoma), and a distinctive small round cell sarcoma of bone (Ewing sarcoma).