ATRX and osteosarcoma: Similar to the whole bone tumor cohort, the most common mutated genes in osteosarcoma included TP53, NCOR1, VEGFA, CCND3, GID4, RB1, MAP2K4, CCNE1, ATRX, CDK4, CDKN2A, MYC, and PDGFRA (Figure S4).