Shulman et al. recently reported that ctDNA can be detected in plasma samples from ~50% of pediatric Ewing sarcoma and osteosarcoma patients35 and Shah et al.29 successfully detected EWSR1 or FOXO1 fusions in patients with Ewing sarcoma or ARMS, respectively. This evidence concerns the gene FOXO1 and alveolar rhabdomyosarcoma.