Compared with normal tissues, B7-H3 is overexpressed in a variety of pediatric solid tumors, including neuroblastoma (1–5), rhabdomyosarcoma (3, 5–7), osteosarcoma (5, 8), Ewing sarcoma (5, 6), Wilms tumor (5), and desmoplastic small round cell tumor (4, 5), as well as in a number of cancers more common in adults (9–13). Here, CD276 is linked to rhabdomyosarcoma.