MYCN and Ewing sarcoma: Finally, one of the most strongly enriched gene sets among genes upregulated in the MYCN-driven tumors is the WHITEFORD_PEDIATRIC_ CANCER_MARKERS gene set, consisting of differentially expressed genes in a panel of xenografts representing eight common pediatric tumors (neuroblastoma, rhabdomyosarcoma, Ewing sarcoma, acute lymphoblastic leukemia, Wilms' tumor, osteosarcoma, medulloblastoma and ependymona), compared with normal tissues12 (Figure 5a).