ISL1 and Ewing sarcoma: We identified 88 transcription factors, many of which have been described previously as part of the core regulatory transcription factor circuitry in specific cancer types, such as PHOX2B, TWIST1, and ISL1 in neuroblastoma (Durbin et al., 2018; Selmi et al., 2015); MYOD1 and MYOG in rhabdomyosarcoma (Gryder et al., 2017); NR0B1 in Ewing sarcoma (Kinsey et al., 2006) (Figure 4B; Table S3B).