Many CSC culture conditions also include supplements such as MSC stimulatory supplements for Ewing sarcoma CSCs and EGF, bFGF, and B27 for glioblastoma and rhabdomyosarcoma CSCs (Awad et al., 2010; Walter et al., 2011; Magrath et al., 2020). Here, EGF is linked to Ewing sarcoma.