Costaining for GFP and the pericyte/vSMC markers, desmin, alpha smooth muscle actin (α-SMA), and platelet, derived growth factor receptor beta (PDGFR-β), demonstrated that many of the GFP+ BM-derived cells also expressed pericyte/vSMC markers, indicating that BM cells differentiate into pericyte/vSMC in Ewing's sarcoma in vivo [16]. The gene discussed is PDGFRB; the disease is Ewing sarcoma.