While these studies provide a hypothetical mechanistic background for CXCR4 – PDGFRB interactions in vivo, our data highlight that plerixafor not only affects Ewing sarcoma’s tumor cell – microenvironment interaction but can trigger cellular survival signaling cascades, both possibly amenable to tyrosine kinase co-targeting strategies. The gene discussed is PDGFRB; the disease is Ewing sarcoma.