PDGFRA and neoplasm: The inhibitory role of NT21MP on tumor resistance and the expression of CXCR4 and PDGFRα also demonstrated a correlation between the decreased expression CXCR4 and PDGFRα and the inhibition of tumor resistance in vitro and vivo. The blockade of PDGFR, a key mediator of CXCR4 signaling, similarly reversed EMT markers and cell invasion.