Fig. 1From: Emerging therapies for small cell lung cancerMechanisms of action for targeted agents. VEGFR, vascular endothelial growth factor receptor; PDGFR, platelet-derived growth factor receptor; FGFR, fibroblast growth factor receptor; DLL3, delta-like protein 3; PARP, poly (ADP-ribose) polymerase; PDL-1, programmed death ligand 1; PD1, programmed death 1; CTLA-4, cytotoxic T lymphocyte antigen-4Back to article page