A recent study using a hybrid vector expressing an adeno-associated virus and a single-stranded M13 phage (AAVP) displaying a double-cyclic RGD4C motif ligand (which targets alpha V integrin receptors expressed on the surface of tumor vascular endothelium) with the gene sequence for the cytotoxic protein tumor necrosis factor (RGD4C-AAVP-TNF), demonstrated tumor killing when systemically delivered over 3 consecutive doses in an intracranial orthotopic xenograft mouse model of U87MG human glioma (Staquicini et al., 2020). Here, TNF is linked to glioma.