Most oncolytic vectors used today are administered intratumorally [77], owing to barriers which prevent systemic targeting, including dilution of the virus in the bloodstream, neutralization by anti-viral antibodies and complement proteins, virus particle sequestration in liver Kupffer cells and splenic macrophages, and the limited permeability of tumor neovessels [78,79]. The gene discussed is VTN; the disease is neoplasm.