Regarding the application of FMGs as an independent monotherapy technique, Galanis et al. [35] showed that Measles virus (MV) fusion (F) and hemagglutinin (H) proteins (MV-F and MV-H) and a recombinant form of the retroviral envelope protein of the gibbon ape leukemia virus (GALV.fus) are able to efficiently be employed in glioma gene therapy. The gene discussed is ERVW-1; the disease is glioma.