CSF2 and neoplasm: RP-1 (by Replimmune Group Inc. Woburn, MA, USA) is a derivative of a wild-type HSV1 isolate containing deletions of γ34.5 and ICP47 and expresses GM-CSF and GALV-GP-R--a fusogenic membrane glycoprotein from gibbon ape leukemia virus that was shown to increase tumor-cell killing potential and immunogenic effects [58].