T-VEC, OrienX010, and many subsequent “next-generation” oncolytic viruses share specific modifications to the HSV-1 backbone, including deletion of ICP34.5 to attenuate neurovirulence and restrict viral replication to tumor cells, deletion of ICP47 to enhance immunogenicity, and engineered expression of human GM-CSF to stimulate dendritic cell response and prime the adaptive immune system for systemic anti-tumor T cell response [34,37,38,39,44,45,51,53]. The gene discussed is CSF2; the disease is neoplasm.