Recent advances in genetic engineering of viruses have improved their therapeutic potential, and in 2015 the Food and Drug Administration approved the use of the first oncolytic virus, talimogene laherparepvec (T-VEC), a replication-competent herpes simplex virus 1 (HSV-1) recombinant encoding granulocyte-macrophage colony-stimulating factor (GM-CSF), for the local treatment of melanoma metastases.21 This evidence concerns the gene CSF2 and melanoma.