Cancer therapy has entered a new era since the discovery of the oncolytic potential of viruses such as T-VEC, a human herpes simplex virus type 1, which is modified to selectively replicate and secrete human granulocyte–macrophage colony-stimulating factor (GM-CSF) in tumor cells, resulting in activation of the immune response and killing of the infected target [53]. This evidence concerns the gene CSF2 and cancer.