More recently, talimogene laherparepvec (T-VEC; Amgen, Thousand Oaks, CA, USA), a modified herpes simplex virus (HSV) expressing the immunostimulatory cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF), was evaluated in a randomised phase III trial for the treatment of patients with unresectable metastatic melanoma (ClinicalTrials.gov identifier: NCT00769704) [4]. The gene discussed is CSF2; the disease is metastatic melanoma.