Pexa-Vec (pexastimogene devacirepvec, JX-594) is an oncolytic vaccinia virus with the thymidine kinase gene inactivated and genetically modified to express human GM-CSF for selective replication in cancer cells, with cell-cycle defects and epidermal growth factor receptor/Ras pathway activation to cause direct oncolysis once infecting cancer cells, plus its GM-CSF expression that also stimulates shutdown of tumor vasculature and antitumor immunity [100]. The gene discussed is CSF2; the disease is neoplasm.