Our previous studies demonstrated that VGF and O1-deleted oncolytic VVs elicited potent antitumor effects via systemic antitumor activity rather than local viral oncolytic activity in syngeneic tumor mouse models using melanoma, colon, and lung carcinomas, and its antitumor effects were enhanced by arming VV with the expression of IL-12 and IL-7 [51] or induction of cell-cell fusion [52]. This evidence concerns the gene IL7 and melanoma.