The results from this study suggest that SFV-delivered vdIFN-γ is as efficient as rIFN-γ in rendering macrophages tumoricidal in vitro, which along with our finding that macrophages but not cancer cells are resistant to SFV infection encourages a possible application of SFV-Ifng vector for activation of tumor-associated macrophages toward tumor-suppressive M1 phenotype in further studies in vivo. The gene discussed is IFNG; the disease is cancer.