A significantly higher amounts of IL-12 are detected in T-mfIL12-treated tumors than T-mIL12-IRES-treated ones, leading to stronger antitumor immune responses as evidenced by IFNγ measurement, ELISpot assay and immunohistochemistry in the poorly immunogenic, Neuro2a tumor model in HSV-1 sensitive A/J mice. The gene discussed is IFNG; the disease is neoplasm.