Adenoviral delivery of genes for cytokines and other immunomodulators is widely used in cancer therapy in the animal tumor models as well as in patients [137, [175] [176] [177] [178] . The T cells play an important role not only in defense against the pathogens, but also in antitumor immunity and inhibition of the tumor growth. Interleukin-12 inhibits the angiogenesis and induces a potent antitumoral immune response by stimulation of IFNγ secretion. Therefore, IL-12 is a promising candidate for cancer gene therapy [179] [180] [181] [182] [183] . Strategy based on recombinant adenoviruses expressing IL-12 demonstrated antitumor effect in the murine models with transplantable HCC [184, 185] and was also evaluated in woodchucks [168] .