“…This would circumvent several problems such as systemic toxicity, rapid degradation and the short half-life associated with systemic delivery of various recombinant cytokines. 16 IL-12 is an immune regulatory cytokine, which plays multiple roles in altering the host-tumor relationship, such as: (1) enhancement of the cellular immune mechanism to favor activation and proliferation of CD4 + helper T cells and CD8 + cytotoxic T cells leading to potent Th1 type immune response; (2) recruitment of cytotoxic NK and NKT cells to directly participate in early stages of tumor killing; and (3) up-regulation of endogenous IFN-␥ and TNF-␣, as well as NO to suppress tumor progression, metastasis and angiogenesis. 17 In the present study, we investigated the role of IL-12 gene delivery with a broader perspective, looking into its role in simultaneous induction of various anti-tumoral cytokines, cytotoxic NO, as well as its role in recruitment of various immune cells, which form a part of innate and adaptive immunity, resulting in anti-tumor activity.…”