Furthermore, it was important for us to demonstrate that efficacy in the tumour models was dependent upon the expressed gene product, and not stimulation through activation of TLR9 innate immune responses by CpG sites, as a previously published by Rodrigo-Garzón et al. of a l-PEI/plasmid nanoparticle expressing IL-12 in a Lewis lung carcinoma model33. Here, TLR9 is linked to neoplasm.