Potential molecular targets in neuroblastoma include ALK mutations, p16 deletion and CDK2A mutations; however, targeted therapeutics have not been developed for these factors. We developed Wr-T, a new system for intracellular peptide and protein delivery with a 30-residue sequence that mediates molecule entrapment and intracellular permeability. Wr-T was used to introduce the p16INK4a functional peptide to restore the tumor suppressor function of p16INK4a. Introduction of Wr-T into rats with subcutaneous grafts of neuroblastoma produced an astonishing 75.6% tumor suppression (p<0.0005). Thus, the p16INK4a functional peptide can be introduced in low doses and, because it exists in vivo, it should produce fewer side-effects than standard chemotherapy. We suggest this system could be used for molecular-targeted peptides other than p16INK4a and should be pursued for further development.