Innovations for the development of cancer vaccines are emerging from advances in molecular immunology and cancer biology (1 ). Of these, DNA-based vaccination has become a powerful and potentially versatile method for eliciting an immune response against cancer. One method for DNA immunization involves the delivery of plasmid DNA by particle bombardment. Originally developed for plant hybridization, this approach has proven to be readily transferable to mammalian applications (2 –3 ). Otherwise known as the gene gun, this method allows for the introduction of exogenous “naked” DNA into skin (4 ) (Fig. 1 ).