Regarding the versatility of the methodology, non-viral systems involving IL-12 GET, CSPG4 GET, and the suicide gene system plus IFN-β (combined with cytokine-enhanced vaccines), have shown encouraging results in different types of canine tumors: mastocytoma and melanoma for the IL-12 gene [52,54], melanoma and osteosarcoma for the CSPG4 gene [31,33], and melanoma and mammary carcinoma for the suicide gene system [67,68]. This evidence concerns the gene CSPG4 and osteosarcoma.