Vaccines are one of the main arms of preventive medicine. Recently a large series of experiments with cancer-prone genetically engineered mice have shown that preventive vaccines are also extremely efficacious inhibitors of the progression of carcinogenesis. Early vaccination affords significant and persistent protection, whereas its efficacy fades when neoplastic lesions become more advanced. Our current attempts to use combination strategies and technological advances to make vaccines effective in cancer prevention able to cure more advanced stages of cancer lesions are based on the temporary and systemic T(reg) removal, the preparation of new bimodular plasmids for DNA vaccination, and the search for fresh target oncoantigens.