A new era involving the evaluation of recombinant vaccines for colon cancer has begun with the concurrent emergence of insights and technologies in the fields of molecular biology and immunology. These advances include (I) the identification and cloning of an array of genes associated with the neoplastic process, such as oncogenes, suppressor genes, genes encoding oncofetal antigens, and tissue lineage determinants;(2) the development of a variety of viral and bacterial vectors to deliver and present gene products;(3) the identification of numerous T-cell costimulatory molecules and the knowledge of their mode of action;(4) the cloning and analysis of the modes of action of an array of cytokines and other immunomodulatory molecules; and (5) a more sophisticated knowledge of the mode (s) of antigen presentation and T-cell activation.