Discovery and development of therapeutic cancer vaccines.

Over the past century, various efforts have been made to induce the rejection of cancerous tissues by the stimulation of an immune reaction, using both non-specific and antigen-specific strategies. Non-specific approaches attempt to augment an immune response in and around the tumor by injecting immune stimulating substances, for example, bacterial extracts, cytokines or gene therapy agents. Antigen-specific approaches use either the tumor cells themselves as a source of antigens or incorporate identified tumor-associated antigens into vaccines. This review describes antigen-specific therapeutic cancer vaccines that are currently in development.