Cancer vaccines

It has been more than 100 years since the first reported attempts to activa te a patient's immune system to eradicate developing cancers. Although a fe w of the subsequent vaccine studies demonstrated clinically significant tre atment effects, active immunotherapy has not yet become an established canc er treatment modality. Two recent advances have allowed the design of more specific cancer vaccine approaches: improved molecular biology techniques a nd a greater understanding of the mechanisms involved in the activation of T cells. These advances have resulted in improved systemic antitumor immune responses in animal models. Because most tumor antigens recognized by T ce lls are still not known, the tumor cell itself is the best source of immuni zing antigens, For this reason, mast vaccine approaches currently being tes ted in the clinics use whole cancer cells that have been genetically modifi ed to express genes that are now known to be critical mediators of immune s ystem activation. In the future, the molecular definition of tumor-specific antigens that are recognized by activated T cells will allow the developme nt of targeted antigen-specific vaccines for the treatment of patients with cancer. (C) 1999 by American Society of Clinical Oncology.