Cancer Vaccines: The Role of Tumor Burden in Tipping the Scale Toward Vaccine Efficacy

Cancer vaccines have significant theoretical therapeutic advantages over more standard methods of cancer treatment. If a robust cellular immune response could be elicited, then immunologic memory could be long lasting, eradicatingcancerattimesquitedistantfrominitialtherapy.Tcells potentiallycanmigratetotumorsites,leavethevasculature, and invade tissues eradicating deep-seated disease at any metastatic site. Furthermore, T cells are extremely specific in their attack, as opposed to the generalized toxicities seen with some chemotherapies. Finally, as long as there is antigen available for T-cell recognition, T cells have the potential to continue to respond until disease is eradicated. In this issue of the Journal of Clinical Oncology, investigators fromWalterReedArmyMedicalCenter(Washington,DC) and the M.D. Anderson Cancer Center (Houston, TX) present data from a trial in which breast cancer patients were immunized with a vaccine targeting the HER-2/neu oncogenic protein to prevent disease relapse. 1