Cancer immunoprevention: a new approach to intercept cancer early.

Cancer immunoprevention refers to the modulation of the host immune response to control the initiation or development of cancer. The significant role of host immunity in early tumorigenesis has only recently been confirmed, as a better understanding of the mechanisms, molecules and cells involved in tumor immunology have been elucidated over the past two decades. Of utmost importance, preclinical and clinical evidences have demonstrated that early neoplastic cells (transformed cells that initiate cancer formation) express antigens that allow the immune system to distinguish them from normal cells. Furthermore, recognition of the aberrant cell by the immune cells activates a complex interaction of mutual modulation between the immune cells, the tumor and the tumor microenvironment that may result not only in inhibition but also promotion of cancer. The deepening understanding of cancer-related immunologic processes, properties, and components has spawned exploration of more rational, mechanism-based immunologic strategies (using vaccines, antibodies, and immune modulators) for cancer prevention. This introduction to the Cancer Prevention Research immunoprevention series will attempt to review the basics of the immune response modulation as a basis for potential application to cancer immunoprevention strategies with an emphasis on vaccines. Recognizing the fast-paced research in immune response modulation, the series will cover current understandings and future directions of cancer immunoprevention research.