New concepts in tumor antigens: their significance in future immunotherapies for tumors.

The identification and molecular characterization of self-antigens expressed by human malignancies that are capable of elicitation of anti-tumor immune responses in patients have been an active field in tumor immunology. More than 2,000 tumor antigens have been identified, and most of these antigens are self-antigens. These significant progresses have led to the renaissance of tumor immunology and studies on anti-tumor immunotherapy. However, despite of the progress in the identification of self-tumor antigens, current antigen-specific immunotherapies for tumors are far less satisfied than expected, which reflects the urgent need to improve our understanding on self-tumor antigens. In order to develop more effective antigen specific anti-tumor immunotherapies and to monitor the responses to these immunotherapies in patients with tumors, many important fundamental questions need to be addressed. We propose for the first time that the studies in addressing the characteristics of self-tumor antigens and autoantigens are grouped as a new subject termed "antigenology". In this brief review, we would outline the progress in the identification of tumor antigens in solid tumors and hematologic malignancies, and overview the new concepts and principles of antigenology and their significance for future immunotherapies to these malignancies.