Target molecules in specific immunotherapy against prostate cancer.

Recent advances in molecular biology and tumor immunology have allowed us to identify genes encoding human cancer-related antigens and their peptides that are recognized by cytotoxic T lymphocytes (CTLs). Although these advances have been preceded by studies on melanoma antigens, prostate cancer is another target candidate for specific immunotherapy. Several prostate tissue-specific antigens can be target molecules in specific immunotherapy for prostate cancer. The distribution of prostate tissue-specific antigens is more localized than that of melanoma-related antigens. Prostate-specific antigen (PSA) is available as an evaluation indicator of clinical course. In addition, epithelial cancer-related antigens are also applicable for prostate cancer patients. These lines of evidence suggest that prostate cancer is the best candidate for specific immunotherapy among the various types of epithelial cancers. A number of epitope peptides which have the potential to generate prostate cancer-reactive CTLs have been identified to date, and clinical trials targeting these molecules have been conducted. In this article, we review prostate cancer-related antigens and their epitope peptides, which have potential for use in the immunotherapy of prostate cancer patients, and we introduce the current status of clinical trials of specific immunotherapy targeting these molecules.