title: The functioning antigens: beyond just as the  immunological targets.
abstract: Antigenic peptides derived from tumor-associated antigens (TAAs) facilitate peptide cancer vaccine therapies. With the recent progress in cancer immunity research, huge amounts of antigenic peptides have already been reported. Clinical trials using such peptides are underway now all over the world. Some reports have shown the efficacy of peptide vaccine therapies. However, others ended with unfavorable results, suggesting fundamental underlying problems. One major mechanism that negates the peptide vaccine therapy is tumor escape from immunological systems caused by loss of antigens. TAAs that are used in cancer vaccine therapies may be divided into two major groups: functioning antigens and nonfunctioning antigens. A 'functioning antigen' could be defined as a TAA that is essential for tumor growth, is expressed in several kinds of malignancies and shows homogenous expression in cancerous tissues. It is not difficult to imagine that antigen loss will occur easily with non-functioning antigens as a target of cancer vaccine therapy. Thus, it is essential to use functioning antigens for successful cancer vaccine therapy. In this review, we discuss the functioning antigens and their categorization in detail.
authors.affiliation: Department of Pathology, Sapporo Medical University School of Medicine, South-1 West 17, Chuo-ko, Sapporo, 060-8556 Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirohashi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Torigoe
authors.forename: Satoko
authors.initials: S
authors.lastname: Inoda
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kobayasi
authors.forename: Munehide
authors.initials: M
authors.lastname: Nakatsugawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Mori
authors.forename: Isao
authors.initials: I
authors.lastname: Hara
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Sato
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D017209:Apoptosis; D019496:Cancer Vaccines / Q000276:immunology; D006801:Humans; D007167:Immunotherapy; D009369:Neoplasms / Q000098:blood supply / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D009389:Neovascularization, Pathologic / Q000188:drug therapy
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines