title: Tumor-associated antigen profiling in breast and ovarian cancer: mRNA, protein or T cell recognition?
abstract: OBJECTIVE
  The absence of tumor-associated antigens (TAA) which might elicit an immune response is one reason for the disappointing results of therapeutical vaccines in cancer patients. Moreover, impaired expression of MHC class-I and components involved in antigen processing, such as TAP-1, -2, LMP-2, -7, and MECL-1, may lead to tumor escape from immune recognition. Expression profiling of TAA is one approach towards the design of well-defined and individualized anti-tumor vaccines.
  
  
  METHODS
  Quantitative polymerase chain reaction (qRT-PCR) is the method of choice to characterize immunologically relevant properties of individual tumors. However, the application of qRT-PCR as a surrogate parameter for the expression of TAAs depends upon the assumption that the level of an mRNA species correlates with the cellular level of the protein it encodes. Therefore, we additionally analyzed TAA expression by immunofluorescence and T cell recognition.
  
  
  RESULTS
  In the present study we were unable to confirm that impaired TAP-1 or -2 (transporter associated with antigen processing) expression characterized at the mRNA level is an appropriate surrogate parameter for down-regulated MHC class-I expression in breast cancer. In addition, we analyzed the expression pattern of TAAs in breast and ovarian cancer cell lines. Besides the well-known over-expression of HER-2/neu, CEA, and MUC-1, multiple antigens of the MAGE-family were frequently co-expressed. We investigated whether detection of TAAs by qRT-PCR correlates with monoclonal antibody staining, and which method could predict T cell recognition. We demonstrated a correlation between tumor cell lysis by HLA-A*0201-restricted, MUC-1-specific CTL and threshold levels of MUC-1-specific mRNA.
  
  
  CONCLUSIONS
  MUC-1 is an example that TAA profiling by RT-PCR and flow cytometry can fail to correlate with each other and are of limited value in the prediction of T cell recognition.
authors.affiliation: Department of Gynecology and Obstetrics, University of Tübingen, Calwerstrasse 7, 72076, Tübingen, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Kayser
authors.forename: Iris
authors.initials: I
authors.lastname: Watermann
authors.forename: Christine
authors.initials: C
authors.lastname: Rentzsch
authors.forename: Toni
authors.initials: T
authors.lastname: Weinschenk
authors.forename: Diethelm
authors.initials: D
authors.lastname: Wallwiener
authors.forename: Brigitte
authors.initials: B
authors.lastname: Gückel
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000951:Antigens, Neoplasm / Q000032:analysis*; D001483:Base Sequence; D001943:Breast Neoplasms / Q000276:immunology*; D002277:Carcinoma / Q000276:immunology* / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D016130:Immunophenotyping; D009363:Neoplasm Proteins / Q000032:analysis*; D010051:Ovarian Neoplasms / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D018528:ATP-Binding Cassette Transporters; D000951:Antigens, Neoplasm; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D009363:Neoplasm Proteins; D012333:RNA, Messenger; C477327:transporter associated with antigen processing (TAP)