title: Cancer/testis antigen MAGE-A4 expression pattern differs in epithelial skin tumors of organ-transplant recipients and immunocompetent patients.
abstract: BACKGROUND
  Lifetime risk for squamous cell carcinoma (SCC) of the skin is 1:30. Risk in organ-transplant recipients (OTR) is increased over 60-fold through long-term drug-induced immunosuppression. MAGE family-derived peptides are cancer/testis antigens recognized by specific CD8(+) T cells and employed for immunotherapy. We were interested in the frequency and distribution of MAGE-A4 in epithelial skin tumors of OTR and immunocompetent patients.
  
  
  METHODS
  mAb 57B predominantly recognizing MAGE-A4 was used to stain 119 formalin-fixed, paraffin-embedded epithelial skin tumors (actinic keratosis, bowenoid actinic keratosis, Bowen's disease, and SCC; n = 17, 25, 61, 16, respectively) in immunocompetent patients (n = 84) and OTR (n = 35).
  
  
  RESULTS
  All four epithelial skin tumors showed comparable immunoreactivity ranging from (25-71%, p = 0.361). Scattered immunoexpression pattern was more frequent in OTR (p = 0.025). SCC showed polarized immunoreactivity basally (p = 0.002).
  
  
  CONCLUSIONS
  MAGE-A4 was expressed in a large part of epithelial skin tumors with predominantly scattered immunoexpression pattern in OTR. The difference in immunoexpression pattern for immune status was limited, suggesting important non-immunosuppressor-mediated mechanisms for increased skin carcinogenesis in OTR. mAb 57B may be a helpful tool for immunohistochemistry and micrographic surgery using formalin-fixed paraffin-embedded tissue.
authors.affiliation: Department of Dermatology, University Hospital Zürich, Zürich, Switzerland.
authors.forename: Beda
authors.initials: B
authors.lastname: Muehleisen
authors.forename: Leo
authors.initials: L
authors.lastname: Schaerer
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dummer
authors.forename: Günter
authors.initials: G
authors.lastname: Burg
authors.forename: Günther F L
authors.initials: GF
authors.lastname: Hofbauer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000378:metabolism*; D001913:Bowen's Disease / Q000378:metabolism* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007121:Immunocompetence; D007150:Immunohistochemistry; D007165:Immunosuppression Therapy; D007642:Keratosis / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D016377:Organ Transplantation; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D014018:Tissue Distribution
chemical_list: D000951:Antigens, Neoplasm; C095204:MAGEA4 protein, human; D009363:Neoplasm Proteins