title: Ber-EP4-positive phenotype differentiates actinic keratosis from superficial basal cell carcinoma.
abstract: BACKGROUND
  Well-defined histopathologic criteria exist to distinguish actinic keratosis (AK) from superficial basal cell carcinoma (BCC). A similar morphology of downwardly budding dysplastic keratinocytes may occur in both entities, creating potential for errors in diagnosis. A marker that could reliably distinguish these two lesions would overcome this difficulty in diagnosis.
  
  
  OBJECTIVE
  To investigate whether Ber-EP4 staining is useful in distinguishing AK from superficial BCC, and to determine whether AK exhibits a cellular phenotype that is more consistent with BCC or squamous cell carcinoma (SCC).
  
  
  METHODS
  We subjected tissue sections from superficial BCC, AK, and squamous intraepithelial neoplasia (SIN) demonstrating epidermal budding to immunohistochemical staining with monoclonal antibody Ber-EP4.
  
  
  RESULTS
  Abnormal keratinocytes in all specimens of superficial BCC (5 of 5) were Ber-EP4 positive; all AK (10 of 10) and SIN (8 of 8) were Ber-EP4 negative.
  
  
  CONCLUSIONS
  Ber-EP4 staining reliably distinguishes AK from superficial BCC. The lack of Ber-EP4 staining of AK supports the currently accepted pathogenetic dogma that SIN and SCC arise from AK, but BCC does not.
authors.affiliation: Department of Dermatology, University of Minnesota, Minneapolis, Minnesota 55455-0392, USA. topex001@tc.umn.edu
authors.forename: W D
authors.initials: WD
authors.lastname: Tope
authors.forename: M
authors.initials: M
authors.lastname: Nowfar-Rad
authors.forename: D A
authors.initials: DA
authors.lastname: Kist
mesh_terms: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002280:Basal Cell Carcinoma / Q000175:diagnosis*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D010641:Phenotype; D011230:Precancerous Conditions / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012878:Skin Neoplasms / Q000175:diagnosis*; D000951:Antigens, Neoplasm
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D014408:Biomarkers, Tumor; C115012:human epithelial antigen-125; D000951:Antigens, Neoplasm