title: Ets-1 immunohistochemical expression in non-melanoma skin carcinoma.
abstract: BACKGROUND
  Ets-1 oncoprotein is a transcription factor known to regulate the expression of numerous genes important in extracellular matrix remodeling and angiogenesis. Up-regulation of Ets-1 has been shown to be important in a variety of human malignancies and to correlate with prognosis. To our knowledge, this oncoprotein has not been examined in non-melanoma skin carcinomas.
  
  
  METHODS
  A series of 26 primary cutaneous skin lesions with patient records were independently examined for diagnosis confirmation and immunohistochemical expression by two dermatopathologists. The immunohistochemical expression for Ets-1 (Novocastra, Newcastle Upon Tyne, England, UK) was scored by an average of the mean labeling intensity (MLI), where no nuclear staining = 0, weak nuclear staining = 1, moderate nuclear staining = 2, and strong nuclear staining = 3.
  
  
  RESULTS
  All basal cell carcinoma (BCC) and Merkel cell carcinoma (MCC) cases exhibited negative nuclear staining, for an average MLI of 0. Keratoacanthomas, squamous cell carcinoma in situ (SIS), and well-differentiated squamous cell carcinomas (SCCs) exhibited negative to weak nuclear staining, for an average MLI of 0.4 +/- 0.3. Moderately differentiated SCCs exhibited moderate nuclear staining, for an average MLI of 1.8 +/- 0.6. Poorly differentiated SCCs and metastatic SCCs exhibited very strong nuclear staining, with an average MLI of 2.8 +/- 0.2.
  
  
  CONCLUSIONS
  Ets-1 is not expressed in cutaneous BCC or MCC and is weakly expressed in SIS and forms of well-differentiated SCC. Although the intensity of Ets-1 immunostaining distinguished between well-differentiated and poorly differentiated SCC (p < 0.0001), it failed to discriminate between in situ and well-differentiated SCCs. The preliminary data suggests Ets-1 may be important in the pathogenesis of invasive SCC.
authors.affiliation: Department of Pathology, University of South Florida College of Medicine, Tampa, FL, USA.
authors.forename: Connie A
authors.initials: CA
authors.lastname: Keehn
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Smoller
authors.forename: Michael B
authors.initials: MB
authors.lastname: Morgan
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism* / Q000556:secondary; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D050783:Proto-Oncogene Proteins c-ets; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D014157:Transcription Factors / Q000096:biosynthesis*; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; C494041:ETS1 protein, human; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors