title: Advances in the understanding of malignant transformation of keratinocytes: an immunohistochemical study.
abstract: OBJECTIVE
  We set out to investigate the interactions between malignant transformation of keratinocytes, presence of oncoproteins and immunosurveillance in squamous cell carcinoma (SCC) and in a preneoplastic lesion, actinic keratosis (AK).
  
  
  METHODS
  Samples of SCC, AK and normal skin (NS) were subjected to quantitative analysis using the following antibodies: anti-p53, Ki67, OKT6, OK-DR, B7/BB1, anti-CD54, anti-CD11, OKT3, OKT4, OKT8; positivity for ras-p21, EGFr and bcl-2 was evaluated by semiquantitative analysis.
  
  
  RESULTS
  Oncoprotein alterations and increased keratinocyte proliferative activity were observed both in AK and SCC. The number of Langerhans cells (CD1a+ cells) was similar in the two lesions but lower in SCC compared to AK. The proportion of CD1a(+)-B7/BB1+ cells was slightly higher in AK and SCC than in NS. The Langerhans cells expressed the HLA-DR antigen in all groups. Values were highest in AK and NS, and quite low in SCC. Cytotoxic T lymphocytes were more numerous in SCC than in AK and NS. Interestingly, the total CD4/CD8 ratio was much lower in SCC than in AK and NS, which indicates an increase in the CD8+ subpopulation in samples of SCC. In the epithelia of SCC samples there were a considerable number of B7/BB1+ keratinocytes.
  
  
  CONCLUSIONS
  We suggest that alterations in the immunodefence mechanisms have an important role in the transformation of AK into SCC, and that these changes affect not only lymphocytes, but also professional (i.e., Langerhans cells) and non-professional (i.e., keratinocytes) antigen presenting cells.
authors.affiliation: Department of Research, I.N.R.C.A., Ancona, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Tucci
authors.forename: A
authors.initials: A
authors.lastname: Offidani
authors.forename: G
authors.initials: G
authors.lastname: Lucarini
authors.forename: L
authors.initials: L
authors.lastname: Simonelli
authors.forename: S
authors.initials: S
authors.lastname: Amati
authors.forename: A
authors.initials: A
authors.lastname: Cellini
authors.forename: G
authors.initials: G
authors.lastname: Biagini
authors.forename: G
authors.initials: G
authors.lastname: Ricotti
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001707:Biopsy, Needle; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000737:chemistry* / Q000276:immunology; D002471:Cell Transformation, Neoplastic / Q000737:chemistry* / Q000276:immunology; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000032:analysis; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D015603:Keratinocytes / Q000737:chemistry* / Q000276:immunology; D007642:Keratosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015513:Oncogene Proteins / Q000032:analysis; D011230:Precancerous Conditions / Q000737:chemistry* / Q000276:immunology; D012878:Skin Neoplasms / Q000737:chemistry* / Q000276:immunology
chemical_list: D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D006684:HLA-DR Antigens; D015513:Oncogene Proteins; D018799:Intercellular Adhesion Molecule-1; D004815:Epidermal Growth Factor