title: Expression of laminin-5 γ2 chain in cutaneous pseudocarcinomatous hyperplasia.
abstract: BACKGROUND
  Since the use of laminin-5 as a marker of invasiveness has been proposed by several authors, our objective was to compare the expression of this protein in pseudocarcinomatous hyperplasia and squamous cell carcinoma (SCC).
  
  
  METHODS
  Sixty-four paraffin-embedded skin biopsy samples with diagnosis of epidermal hyperplasia (non-pseudocarcinomatous), pseudocarcinomatous hyperplasia, actinic keratosis/carcinoma in situ, microinvasive and frankly invasive SCC were obtained for immunohistochemical study.
  
  
  RESULTS
  Adjacent normal epithelium and epidermal hyperplasia (non-pseudocarcinomatous) showed no staining. In pseudocarcinomatous hyperplasia, laminin-5 was positive, at least focally, in 14 of 16 (87.5%) samples and was concentrated in peripheral cells of elongated rete pegs and in migrating cells in dermis. In samples of microinvasive carcinoma (n = 7), the expression was observed in all cases and was concentrated in the leading edge of the tumor. All cases (n = 21) of frankly invasive SCC showed cells expressing laminin-5, at least focally. Well-differentiated areas of the tumor presented a pattern of expression in peripheral cells of tumor nests while a diffuse pattern of expression was observed in less differentiated areas.
  
  
  CONCLUSIONS
  We showed that cytoplasmic laminin-5 expression should not be used as a criterion of malignancy and is not useful in distinguishing pseudocarcinomatous hyperplasia from microinvasive and well-differentiated SCC.
authors.affiliation: Department of Pathology, University Hospital of Brasília, Brasília, Brazil.
authors.forename: Aline M
authors.initials: AM
authors.lastname: Dos Santos
authors.forename: Fabiana P
authors.initials: FP
authors.lastname: Carneiro
authors.forename: Amadeu J R
authors.initials: AJ
authors.lastname: Queiroz
authors.forename: Emanuel A M
authors.initials: EA
authors.lastname: Damasceno
authors.forename: Tércia M M L
authors.initials: TM
authors.lastname: de Castro
authors.forename: Rivadávio F B
authors.initials: RF
authors.lastname: de Amorim
authors.forename: Gustavo H S
authors.initials: GH
authors.lastname: Takano
authors.forename: Maria I M B
authors.initials: MI
authors.lastname: Junqueira
authors.forename: Albino V
authors.initials: AV
authors.lastname: de Magalhães
mesh_terms: D002278:Carcinoma in Situ / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia / Q000378:metabolism / Q000473:pathology; D055623:Keratosis, Actinic / Q000378:metabolism / Q000473:pathology; D007797:Laminin / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: C400567:LAMC2 protein, human; D007797:Laminin