title: Expression of small proline rich proteins in neoplastic and inflammatory skin diseases.
abstract: BACKGROUND
  The formation of the cornified cell envelope (CE) during the late stages of epidermal differentiation is essential for epidermal barrier function and protects the body against environmental attack and water loss. Formation of the CE involves the replacement of the plasma membrane by cross-linkage of precursor proteins such as involucrin, small proline rich proteins (SPRR) and loricrin. In normal epidermis, SPRR1 is restricted to appendages, SPRR2 is also expressed in interfollicular areas, while SPRR3 is completely absent; the latter is most abundant in oral epithelium. This differential expression indicates an important part for SPRRs in specific barrier requirements, and reflects their importance in the biomechanical properties of the CE.
  
  
  OBJECTIVE
  We report here on the expression of SPRR1, SPRR2 and SPRR3 in a wide range of cutaneous neoplastic and inflammatory diseases.
  
  
  METHODS
  We used immunohistochemistry; in addition, Northern blot analysis of malignant tumours was performed.
  
  
  RESULTS
  Increased suprabasal expression of SPRR1 and SPRR2, but no SPRR3 expression, was noted in inflammatory dermatoses with orthokeratotic and parakeratotic squamous differentiation. By contrast, differentiating epidermal tumours such as Bowen's disease, keratoacanthoma and squamous cell carcinoma expressed SPRR3.
  
  
  CONCLUSIONS
  As SPRRs were originally cloned on the basis of their expression in ultraviolet light-irradiated keratinocytes, the expression of SPRR3 in actinic lesions is of interest, and might serve as a diagnostic tool.
authors.affiliation: Department of Dermatology, CHUV/DHURDV, CH-1011 Lausanne, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: De Heller-Milev
authors.forename: M
authors.initials: M
authors.lastname: Huber
authors.forename: R
authors.initials: R
authors.lastname: Panizzon
authors.forename: D
authors.initials: D
authors.lastname: Hohl
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D015152:Blotting, Northern; D018797:Cell Cycle Proteins / Q000378:metabolism; D055233:Cornified Envelope Proline-Rich Proteins; D003872:Dermatitis / Q000378:metabolism*; D020558:GTP Phosphohydrolases; D006801:Humans; D007381:Intermediate Filament Proteins / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism; D008565:Membrane Proteins; D009363:Neoplasm Proteins / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D055232:Proline-Rich Protein Domains; D011506:Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012867:Skin / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D055233:Cornified Envelope Proline-Rich Proteins; D007381:Intermediate Filament Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D010455:Peptides; D011506:Proteins; C096553:SPR3 protein, S cerevisiae; C491986:SPRR2B protein, human; C491987:SPRR2D protein, human; D029701:Saccharomyces cerevisiae Proteins; D020558:GTP Phosphohydrolases