title: Expression of epidermal stem cell markers in skin and adnexal malignancies.
abstract: BACKGROUND
  Epidermal stem cells are multipotent cells that maintain the skin epidermis. Potential markers for stem cells have been identified in mammalian skin from mouse experiments; however, it is unclear if stem cells also contribute to tumour formation in human skin.
  
  
  OBJECTIVE
  To investigate the expression of potential stem cell markers, such as leucine-rich repeat-containing G protein-coupled receptor (Lgr) 5, Lgr6, leucine-rich repeats and immunoglobulin-like domain protein 1 (Lrig1) and cytokeratin 15 (CK15) in basal cell carcinomas and tumours of the skin appendages.
  
  
  METHODS
  We tested 45 human basal cell carcinomas (BCCs), including superficial, nodular, adenoid, infiltrating and sclerosing types, and 38 human tumours of skin appendages, including 13 sebaceous adenomas and carcinomas, 20 eccrine sweat gland tumours and five pilomatricomas, for the expression of hair follicle stem cell markers such as Lgr5, Lrig1, CK15, β-catenin and SRY (sex determining region Y)-box 9 (SOX9), and compared these findings with those of healthy age-matched human epidermis.
  
  
  RESULTS
  We detected the expression of stem cell markers in all tumours tested. Regarding Lgr5, Lrig1, CK15 and SOX9, expression seemed to be lower in more aggressive tumour types, such as in the most advanced parts of infiltrating BCC, in sebaceous carcinoma and late-stage porocarcinoma, compared with less aggressive superficial or nodular BCC or early-stage porocarcinoma and sebaceous gland tumours. In aggressive, sclerosing BCC, Lrig1 and Lgr5 were downregulated but CK15, SOX9 and nuclear β-catenin were upregulated.
  
  
  CONCLUSIONS
  Expression of potential stem cell markers of the epidermis and hair follicles was observed in skin tumours of appendages and BCCs. However, during tumour progression, many of these markers seemed to be downregulated.
authors.affiliation: Department of Dermatology and Venereology, Otto-von-Guericke University, Leipziger Strasse, Magdeburg, 39120, Germany. sven.quist@med.ovgu.de.
authors.forename: S R
authors.initials: SR
authors.lastname: Quist
authors.affiliation: Department of Dermatology and Venereology, Otto-von-Guericke University, Leipziger Strasse, Magdeburg, 39120, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Eckardt
authors.affiliation: Department of Dermatology and Venereology, Otto-von-Guericke University, Leipziger Strasse, Magdeburg, 39120, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Kriesche
authors.affiliation: Department of Dermatology and Venereology, Otto-von-Guericke University, Leipziger Strasse, Magdeburg, 39120, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Gollnick
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D002280:Basal Cell Carcinoma / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D004817:Epidermis / Q000378:metabolism; D006201:Hair Diseases / Q000378:metabolism; D018859:Hair Follicle / Q000378:metabolism; D006801:Humans; D053569:Keratin-15 / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D018296:Pilomatrixoma / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000378:metabolism; D012626:Sebaceous Gland Neoplasms / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism*; D013544:Sweat Gland Neoplasms / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology; D051176:beta Catenin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D053569:Keratin-15; C484445:LRIG1 protein, human; D008562:Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D051176:beta Catenin