title: Phenotypic characterization of oral mucosa: what is normal?
abstract: BACKGROUND
  Knowledge of the phenotypic pattern of oral squamous epithelium is important in the histopathologic evaluation of lesions including cancer. The literature on normal epithelium is controversial as the phenotype has not been evaluated in samples from completely healthy tissue donors without a history of tobacco and alcohol exposure.
  
  
  METHODS
  In this study, we evaluated normal upper lip fornix and gingival mucosa from carefully selected young healthy donors without a history of smoking and alcohol exposure, and keratin types 8, 10, 14, and 17, filaggrin, and Ki67 were investigated in these donors. The results were compared with profile of epithelium from leukoplakia.
  
  
  RESULTS
  The results demonstrated that the phenotypic patterns of gingiva and upper lip fornix mucosa were different. Surprisingly, a high proportion of gingival samples exhibited keratin 8 and a suprabasal signal for keratin 14. These patterns were compared with that of human oral leukoplakia, and some phenotypic similarities were noted.
  
  
  CONCLUSIONS
  These results demonstrated oral epithelium phenotypic plasticity based on functional requirements of the microenvironment, which can be used in diagnosis.
authors.affiliation: Department of Dental Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Valach
authors.affiliation: Department of Dental Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
authors.forename: René
authors.initials: R
authors.lastname: Foltán
authors.affiliation: Department of Dental Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Vlk
authors.affiliation: Institute of Anatomy, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.|Department of Biomedical Research, East-Slovak Institute of Cardiovascular Diseases, Košice, Slovakia.|BIOCEV, 1st Faculty of Medicine, Charles University, Vestec, Czech Republic.
authors.forename: Pavol
authors.initials: P
authors.lastname: Szabo
authors.affiliation: Institute of Anatomy, 1st Faculty of Medicine, Charles University, Prague, Czech Republic.|BIOCEV, 1st Faculty of Medicine, Charles University, Vestec, Czech Republic.
authors.forename: Karel
authors.identifier: http://orcid.org/0000-0002-7878-8403
authors.initials: K
authors.lastname: Smetana
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D000091344:Filaggrin Proteins; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000033:anatomy & histology* / Q000473:pathology; D010641:Phenotype; D055815:Young Adult
keywords: gingiva; keratin; leukoplakia; merkel cell; microenvironment