title: Signal transducer and activator of transcription-3 expression and activation is dysregulated in actinic cheilitis.
abstract: BACKGROUND
  The present study evaluates the signal transducer and activator of transcription-3 (STAT-3) expression and activation in actinic cheilitis (AC) and the relationship of this protein with the degree of epithelial dysplasia.
  
  
  METHODS
  Twenty-five cases of AC were analyzed. Normal lip mucosa was used as a control group. AC lesions were graded as mild, moderate and severe dysplasias. Immunohistochemistry for STAT-3 and phospho-STAT-3 (STAT-3P) was performed using the biotin-streptavidin-peroxidase method, and the sections were evaluated by three blinded examiners.
  
  
  RESULTS
  In normal lip mucosa, only cytoplasmic expression of STAT-3 was observed in the basal and parabasal layers. In AC, STAT-3 was expressed in the cell cytoplasm of the epithelial layers, except in the superficial layer. Nuclear expression of STAT-3 in occasional basal and parabasal cells was seen in moderate and severe dysplasias. In normal lip mucosa, nuclear expression of STAT-3P was found throughout the epithelium, except in the superficial layers, and it was more intense in the deeper layers. In AC, STAT-3P was also expressed in all layers, except for the superficial layer. However, in moderate and severe dysplasias, some epithelial cells exhibited loss of STAT-3P expression.
  
  
  CONCLUSIONS
  In AC, STAT-3 expression depends on the degree of dysplasia, and STAT-3 activation is dysregulated compared with normal tissue.
authors.affiliation: Department of Microbiology and Immunology, São Leopoldo Mandic Dental Research Center, Rua Abolição, 1827 Ponte Preta, Campinas, São Paulo, CEP 13045-610 Brazil.
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Cury
authors.forename: Cristiane
authors.initials: C
authors.lastname: Furuse
authors.forename: Ney S
authors.initials: NS
authors.lastname: de Araújo
authors.forename: Vera C
authors.initials: VC
authors.lastname: de Araújo
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D002613:Cheilitis / Q000378:metabolism* / Q000473:pathology*; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008046:Lip / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010787:Photosensitivity Disorders / Q000378:metabolism* / Q000473:pathology*; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D050796:STAT3 Transcription Factor / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human