title: c-Jun, pc-Jun, and p27 are differently expressed in oral leukoplakias in smokers and never-smokers.
abstract: OBJECTIVE
  Oral cancer may be preceded by potentially malignant lesions, and smoking is a risk factor. Oral leukoplakia (OL), which is the most common among these lesions, is defined by the World Health Organization as "a white plaque of questionable risk having excluded known diseases or disorders that carry no increased risk for cancer." Thus, OL is a clinical diagnosis used to designate oral white lesions, which are histologically represented by hyperkeratosis associated or not associated with epithelial dysplasia. It is known that c-Jun and pc-Jun have a role in cell proliferation and that p27 is decreased during carcinogenesis; thus, the aim of this study was to investigate whether these proteins are differently expressed in OL in smokers and never-smokers.
  
  
  METHODS
  Seventy-three cases diagnosed as OL were selected and divided into four groups according to the presence or absence of dysplasia and patients' smoking status (smokers: 39 cases, 24 dysplastic; never-smokers: 34 cases, 20 dysplastic). The immunoexpressions of c-Jun, pc-Jun, and p27 were evaluated.
  
  
  RESULTS
  A significant correlation between smoking condition and the percentages of c-Jun (P = .0356) and pc-Jun (P = .0216) was found and was more intense in cases that underwent malignant transformation (6/47).
  
  
  CONCLUSIONS
  Smoking habits may be linked to the expression of proteins directly associated with cell cycle progression.
authors.affiliation: Oral Pathology Department, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Joelma Sousa
authors.initials: JS
authors.lastname: Lima
authors.affiliation: General Pathology Department, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Correa
authors.affiliation: Oral Pathology Department, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Maria Fátima Guarizo
authors.initials: MF
authors.lastname: Klingbeil
authors.affiliation: Oral Pathology Department, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil; Research fellow of CNPq, Oral Pathology Department, School of Dentistry, University of São Paulo, SP, Brazil. Electronic address: scmsouza@usp.br.
authors.forename: Suzana C Orsini Machado
authors.initials: SC
authors.lastname: de Sousa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007972:Leukoplakia, Oral / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*
chemical_list: D016755:Proto-Oncogene Proteins c-jun; D050760:Cyclin-Dependent Kinase Inhibitor p27