title: Expression of apoptotic and cell proliferation regulatory proteins in actinic cheilitis.
abstract: BACKGROUND
  Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation. The apoptotic proteins p53, bax, bcl-2, and the proliferation marker Ki-67, are known to play an important role in UV-exposed skin and carcinomas, therefore, these markers were assessed in AC and compared with normal lip and oral mucosa.
  
  
  METHODS
  AC (n = 13), normal lip (n = 7) and oral mucosa (n = 6) biopsies were stained immunohistochemically for p53, bax, bcl-2 and Ki-67, to determine their expression and distribution.
  
  
  RESULTS
  p53 was over-expressed in AC as compared with normal lip and oral mucosa (P < 0.003). Although bcl-2 expression was higher in AC than in oral mucosa (P < 0.002), it was significantly reduced as compared with normal lip (P < 0.04). Bax expression remained unchanged, and Ki-67 was significantly increased in AC and normal lip as compared with oral mucosa (P < 0.05).
  
  
  CONCLUSIONS
  The results suggest that DNA-damaged cells by UV radiation in AC are eliminated by apoptosis.
authors.affiliation: Department of Oral Pathology, College of Dentistry, Universidad de Concepción, Chile. almartin@udec.cl
authors.forename: A
authors.initials: A
authors.lastname: Martínez
authors.forename: U
authors.initials: U
authors.lastname: Brethauer
authors.forename: I G
authors.initials: IG
authors.lastname: Rojas
authors.forename: M
authors.initials: M
authors.lastname: Spencer
authors.forename: F
authors.initials: F
authors.lastname: Mucientes
authors.forename: J
authors.initials: J
authors.lastname: Borlando
authors.forename: M I
authors.initials: MI
authors.lastname: Rudolph
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D017209:Apoptosis; D049109:Cell Proliferation; D002613:Cheilitis / Q000209:etiology / Q000378:metabolism*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000096:biosynthesis*; D008046:Lip / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D018709:Statistics, Nonparametric; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D014466:Ultraviolet Rays / Q000009:adverse effects; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein