title: Reduced P53 Staining in Actinic Keratosis is Associated with Squamous Cell Carcinoma: A Preliminary Study.
abstract: BACKGROUND
  Actinic keratosis (AK) is a cutaneous neoplasm caused by prolonged sun exposure, and may progress into squamous cell carcinoma (SCC). The p53 gene plays a central role in the development of SCC, and mutations in this gene are found in 90% of SCC and up to 100% of AK cases.
  
  
  OBJECTIVE
  To identify AK cases that are highly susceptible to developing SCC.
  
  
  METHODS
  Fifty-six AK cases were classified into two groups: AK adjacent to "normal" skin and AK adjacent to SCC. The groups were compared based on epithelial atypia, inflammation, solar elastosis, histopathological AK classification and p53 protein expression.
  
  
  RESULTS
  Of the 56 AK cases analyzed, 23% were associated with SCC. The types of AK observed were classified as follows: common, hypertrophic, atrophic, acantholytic, pigmented and bowenoid. SCC was associated with common and hypertrophic AK, and p53 staining was observed in 78% of AK cases. The mean difference in p53 immunopositivity between common AK cases associated with SCC (17%) and not associated with SCC (45.4%) was significant (p=0.011).
  
  
  CONCLUSIONS
  Hypertrophic and common AK are associated with SCC, and the low percentage of p53 immunopositivity in the common type indicates a greater probability of developing into SCC.
authors.affiliation: Department of Dermatology, Federal University of São Paulo- SP, Brazil.
authors.forename: Pimentel Dr
authors.initials: PD
authors.lastname: Neto
authors.forename: Mma
authors.initials: M
authors.lastname: Alchorne
authors.forename: Ns
authors.initials: N
authors.lastname: Michalany
authors.forename: Mamm
authors.initials: M
authors.lastname: Abreu
authors.forename: Rc
authors.initials: R
authors.lastname: Borra
keywords: Actinic keratosis; histopathology; immunohistochemical; p53; squamous cell carcinoma
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