title: Expression of Phosphatase and Tensin Homologue, phospho-Akt, and p53 in Acral Benign and Malignant Melanocytic Neoplasms (Benign Nevi, Dysplastic Nevi, and Acral Melanomas).
abstract: BACKGROUND
  The role of the phosphatidylinositol-3 kinase signaling pathway in the development of acral melanoma has recently gained evidence. Phosphatase and tensin homologue (PTEN), one of the key molecules in the pathway, acts as a tumor suppressor through either an Akt-dependent or Akt-independent pathway. Akt accelerates degradation of p53.
  
  
  OBJECTIVE
  We assessed the expression of PTEN, phospho-Akt (p-Akt), and p53 by immunohistochemistry in benign acral nevi, acral dysplastic nevi, and acral melanomas in the radial growth phase and with a vertical growth component.
  
  
  METHODS
  Ten specimens in each group were included. Paraffin-embedded specimens were immunostained with antibodies for PTEN, p-Akt, and p53. We scored both the staining intensity and the proportion of positive cells. The final score was calculated by multiplying the intensity score by the proportion score.
  
  
  RESULTS
  All specimens of benign acral nevi except one showed some degree of PTEN-negative cells. The numbers of p-Akt and p53-positive cells were higher in acral dysplastic nevi and melanoma than in benign nevi. P-Akt scores were 1.7, 1.8, 2.6, and 4.4, and p53 scores were 2.0, 2.1, 3.8, and 4.1 in each group. PTEN and p-Akt scores in advanced acral melanoma were higher than in the other neoplasms.
  
  
  CONCLUSIONS
  The expression of PTEN was decreased and the expression of p-Akt was increased in acral melanoma, especially in advanced cases. The PTEN-induced pathway appears to affect the late stage of melanomagenesis. Altered expression of p-Akt is thought to be due to secondary changes following the loss of PTEN.
authors.affiliation: Department of Dermatology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: So Min
authors.initials: SM
authors.lastname: Lyu
authors.affiliation: Department of Dermatology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Ju Yeon
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Department of Dermatology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Byun
authors.affiliation: Department of Dermatology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Hae Young
authors.initials: HY
authors.lastname: Choi
authors.affiliation: Department of Pathology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Sang Hee
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Dermatology, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: You Won
authors.initials: YW
authors.lastname: Choi
keywords: Acral; Akt; Melanocytic; PTEN; p53