title: Expression Patterns of Gli-1, Pleckstrin Homology-Like Domain, Family A, Member 1, Transforming Growth Factor-β1/β2, and p63 in Sebaceous and Follicular Tumors.
abstract: BACKGROUND
  Certain epidermal appendage tumors, including hyperplasias (hamartomas), adenomas, benign epitheliomas, primordial epitheliomas, and malignant tumors, can exhibit any stage of differentiation. Several molecules associated with tumorigenesis, such as Gli-1, pleckstrin homology-like domain, family A, member 1 (PHLDA-1), transforming growth factor (TGF)-β1, TGF-β2, and p63, are associated with tumor grade and aggressive behavior in follicular and sebaceous tumors in ways that are not well understood.
  
  
  OBJECTIVE
  The aim of this study was to elucidate the expression of Gli-1, PHLDA-1, TGF-β1/β2, and p63 in benign and malignant tumors of the hair and sebaceous glands and to determine their importance in the degree of tumor differentiation.
  
  
  METHODS
  Immunohistochemistry was performed in follicular and sebaceous tumors using antibodies against Gli-1 (sebaceous tumor marker), PHLDA-1 (hair follicle outer root sheath [ORS] cell marker), p63, TGF-β1, and TGF-β2.
  
  
  RESULTS
  Gli-1 was expressed in basaloid cells, sebocytes, and sebaceous carcinoma cells, and expression levels decreased as differentiation progressed. PHLDA-1 was expressed in ORS cells and some follicular tumor cells. Expression of p63 was observed in the nuclei of the outermost basaloid cells (seboblasts), poorly differentiated sebaceous carcinoma cells, and tumor cells toward the direction of the hair. Remarkably, TGF-β1 was expressed exclusively in the nuclei of benign and malignant follicular (hair) tumors, but not in sebaceous tumors, at levels that correlated with the degree of differentiation.
  
  
  CONCLUSIONS
  We propose that p63 and/or TGF-β1 are useful for predicting the degree of differentiation and malignant potential of sebaceous and follicular tumors and for distinguishing trichilemmal carcinoma from sebaceous carcinoma.
authors.affiliation: Department of Dermatology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Jeon
authors.affiliation: Department of Pathology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Dae-Cheol
authors.initials: DC
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Ki-Hoon
authors.initials: KH
authors.lastname: Song
authors.affiliation: Department of Dermatology, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Ki-Ho
authors.initials: KH
authors.lastname: Kim
keywords: Follicular tumor; Gli-1; PHLDA-1; Sebaceous tumor; Transforming growth factor-β1; p63