title: Cytokeratin 19 expression patterns of dentigerous cysts and odontogenic keratocysts.
abstract: BACKGROUND
  Although numerous investigators have studied the pattern of keratin expression in different odontogenic cysts, the results have been variable.
  
  
  OBJECTIVE
  The present study was conducted to determine the pattern of expression of cytokeratin 19 (CK 19) in the epithelial lining of odontogenic keratocysts and dentigerous cysts.
  
  
  METHODS
  The epithelial layers showing expression of the epithelial marker CK 19 was determined by immunohistochemical methods in 15 tissue specimens each of histopathologically confirmed cases of dentigerous cysts and odontogenic keratocysts. Statistical analysis was done to compare the CK 19 expression between dentigerous cyst and odontogenic keratocyst using the Chi-square test. P < 0.05 was considered to be statistically significant.
  
  
  RESULTS
  All specimens of dentigerous cysts were positive for CK 19 with 20% (3/15) of the specimens showing expression only in a single layer of the epithelium, 40% (6/15) of the specimens showing expression in more than one layer but not the entire thickness of the epithelium, and the remaining 40% (6/15) showing expression throughout the entire thickness of the epithelium. In the case of odontogenic keratocysts, 40% (6/15) of the specimens were negative for CK 19, 40% (6/15) of the specimens showed expression only in a single layer of the epithelium, and 20% (3/15) of the specimens showed expression in more than one layer, but not the entire thickness of the epithelium. The observed differences in CK 19 expression by the two lesions were statistically significant (P < 0.01).
  
  
  CONCLUSIONS
  The differences in CK 19 expression by these cysts may be utilized as a diagnostic tool in differentiating between these two lesions.
authors: Department of Oral Pathology, People's Dental Academy, Bhanpur, Bhopal, Madhya Pradesh, India.
authors: K P
authors: KP
authors: Kamath
authors: Department of Oral Pathology, Malabar Dental College and Research Centre, Edappal, Malappuram, Kerala, India.
authors: M
authors: M
authors: Vidya
keywords: Dentigerous cyst; Immunohistochemistry; Keratins; Odontogenic cyst