title: Expression of cdk4 and p16 in Oral Lichen Planus.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the expression of cdk4 and p16, the proteins implicated in hyperproliferation and arrest in oral lichen planus and to compare their expression in erosive and non-erosive oral lichen planus and with normal mucosa and oral squamous cell carcinoma.
  
  
  METHODS
  Analysis of cdk4 and p16 expression was done in 43 erosive oral lichen planus (EOLP) and 17 non-erosive oral lichen planus (NOLP) cases, 10 normal mucosa and 10 oral squamous cell carcinoma (OSCC) cases with immunohistochemistry.
  
  
  RESULTS
  This study demonstrated a significantly increased expression of cytoplasmic cdk4 (80% cases, cells stained - 19.6%), and cytoplasmic p16 (68.3% cases, cells stained - 16.4%) in oral lichen planus (OLP) compared to normal mucosa. cdk4 was much higher in OSCC in both cytoplasm and nuclei compared to normal mucosa. Also, while comparing OLP with positive control, significant difference was noted for cdk4 and p16, with expression being more in OSCC. While comparing EOLP with NOLP; significant differences were seen for cdk4 cytoplasmic staining only, for number of cases with positive staining as well as number of cells stained.
  
  
  CONCLUSIONS
  Overexpression of cytoplasmic cdk4 and p16 was registered in oral lichen planus, however considerably lower than in squamous cell carcinoma. Erosive oral lichen planus demonstrated overexpression of cytoplasmic cdk4 and premalignant nature compared to non-erosive lesion. Therefore there is an obvious possibility for cytoplasmic expression of cdk4 and p16 to predict malignant potential of oral lichen planus lesions.
authors.affiliation: Department of Oral Medicine and Radiology, Maulana Azad Institute of Dental Sciences, New Delhi India.
authors.forename: Sinny
authors.initials: S
authors.lastname: Goel
authors.affiliation: Department of Pathology, Maulana Azad Medical College, New Delhi India.
authors.forename: Nita
authors.initials: N
authors.lastname: Khurana
authors.affiliation: Department of Oral Medicine and Radiology, Maulana Azad Institute of Dental Sciences, New Delhi India.
authors.forename: Akanksha
authors.initials: A
authors.lastname: Marwah
authors.affiliation: Department of Oral Medicine and Radiology, Maulana Azad Institute of Dental Sciences, New Delhi India.
authors.forename: Sunita
authors.initials: S
authors.lastname: Gupta
keywords: cell cycle checkpoints; immunohistochemistry; lichen planus