title: Cell proliferation, apoptosis and apoptosis-related factors in odontogenic keratocysts and in dentigerous cysts.
abstract: BACKGROUND
  The purpose of this study was to elucidate why odontogenic keratocysts (OKC) can form cystic lesions but not tumor masses, notwithstanding their prominent proliferative activity.
  
  
  METHODS
  We investigated cellular proliferation, cell death, and expression of apoptosis-related proteins in the lining cells of OKCs and of dentigerous cysts (DGCs).
  
  
  RESULTS
  TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells were observed in the surface layers of OKCs and of DGCs. However, no TUNEL-positive cells were seen in the basal or intermediate layers of both cysts. Ki67-positive ratio in the intermediate layer was the highest in OKCs. The p53-positive ratio of the intermediate layer was highest in OKCs. Bcl-2-positive cells were discernible exclusively in the basal layer of OKCs.
  
  
  CONCLUSIONS
  These results suggest that cellular proliferation and death is regulated in association with apoptosis-related proteins in the lining epithelia of OKCs, and subsequently those cysts are seen as cystic lesions but not as tumor masses.
authors.affiliation: Department of Pathology, Tokyo Dental College, Mihama-ku, Chiba 261-8502, Japan.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Kichi
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Enokiya
authors.forename: Takashi
authors.initials: T
authors.lastname: Muramatsu
authors.forename: Sadamitsu
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Abiko
authors.forename: Masaki
authors.initials: M
authors.lastname: Shimono
mesh_terms: D017209:Apoptosis; D049109:Cell Proliferation; D003803:Dentigerous Cyst / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000032:analysis / Q000378:metabolism; D009807:Odontogenic Cysts / Q000378:metabolism* / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000378:metabolism*; D018709:Statistics, Nonparametric; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000378:metabolism
chemical_list: D019394:Ki-67 Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53