title: Significance of podoplanin expression in keratocystic odontogenic tumor.
abstract: BACKGROUND
  The most important clinical features of the keratocystic odontogenic tumor (KCOT) are its potential for locally destructive behavior, a tendency to recur, and its origin in the odontogenic epithelium. The clinical features of KCOT are similar to those of ameloblastoma (AM). Histologically, KCOT is distinguished from jaw cyst with keratinization (orthokeratinized odontogenic cyst; OOC). However, current scientifically based clinical parameters cannot predict any potential for neoplastic behavior, or aggressive and localized invasiveness, in patients with KCOT. We have shown that podoplanin, a lymphatic endothelial marker, is highly expressed in AM. The purpose of this study was to determine the usefulness of podoplanin for reclassification of the odontogenic keratocyst (OKC) from cyst to tumor status.
  
  
  METHODS
  Paraffin-embedded tissue specimens of 57 OKCs (46 KCOTs and 11 OOCs) and 15 dentigerous cysts (DCs) were immunohistochemically examined using antibody against podoplanin.
  
  
  RESULTS
  Immunohistochemical reactivity for podoplanin was detected in the cell membrane and cytoplasm of most of the basal and suprabasal layer, areas of budding basal cell proliferation, epithelial nests and peripheral cells of daughter cysts in the stromal connective tissue in KCOTs. In the case of OOC and DC, only cases associated with inflammation were positive for podoplanin.
  
  
  CONCLUSIONS
  Podoplanin is strongly expressed in KCOTs in comparison with OOCs. The pattern of staining for podoplanin in KCOT could be related to its neoplastic nature, and suggests a role of the protein in tumor invasiveness.
authors.affiliation: Division of Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Okamoto
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kikuchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Patricia
authors.initials: P
authors.lastname: González-Alva
authors.forename: Yuka
authors.initials: Y
authors.lastname: Oku
authors.forename: Akio
authors.initials: A
authors.lastname: Tanaka
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yoshida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujinami
authors.forename: Fumio
authors.initials: F
authors.lastname: Ide
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sakashita
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kusama
mesh_terms: D002462:Cell Membrane / Q000648:ultrastructure; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D003239:Connective Tissue Cells / Q000473:pathology; D003593:Cytoplasm / Q000648:ultrastructure; D003803:Dentigerous Cyst / Q000473:pathology; D018450:Disease Progression; D042783:Endothelial Cells / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D006801:Humans; D042601:Lymphatic Vessels / Q000473:pathology; D008562:Membrane Glycoproteins / Q000032:analysis*; D009061:Mouth Mucosa / Q000473:pathology; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009807:Odontogenic Cysts / Q000473:pathology*; D009808:Odontogenic Tumors / Q000473:pathology*; D017154:Stromal Cells / Q000473:pathology; D000098853:Podoplanin
chemical_list: D008562:Membrane Glycoproteins; C117468:PDPN protein, human; D000098853:Podoplanin