title: Immunohistochemical location of the p75 neurotrophin receptor (p75NTR) in oral leukoplakia and oral squamous cell carcinoma.
abstract: BACKGROUND
  Recent studies have demonstrated that the p75 neurotrophin receptor (p75NTR) is a useful marker of keratinocyte stem cells. Although the stem cell markers of original normal tissue have been used to identify cancer stem cells in a variety of cancers, the expression and function of p75NTR have been poorly understood in oral squamous cell carcinoma (OSCC). The objective of this study is, thus, to examine p75NTR expression immunohistochemically in oral leukoplakia (OL), the most frequent precancerous lesion, and OSCC, and to reveal the usefulness of p75NTR as a marker for undifferentiated cancer cells and a novel prognostic factor for OSCC patients.
  
  
  METHODS
  In this study immunohistochemical expression of p75NTR, Ki-67, cytokeratin (CK) 5, and CK14 was examined in 112 cases of OL and 81 of OSCC. The labeling indices (LIs) of p75NTR and Ki-67 were calculated, and the association of these LIs with histopathologic characteristics was then evaluated.
  
  
  RESULTS
  In the normal oral epithelium and OL, p75NTR was expressed only in the basal layer, and its LI was invariant, irrespective of the extent of epithelial dysplasia. In OSCC, however, p75NTR-LI was significantly increased in association with upgrading of histologic grade and mode of tumor invasion. Furthermore, the prognosis of the high p75NTR-LI group (LI ≥ 53.1%) was poorer than that of the low p75NTR-LI group (LI < 53.1%).
  
  
  CONCLUSIONS
  These results suggest that p75NTR is expressed in undifferentiated cell populations in OL and OSCC. Furthermore, p75NTR is possibly involved in invasion and poor prognosis in OSCC.
authors.affiliation: Section of Oral and Maxillofacial Oncology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kiyosue
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kawano
authors.forename: Ryota
authors.initials: R
authors.lastname: Matsubara
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Goto
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Hirano
authors.forename: Teppei
authors.initials: T
authors.lastname: Jinno
authors.forename: Takeshi
authors.initials: T
authors.lastname: Toyoshima
authors.forename: Ryoji
authors.initials: R
authors.lastname: Kitamura
authors.forename: Kazunari
authors.initials: K
authors.lastname: Oobu
authors.forename: Seiji
authors.initials: S
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D007972:Leukoplakia, Oral / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000378:metabolism / Q000473:pathology; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011379:Prognosis; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor