title: Short telomeres in an oral precancerous lesion: Q-FISH analysis of leukoplakia.
abstract: OBJECTIVE
  A precancerous condition is a lesion that, if left untreated, leads to cancer or can be induced to become malignant. In the oral region, leukoplakia is a lesion that has been regarded as precancerous. In cases of oral carcinoma, we have frequently noticed that a type of leukoplakia histologically demonstrating hyper-orthokeratosis and mild atypia (ortho-keratotic dysplasia; OKD) is often associated with carcinoma, either synchronously or metachronously. Therefore, we consider OKD-type leukoplakia to be a true precancerous lesion.
  
  
  METHODS
  In an attempt to clarify the relationship between OKD as a precancerous condition in the oral mucosa and telomere length, we estimated telomere lengths in this type of leukoplakia using quantitative fluorescence in situ hybridization, and also quantified the frequency of anaphase-telophase bridges (ATBs) in comparison with squamous cell carcinoma in situ (CIS) and the background tissues of CIS and OKD.
  
  
  RESULTS
  Ortho-keratotic dysplasia was frequently associated with squamous cell carcinoma (45.0%) and showed significantly shorter telomeres than normal control epithelium, CIS, or the background of CIS or OKD. The frequency of ATBs was much higher in OKD than in control epithelium or CIS.
  
  
  CONCLUSIONS
  Ortho-keratotic dysplasia appears to be frequently associated with carcinoma, chromosomal instability, and excessively shortened telomeres, not only in the lesion itself but also in the surrounding background. Therefore, when this type of leukoplakia is recognized in the oral region, strict follow-up for oral squamous cell carcinoma is necessary, focusing not only on the areas of leukoplakia, but also the surrounding background.
authors: Research Team for Geriatric Pathology, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan. aidajs@tmig.or.jp
authors: Junko
authors: J
authors: Aida
authors: Takanori
authors: T
authors: Kobayashi
authors: Takashi
authors: T
authors: Saku
authors: Masatsune
authors: M
authors: Yamaguchi
authors: Naotaka
authors: N
authors: Shimomura
authors: Ken-Ichi
authors: K
authors: Nakamura
authors: Naoshi
authors: N
authors: Ishikawa
authors: Satoshi
authors: S
authors: Maruyama
authors: Jun
authors: J
authors: Cheng
authors: Steven S S
authors: SS
authors: Poon
authors: Motoji
authors: M
authors: Sawabe
authors: Tomio
authors: T
authors: Arai
authors: Kaiyo
authors: K
authors: Takubo
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology*; D043171:Chromosomal Instability; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007642:Keratosis; D007972:Leukoplakia, Oral / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000235:genetics / Q000473:pathology* / Q000517:prevention & control; D011230:Precancerous Conditions / Q000235:genetics / Q000473:pathology; D059506:Telomere Shortening