title: Fluorescence spectroscopy of epithelial tissue throughout the dysplasia-carcinoma sequence in an animal model: spectroscopic changes precede morphologic changes.
abstract: OBJECTIVE
  The hamster cheek pouch carcinogenesis model, using chronic treatments of dimethylbenz[alpha]anthracene (DMBA) was used as a model system to investigate changes in epithelial tissue autofluorescence throughout the dysplasia-carcinoma sequence.
  
  
  METHODS
  Fluorescence emission spectra were measured weekly from 42 DMBA-treated animals and 20 control animals at 337, 380, and 460 nm excitation. A subset of data in which histopathology was available was used to develop diagnostic algorithms to separate neoplastic and non-neoplastic tissue. The change in fluorescence intensity over time was examined in all samples at excitation-emission wavelength pairs identified as diagnostically useful.
  
  
  RESULTS
  Algorithms based on autofluorescence can separate neoplastic and non-neoplastic tissue with 95% sensitivity and 93% specificity. Greatest contributions to diagnostic algorithms are obtained at 380 nm excitation, and 430, 470, and 600 nm emission. Changes in fluorescence intensity are apparent as early as 3 weeks after initial treatment with DMBA, whereas morphologic changes associated with dysplasia occur on average at 7.5-12.5 weeks after initial treatment.
  
  
  CONCLUSIONS
  Fluorescence spectroscopy provides a potential tool to identify biochemical changes associated with dysplasia and hyperplasia, which precede morphologic changes observed in histologically stained sections.
authors.affiliation: Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, Science Park, Bastrop, Texas, USA.
authors.forename: L
authors.initials: L
authors.lastname: Coghlan
authors.forename: U
authors.initials: U
authors.lastname: Utzinger
authors.forename: R
authors.initials: R
authors.lastname: Richards-Kortum
authors.forename: C
authors.initials: C
authors.lastname: Brookner
authors.forename: A
authors.initials: A
authors.lastname: Zuluaga
authors.forename: I
authors.initials: I
authors.lastname: Gimenez-Conti
authors.forename: M
authors.initials: M
authors.lastname: Follen
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000465:Algorithms; D000818:Animals; D002277:Carcinoma / Q000139:chemically induced / Q000209:etiology / Q000473:pathology*; D002610:Cheek; D006224:Cricetinae; D004848:Epithelium; D013050:Spectrometry, Fluorescence; D013997:Time Factors
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene