Fluorescence spectroscopy of epithelial tissue throughout the dysplasia-carcinoma sequence in an animal model: spectroscopic changes precede morphologic changes.
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.
Coghlan
L
L
Department of Veterinary Sciences, The University of Texas M.D. Anderson Cancer Center, Science Park, Bastrop, Texas, USA.
Utzinger
U
U
Richards-Kortum
R
R
Brookner
C
C
Zuluaga
A
A
Gimenez-Conti
I
I
Follen
M
M
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
D015127:9,10-Dimethyl-1,2-benzanthracene