title: Detection and diagnosis of oral cancer by light-induced fluorescence.
abstract: OBJECTIVE
  New techniques for non-invasive early detection and diagnosis of oral dysplasia and carcinoma are required. Our objective was to determine in the hamster cheek pouch model whether differentiation between the healthy tissue and the different stages of oral premalignancy and malignancy is possible using laser-induced fluorescence after tissue exposure to 5-Aminolevulinic acid (ALA).
  
  
  METHODS
  DMBA carcinogenesis was applied to one cheek pouch in 18 hamsters for 0-20 weeks. Prior to sacrifice, 20% ALA was applied to the cheek tissues. Excised cheek tissues were cryosectioned and imaged using fluorescence microscopy with excitation at 405 nm, detection at 635 nm. After fluorescence measurement, H&E staining and histopathological evaluation were performed.
  
  
  RESULTS
  Fluorescence intensity was significantly lower in healthy tissue than in pathological tissues. Significantly higher intensities and more "fluorescence hot spots" occurred in severe dysplasia and carcinoma than in healthy tissue, hyperkeratosis, mild and moderate dysplasia.
  
  
  CONCLUSIONS
  Light-induced fluorescence after ALA exposure can differentiate between the different stages of premalignancy and malignancy. Its ability to differentiate between healthy tissue and early pathology is particularly interesting
authors.affiliation: Beckman Laser Institute and Medical Clinic, University of California at Irvine, Irvine, California 92612, USA.
authors.forename: Arata
authors.initials: A
authors.lastname: Ebihara
authors.forename: Tatiana B
authors.initials: TB
authors.lastname: Krasieva
authors.forename: Lih-Huei L
authors.initials: LH
authors.lastname: Liaw
authors.forename: Sheri
authors.initials: S
authors.lastname: Fago
authors.forename: Diana
authors.initials: D
authors.lastname: Messadi
authors.forename: Kathryn
authors.initials: K
authors.lastname: Osann
authors.forename: Petra
authors.initials: P
authors.lastname: Wilder-Smith
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000009:adverse effects; D000622:Aminolevulinic Acid / Q000008:administration & dosage; D000818:Animals; D002273:Carcinogens / Q000009:adverse effects; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000175:diagnosis*; D002610:Cheek / Q000473:pathology / Q000528:radiation effects*; D006224:Cricetinae; D003937:Diagnosis, Differential; D004195:Disease Models, Animal; D028022:Low-Level Light Therapy; D008856:Microscopy, Fluorescence; D009062:Mouth Neoplasms / Q000139:chemically induced / Q000175:diagnosis*; D009367:Neoplasm Staging; D017319:Photosensitizing Agents / Q000008:administration & dosage; D013997:Time Factors
chemical_list: D002273:Carcinogens; D017319:Photosensitizing Agents; D015127:9,10-Dimethyl-1,2-benzanthracene; D000622:Aminolevulinic Acid