title: Discrimination between nontumor bladder tissue and tumor by Raman spectroscopy.
abstract: We have applied Raman spectroscopy to discriminate between nontumor and tumor bladder tissue and to determine the biochemical differences therein. Tissue samples from 15 patients were collected, and frozen sections were made for Raman spectroscopy and histology. Twenty-five pseudocolor Raman maps were created in which each color represents a cluster of spectra measured on tissue areas of similar biochemical composition. For each cluster, the cluster-averaged spectrum (CAS) was calculated and classified as tumor and nontumor in accordance to pathohistology. Unguided hierarchical clustering was applied to display heterogeneity between and within groups of nontumor and tumor CAS. A linear discriminant analysis model was developed to discriminate between CAS from tumor and nontumor. The model was tested by a leave-one-patient-out validation, 84 of the 90 CAS (93%) were correctly classified with 94% sensitivity and 92% specificity. Biochemical differences between tumor and nontumor CAS areas were analyzed by fitting spectra of pure compounds to the CAS. Nontumor CAS showed higher collagen content while tumor CAS were characterized by higher lipid, nucleic acid, protein, and glycogen content. Raman spectroscopy enabled effective discrimination between tumor and nontumor bladder tissue based on characterized biochemical differences, despite heterogeneity expressed in both tumor and nontumor CAS.
authors.affiliation: Department of Pediatric Urology, Center for Optical Diagnostics & Therapy, Erasmus MC, Dr. Molewaterplein 50, 3015 GE, Rotterdam, The Netherlands. b.dejong@erasmusmc.nl
authors.forename: Bas W D
authors.initials: BW
authors.lastname: de Jong
authors.forename: Tom C Bakker
authors.initials: TC
authors.lastname: Schut
authors.forename: Kees
authors.initials: K
authors.lastname: Maquelin
authors.forename: Theo
authors.initials: T
authors.lastname: van der Kwast
authors.forename: Chris H
authors.initials: CH
authors.lastname: Bangma
authors.forename: Dirk-Jan
authors.initials: DJ
authors.lastname: Kok
authors.forename: Gerwin J
authors.initials: GJ
authors.lastname: Puppels
mesh_terms: D016000:Cluster Analysis; D003094:Collagen / Q000032:analysis; D016002:Discriminant Analysis; D005629:Frozen Sections; D006003:Glycogen / Q000032:analysis; D006801:Humans; D016014:Linear Models; D008055:Lipids / Q000032:analysis; D008954:Models, Biological; D009696:Nucleic Acids / Q000032:analysis; D011506:Proteins / Q000032:analysis; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods*; D001743:Urinary Bladder / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
chemical_list: D008055:Lipids; D009696:Nucleic Acids; D011506:Proteins; D006003:Glycogen; D003094:Collagen