title: Infrared imaging as a cancer diagnostic tool: introducing a new concept of spectral barcodes for identifying molecular changes in colon tumors.
abstract: Complementary diagnostic methods to conventional histopathology are under scrutiny for various types of cancers for rapid and molecular level diagnostics. In this perspective, a biophotonic approach based on infrared spectral micro-imaging combined with multivariate statistical analysis has been implemented on colon tissues. The ability of infrared imaging to investigate the intrinsic biochemical features of cells and tissues has been exploited to develop a new concept of spectral bar coding. To implement this concept, 10 frozen colon tissue samples (five nontumoral and tumoral pairs from five patients) were imaged using infrared spectral micro-imaging in a nondestructive manner. The spectral images were processed by a multivariate clustering method to identify the histological organization in a label-free manner. Spectral information from the epithelial components was then automatically recovered on the basis of their intrinsic biochemical composition, and compared using a statistical method (Mann-Whitney U-test) to construct spectral barcodes specific to each patient. The spectral barcodes representing the discriminant infrared spectral wavenumbers (900-1,800 cm(-1) ) enabled characterization of some of the malignancy-associated biochemical alterations associated with mucin, nucleotides, carbohydrates, and protein regions. This approach not only allowed the identification of common biochemical alterations among all the colon cancer patients, but also revealed a difference of gradient within individual patients. This new concept of spectral bar coding gives insight into the potential of infrared spectral micro-imaging as a complementary diagnostic tool to conventional histopathology, for biochemical level understanding of malignancy in colon cancers in an objective and label-free manner.
authors.affiliation: MéDIAN Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, FRE CNRS 3481 MEDyC, UFR de Pharmacie, SFR Cap Santé, 51096 Reims Cedex, France.
authors.forename: Jayakrupakar
authors.initials: J
authors.lastname: Nallala
authors.forename: Olivier
authors.initials: O
authors.lastname: Piot
authors.forename: Marie-Danièle
authors.initials: MD
authors.lastname: Diebold
authors.forename: Cyril
authors.initials: C
authors.lastname: Gobinet
authors.forename: Olivier
authors.initials: O
authors.lastname: Bouché
authors.forename: Michel
authors.initials: M
authors.lastname: Manfait
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Sockalingum
mesh_terms: D003110:Colonic Neoplasms / Q000175:diagnosis*; D003952:Diagnostic Imaging / Q000379:methods*; D006801:Humans; D007259:Infrared Rays; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D015999:Multivariate Analysis; D013055:Spectrophotometry, Infrared