Investigation of malignant transformation of sporadic adenomas of colon by fluorimetry

Abstract

In this work, biochemical changes in sporadic adenoma during progression to colon cancer have been detected by spectral techniques. It is shown that spectra of all types of adenomas as well as adenocarcinoma have two maxima at 265 ÷ 270 nm and at 330 ÷ 340 nm. The first maximum is primarily defined by tryptophan containing peptides. The second maximum of the spectra is in the main defined by collagen presence in stroma of tumors and normal mucosa. Progression of precancer lesions to advanced cancer leads to increase of NADH concentration impacting on the second maximum of spectra. At the time, the spectra of both AC differ from each other by widths of the second maximum. For well-differentiated AC, the second maximum is wider. It gives reason to suggest that two fluorophores impact on its intensity. These fluorophores can be NADH and vitamin B. Correlation between microscopical and spectral results can allow to use fluorimetry for detail diagnostics and investigation of colon cancer development.

Fluorescent diagnostics of epithelial neoplasms of different colon parts

“…These curves differ from each other by maxima width and their intensity. However, both maxima of CC spectra have significantly higher intensity than for adenomas .…”

Identifying molecular contributors to autofluorescence of neoplastic and normal colon sections using excitation-scanning hyperspectral imaging

“…To assess the relative contribution of each autofluorescent molecule to the bulk spectral signature of each specimen, we created an excitation-based spectral library of components known to be both autofluorescent and present in colorectal tissue. [31][32][33][34][35] Excitation spectral data reported in the literature are frequently only reported in terms of peak excitation. 31 However, using only the peak intensity wavelength does not provide sufficient information for identifying many molecular signatures in tissue.…”

“…This suggests that the overall spectral response in normal colon tissue has a more defined signature whereas neoplastic specimens differ from this signature with increased variability, possibly due to variation in changes of cellular and extracellular matrix (ECM) composition associated with remodeling of the tumor environment. 32,33,35,43 Variation from a defined signature was more evident when data from normal colon specimens and neoplastic specimens were compared within a single patient (Fig. 6).…”

“…34,48 Additionally, disruption of the metabolic cycle in neoplastic cells can result in changes in FAD and NADH concentrations. 32,33,35,49 Estimating the relative contributions of collagen, elastin, FAD, and NADH in neoplastic and normal tissues may provide a mechanism for detecting cancer-related changes in the ECM. [50][51][52] LSU was used to estimate relative abundances of autofluorescent molecules, allowing estimation of localized fluorophore relative concentration ( Fig.…”

“…29 Colorectal cancer is known to cause changes in the concentration of at least five autofluorescent molecules: collagen, elastin, flavin adenine dinucleotide (FAD), nicotinamide adenine dinucleotide (NADH), and protoporphyrin IX (PPIX). [31][32][33][34][35] To evaluate the feasibility of excitation-scanning hyperspectral imaging for detecting these autofluorescent molecules, an excitation range of 360 to 550 nm was selected, and the excitation spectra of these endogenous autofluorescent molecules were measured. Spectral image data were then acquired from pairs of normal and neoplastic colorectal tissues.…”