Diagnosis of early stage nasopharyngeal carcinoma using ultraviolet autofluorescence excitation–emission matrix spectroscopy and parallel factor analysis

Abstract

We report the diagnostic ability of ultraviolet (UV)-excited autofluorescence (AF) excitation-emission matrix (EEM) spectroscopy associated with parallel factor (PARAFAC) analysis for differentiating cancer from normal nasopharyngeal tissue. A bifurcated fiber-optic probe coupled with an EEM system was used to acquire tissue AF EEMs using excitation wavelengths between 260 and 400 nm, and emission collection between 280 and 500 nm. A total of 152 AF EEM landscapes were acquired from 13 normal and 16 nasopharyngeal carcinoma (NPC) thawed ex vivo tissue samples from 23 patients. PARAFAC was introduced for curve resolution of individual AF EEM landscapes associated with the endogenous tissue constituents. The significant factors were further fed to a support vector machine (SVM) and cross-validated to construct diagnostic algorithms. Both the EEM intensity landscapes and the PARAFAC model revealed tryptophan, collagen, and elastin to be the three major endogenous fluorophores responsible for the AF signal from normal and NPC tissues. The EEM intensity distribution and PARAFAC factors suggest an increase of tryptophan and a decrease of collagen and elastin in NPC tissues compared to the normal. The classification results obtained from the PARAFAC-SVM modeling yielded a diagnostic accuracy of 94.7% (sensitivity of 95.0% (76/80); specificity of 94.4% (68/72)) for normal and NPC tissue differentiation. This study suggests that UV-excited AF EEM spectroscopy integrated with PARAFAC algorithms has the potential to provide clinical diagnostics of early onset and progression of NPC.

High sensitivity of gold nanoparticles co-doped with Gd2O3 mesoporous silica nanocomposite to nasopharyngeal carcinoma cells

“…Studies have shown that each endogenous fluorophore possesses its own emission band and wavelength maximum 33 . In our experiment, the 400 nm-excited lifetime images were obtained in the 525-nm channel, which have deviated from the emission peaks of the endogenous fluorophores with a high sensitivity to NPC 17 33 ; such a deviation may have led to the absence of significant differences in AF lifetimes between normal (NP69 and MSC) and cancerous (CNE-2) cells 33 . The luminescence spectra (the colour curves) of CNE-2, NP69 and MSC cells after the uptake of Au/Gd@MCM-41 are also shown in Fig.…”

“…The detection of autofluorescence (AF) allows the investigation of the epithelial layer, as the vast majority of nasopharyngeal tumours initiate in the epithelial tissue layer 17 . Many key endogenous fluorophores are specific to normal and cancerous NP cells and produce a strong autofluorescence (AF) signal under ultraviolet (UV) excitation between 260 and 400 nm 17 . Figure 3(a,b) show the AF spectra (black curves) and the FLIM images of AF from NP69 and CNE-2 cells, respectively, at 525 nm.…”

“…Nasopharyngeal carcinoma (NPC) is one of the most common cancers in Southeast Asia, with the highest incidence rates in the Guangdong province of China, Hong Kong, Malaysia, Indonesia, and Singapore, where NPC occurs 10–50 times more frequently than in Western countries 17 18 . Based on the 1978 WHO classification, all NPCs are histopathologically diagnosed as poorly differentiated squamous cell carcinomas 19 .…”

Establishment of rules for interpreting ultraviolet autofluorescence microscopy images for noninvasive detection of Barrett’s esophagus and dysplasia

“…This approach could employ powerful algorithms, such as parallel factor analysis (PARAFAC) conducted for the first time on biological tissues to differentiate carcinoma from normal nasopharyngeal tissue. 35 Analogous to the confocal Barrett's classification, Table 1 serves as a foundation from which to build on. 25,26 As it has taken decades to correlate abstract images of stained tissue sections and establish traditional histology, a similar effort may be needed to establish the correlation of characteristic features observed in the images obtained using new technologies such as the UV AF microscopy method discussed in this work.…”

Modern Trends in Imaging X: Spectral Imaging in Preclinical Research and Clinical Pathology

“…Alternatively, autofluorescence arising from "interesting" endogenous molecules may also carry useful spectroscopic information. Autofluorescence spectra of, for example, NAD(P)H [53], flavins and flavoproteins [54], advanced glycation end-products (AGEs) [55], collagen and elastin [56], lipofuscins [57] and protoporphyrin IX [58] can provide insights into normal and pathological specimens [59,60].…”