In vivo Fluorescence Spectroscopy of Nonmelanoma Skin Cancer¶

Abstract

In vivo and ex vivo tissue autofluorescence (endogenous fluorescence) have been employed to investigate the presence of markers that could be used to detect tissue abnormalities and/or malignancies. We present a study of the autofluorescence of normal skin and tumor in vivo, conducted on 18 patients diagnosed with nonmelanoma skin cancers (NMSC). We observed that both in basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) the endogenous fluorescence due to tryptophan residues was more intense in tumor than in normal tissue, probably due to epidermal thickening and/or hyperproliferation. Conversely, the fluorescence intensity associated with dermal collagen crosslinks was generally lower in tumors than in the surrounding normal tissue, probably because of degradation or erosion of the connective tissue due to enzymes released by the tumor. The decrease of collagen fluorescence in the connective tissue adjacent to the tumor loci was validated by fluorescence imaging on fresh‐frozen tissue sections obtained from 33 NMSC excised specimens. Our results suggest that endogenous fluorescence of NMSC, excited in the UV region of the spectrum, has characteristic features that are different from normal tissue and may be exploited for noninvasive diagnostics and for the detection of tumor margins.

Enhancement factor in low-coherence enhanced backscattering and its applications for characterizing experimental skin carcinogenesis

“…Recent studies about skin cancer also suggest that squamous cell carcinoma leads to decreased scattering power in the dermis probably due to degradation of collagen crosslinks. 28,29 Similar findings were observed in other types of epithelia cancers such as oral and cervical cancers. [30][31][32] Our result is consistent with these studies, although our study time points are at a stage of preneoplasia.…”

Identification of skin lesions through aminolaevulinic acid-mediated photodynamic detection

“…The observed LOF from the abnormal skin has been also described in other studies [12,23,24], and this is mainly justified by the decrease in collagen fluorescence caused by fiber linkage breakdown [25]. Others skin components such as flavins do not have a great contribution due to the excitation wavelength, which is not within the absorption wavelengths of these components [26].…”

“…Among optical techniques for tissue diagnostics, one of the most investigated one is autofluorescence [11][12][13][14], because tissue biochemical and structural changes that take place during cancer development and progression alter the light-tissue interactions. Tissue fluorescence patterns also depend on these interactions.…”

“…At skin, autofluorescence helps in the detection and delineation of tumor margins, limiting damage caused by the tumor recurrence due to an incomplete surgical removal [11]. The use of skin fluorescence also aids in distinguishing tumor from healthy tissue [12] and benign lesions [13].…”

Steady-state directional diffuse reflectance and fluorescence of human skin

“…Brancaleon et al 13 studied in-vivo and ex-vivo skin steady-state autofluorescence excitation and emission spectra and observed that both in basal cell carcinomas (BCC) and squamous cell carcinomas (SCC), the endogeneous fluorescence attributed to tryptophan residues was more intense in tumors than in normal skin. Their results showed that endogeneous fluorescence of non-melanoma skin cancers, excited in the UV region of the spectrum has characteristic features that are different from normal skin and may be exploited for non-invasive diagnostics and for the detection of tumor margins.…”