The objective of this study was to assess the diagnostic potential of synchronous fluorescence (SF) spectroscopy (SFS) technique for the detection and characterization of normal and different malignancy stages of moderately differentiated squamous cell carcinoma (MDSCC), poorly differentiated squamous cell carcinoma (PDSCC) cervical tissues. SF spectra were measured from 45 biopsies from 30 patients in vitro. Characteristic, highly resolved peaks and significant spectral differences between normal and MDSCC, PDSCC cervical tissues were obtained. Nine potential ratios were calculated and used as input variables for a discriminant analysis across different groups. The potentiality of the SFS technique was estimated by two discriminant analyses. Discriminant analysis I performed across normal and abnormal (including MDSCC and PDSCC) cervical tissues classified as 100% both original and the cross-validated grouped cases. In discriminant analysis II performed across the three groups, normal, MDSCC and PDSCC, 100% of both original and the cross-validated grouped cases were correctly classified. Using the SFS technique, one can obtain all the key biochemical markers such as tryptophan, collagen, hemoglobin, reduced form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide in a single scan and hence they can be targeted as tumor markers in the detection of normal from abnormal cervical tissues.

Fluorescence excitation spectroscopy (FES) is an emerging approach to cancer detection. The goal of this pilot study is to evaluate the diagnostic potential of FES technique for the detection and characterization of normal and cancerous oral lesions in vivo. Fluorescence excitation (FE) spectra from oral mucosa were recorded in the spectral range of 340 to 600 nm at 635 nm emission using a fiberoptic probe spectrofluorometer to obtain spectra from the buccal mucosa of 30 sites of 15 healthy volunteers and 15 sites of 10 cancerous patients. Significant FE spectral differences were observed between normal and well differentiated squamous cell carcinoma (WDSCC) oral lesions. The FE spectra of healthy volunteers consists of a broad emission band around 440 to 470 nm, whereas in WDSCC lesions, a new primary peak was seen at 410 nm with secondary peaks observed at 505, 540, and 580 nm due to the accumulation of porphyrins in oral lesions. The FE spectral bands of the WDSCC lesions resemble the typical absorption spectra of a porphyrin. Three potential ratios (I410/I505, I410/I540, and I410/I580) were calculated from the FE spectra and used as input variables for a stepwise linear discriminant analysis (SLDA) for normal and WDSCC groups. Leave-one-out (LOO) method of cross-validation was performed to check the reliability on spectral data for tissue characterization. The diagnostic sensitivity and specificity were determined for normal and WDSCC lesions from the scatter plot of the discriminant function scores. It was observed that diagnostic algorithm based on discriminant function scores obtained by SLDA-LOO method was able to distinguish WDSCC from normal lesions with a sensitivity of 100% and specificity of 100%. Results of the pilot study demonstrate that the FE spectral changes due to porphyrin have a good diagnostic potential; therefore, porphyrin can be used as a native tumor marker.

Stokes shift spectroscopy (S3) is an emerging approach toward cancer detection. The goal of this paper is to evaluate the diagnostic potential of the S3 technique for the detection and characterization of normal and cancerous prostate tissues. Pairs of cancerous and normal prostate tissue samples were taken from each of eight patients. Stokes shift spectra were measured by simultaneously scanning both the excitation and emission wavelengths while keeping a fixed wavelength interval Δλ=20  nm between them. The salient features of this technique are the highly resolved emission peaks and significant spectral differences between the normal and cancerous prostate tissues, as observed in the wavelength region of 250 to 600 nm. The Stokes shift spectra of cancerous and normal prostate tissues revealed distinct peaks around 300, 345, 440, and 510 nm, which are attributed to tryptophan, collagen, NADH, and flavin, respectively. To quantify the spectral differences between the normal and cancerous prostate tissues, two spectral ratios were computed. The findings revealed that both ratio parameters R1=I297/I345 and R2=I307/I345 were excellent diagnostic ratio parameters giving 100% specificity and 100% sensitivity for distinguishing cancerous tissue from the normal tissue. Our results demonstrate that S3 is a sensitive and specific technique for detecting cancerous prostate tissue.

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Stokes Shift (SS) Spectroscopy (SSS) of normal and abnormal breast and prostate tissues were studied. SS spectra is measured by simultaneously scanning both the excitation and emission wavelengths while keeping a fixed wavelength interval of Δλ = 20 nm. Characteristic, highly resolved peaks and significant spectral differences between normal and different pathological tissues of breast and prostate tissues were observed. The SS spectra of normal and different pathological breast and prostate tissues show the distinct peaks around 300, 350, 450, 500 and 600 nm may be attributed to tryptophan, collagen, NADH, flavin and porphyrin, respectively. Results of the current study demonstrate that the SS spectral changes due to tryptophan, collagen, hemoglobin, NADH, FAD and porphyrin have good diagnostic potential; therefore can be targeted as native tumor markers.