DETECTING RETINOIC ACID-INDUCED BIOCHEMICAL-ALTERATIONS IN SQUAMOUS-CELL CARCINOMA USING INTRINSIC FLUORESCENCE SPECTROSCOPY

Intrinsic fluorescence spectroscopy offers a new method for diagnosing head and neck cancers. By establishing a unique spectral fingerprint for benign tissue, one can readily identify subtle changes in tissue b ased on altered spectral patterns. The authors applied this technology to a multicellular tumor spheroid (MTS) model and obtained baseline s pectral data. A cohort of MTS was treated with the chemopreventive age nt retinoic acid (RA) to determine its effect on tumor cells. Excitati on and emission spectroscopy were performed on the samples. Spectrosco pic scans demonstrated consistently that RA-treated MTS exhibit a decr ease in the peak associated with reduced nicotinamide-adenine dinucleo tide (NADH) and an increase in the peaks associated with flavins, tryp tophan, and cytokeratins when compared to controls. These findings are suggestive of alterations in cellular electron transport, an increase in proteins incorporating tryptophan, and a decrease in adenosine tri phosphate (ATP) in the RA-treated cells. A discussion of the potential clinical applications of intrinsic fluorescence spectroscopy is inclu ded.