CHEMOMETRICAL ANALYSIS OF ENDOMETRIAL TISSUE FLUORESCENCE SPECTRA A.Vaitkuviene a *, E.Auksorius a , D. Fuchs b , V.Gavriushin a a Vilnius University, Institute of Materials Science and Applied Research, b Innsbruck University, Institute of Medical Chemistry and Biochemistry, and Ludwig Boltzmann Institute of AIDS-Research. ABSTRACT An effort has been made to detect neopterin spectrum in fluorescence of premalignant endometrial tissue and to estimate the number of fluorophores naturally existing in the tissue with fluorescence present above the noise level. Endometrial Tissue fluorescence was measured in vitro by excitation with the third harmonic of Nd YAG laser. Multivariate curve resolution was used for testing neopterin presence in endometrial tissue. Fluorescence spectra of neopterin was measured and used as a target spectrum for testing. Seven factors – fluorescence of natural fluorophores of endometrial tissue were found to be present above the noise level in the overall autofluorescence. Neopterin concentration may be too low in endometrial tissue to make its fluorescence above the noise level because neopterin spectrum was not found to be among the spectra resolved by multivariate curve resolution. An intensity increase in the neopterin spectrum spectral region in hyperplastic endometrial samples might be associated with neopterin concentration increase. Keywords: Biomarker, Laser induced fluorescence spectroscopy, Multivariate curve resolution. 1. INTRODUCTION Diagnostic techniques based on optical spectroscopy have the potential to link the biochemical and morphological properties of tissues to individual patient care. If applied successfully, optical spectroscopy has the potential to represent an important step forward toward advances in diagnostic and therapeutic medical applications.Currently, one of the most widely explored applications of fluorescence spectroscopy is the detection of endoscopically invisible, early neoplastic growth in epithelial tissue sites. There are no effective diagnostic techniques for these early tissue transformations. If fluorescence spectroscopy can be applied successfully as a diagnostic technique in this clinical context, it may increase the potential for curative treatment and thus reduce complications. Fluorescence spectroscopy is ideally suited for this application because of its ability to examine tissue surfaces rather than tissue volumes, and its adaptability to an endoscopic device. Biological molecules that exhibit endogenous fluorescence are amino acids, structural proteins, enzymes and coenzymes, vitamins, lipids and porphyrins. Their excitation maxima lie in the range 250–450 nm, whereas their emission maxima lie in the range 280–700 nm [1]. The endogenous fluorophores that are speculated to play a role in transformations that occur with carcinogenesis are the amino acids tryptophan and tyrosine, the structural proteins collagen and elastin, the coenzymes NADH and FAD and porphyrins biological processes. * Correspondence: Women Clinics, Vilnius University, Saulėtekio al. 6 III 2040 Vilnius, Lithuania Laser Florence 2001: A Window on the Laser Medicine World, Leonardo Longo, Alfons G. Hofstetter MihaiI Lucian Pascu, Wilhelm R. A. Waidelich Editors Proceedings of SPIE Vol 4903 (2002) 240 © 2002 SPIE - 1605 - 7422/01/$15.00