Laser-induced flourescence (LIF) spectra of normal, benign and malignant breast tissue

Abstract

Aims (1) To demonstrate the efficacy of laser-induced fluorescence spectroscopy (LIF) in the discrimination of normal, benign and malignant breast tissue using histopathology as gold standard.(2) To develop a fibre optic probe using the data from the above mentioned method to diagnose breast malignancy in vivo. Methods Twenty-nine normal, 20 benign and 27 malignant specimens were excited at three to four sites by laser radiation at 325 nm after mounting on quartz plate. Results Emission spectral profiles of malignant, benign and normal tissue were as follows: Malignant tissue and benign tumours had higher intensity of collagen peak as compared to normal tissue. Higher content of total NAD(P)H, and bound NAD(P)H was seen in malignant tissue. Lower total NAD(P)H and increased free NAD(P)H was seen in benign tumours. Sharper 390 nm and weaker 460 nm peaks were characteristically seen in benign tissue. Discussion Endogenous fluorophores such as collagen/elastin and NAD(P)H cause autoflourescence. Intensities and ratios were assessed by spectra deconvolution. The increase in NAD(P)H concentration is due to shift of metabolism from aerobic to anaerobic and increase in mitochondrial metabolism. Increased bound NAD(P)H in malignancy may be due to increased binding by overexpressed proteins secreted by tumour cells.