Detection of Energy Metabolism Level in Cancer Patients by Fluorescence Emission from Serum

Changes in fluorescence emission of the serum from patients with various cancers are characterized. The measurement of fluorescence emission of serum in the UVvisible range allows by estimation of NAD(P)H levels to monitor the alterations in energy metabolism, resulting from changes in the level of coenzymes in serum associated with neoplastic diseases. Introduction Over the past years, f luorescence spectroscopy, a method that is several orders of magnitude more sensitive and more selective than absorption-based techniques, has been used to characterize physicochemical properties of biomolecules that exhibit fluorescence in cells, tissues and in serum. Consequently, fluorescence spectroscopy of biomolecules has been used to characterize cell metabolic pathways and to discriminate pathological conditions of cells, tissues and organs from their normal state. Native fluorescence emission and excitation spectra of virus-infected human keratinocytes, carcinoma cells, and normal human keratinocytes were shown to differ in the intracellular metabolic state of reduced nicotinamide adenine dinucleotide (NADH). It was suggested that the observed differences were due to an increased proportion of bound mitochondrial NADH in the cancer and virus-infected cells. In the field of diagnostic oncology, studies indicate that native fluorescence properties of tissue can be used to distinguish normal from malignant conditions in breast, cervix, colon, and bronchus samples. Measurements of emission intensity or spectral ratios of emission intensity (for example at 340 and 440nm) under UV light excitation were shown to statistically differentiate normal from malignant tissues. In a series of studies, a fluorometric screening method was established for the analysis of the emission of serum to detect patients with tumors and chronic diseases. The ultraviolet fluorescence emission spectra of serum (mostly protein content) from healthy persons and of serum from cancer patients, frequently exhibited different curve shapes. In addition to the complexity of observing differences in emission from different fractions in serum, fluorescence of native serum can be attributed to a variety of molecules including tryptophan, tyrosine, phenylalanine, NADH, pyridoxal phosphate, bilirubin, flavin-adenine dinucleotide (FAD) and others. The fluorescence associated with these molecules is defined by their concentration and distribution as well as the photo-physicochemical properties of their environment. We have begun a study of detecting metabolic dysfunctions by fluorescence in human serum. Our results reported here for cancer allow us to differentiate normal from abnormal metabolic behavior in human functioning and may lead to improvement of human functioning through detection of such disorders. Experimental Procedures Preparation of Samples Baseline, normal blood samples were obtained from healthy staff volunteers. The experimental samples of serum were obtained from patients, which were clinically Detection of Energy Metabolism Level in Cancer Patients by Fluorescence