###### Abstract  
The results of using nonstationary high-resolution THz spectroscopy for detecting a characteristic set of metabolites of thermal decomposition products of urine from prostate cancer patients, aimed at identifying specific markers, are presented. Studies of the composition of biological fluid in prostate cancer were carried out using 12 urine samples from cancer patients and 4 samples from conditionally healthy volunteers. Differences in the composition and content of substances in the urine samples of cancer patients compared to the urine of conditionally healthy volunteers were identified, which allows preliminary conclusions to be drawn about substances promising for use as markers of prostate cancer in urine. The presented approach is promising for developing a method for noninvasive study of the composition of biological fluids, which makes it possible to identify metabolite markers of various pathologies and diseases. THz high-resolution spectroscopy; prostate cancer; urina; prostate-specific antigen; thermal decomposition; metabolite +
Footnote †: journal: Medical Medical and Biological Agency of Russia,  
liquid chromatography, including in combination with mass spectrometry, or spectroscopic methods are used for analysis of metabolites. The chromatography-mass spectrometry method is as follows: Passing through a chromatograph, the sample is separated into components, and the mass spectrometer is responsible for their identification and analysis. Depending on the characteristics of the composition under study and the requirements for the accuracy of the result, one of two methods is used, either high-precision liquid chromatography or gas chromatography with mass spectrometric detection. The disadvantages of chromatographic methods include the impossibility of simultaneous study of both polar and non-polar substances. This depends on the choice of chromatographic column, as well as the difficulty of sample preparation for several samples. The main disadvantage of mass spectrometry is that the method is destructive, i.e., it is not the substance itself that is studied, but the products of its transformation. Spectroscopic methods (e.g., nuclear magnetic resonance (NMR), spectroscopies of IR or THz ranges, etc.) have more advantages over chromatography-mass spectrometry methods. NMR is a non-destructive method, which makes it possible to carry out repeated experiments with the same sample. NMR requires minimal sample preparation and can detect even previously unknown compounds. Disadvantages of NMR include the difficulty of detecting compounds with high molecular weight (for example, long chains of fats) and the overlap of peaks corresponding to different compounds on each other. Combining NMR with other methods, for example, mass spectroscopy, will improve the efficiency of metabolite identification. Nuclear magnetic resonance will make it possible to find unknown compounds, which can then be targeted in other samples using mass spectroscopy. Analysis of data in the literature allows the state of the art in the area of analysis of metabolites in urine to be highlighted. Urine should be analyzed, first of all, from a human body in a healthy state, as well as from a body in a diseased state, in particular having prostate cancer, using various physical methods. The study of the urine of living organisms (humans, animals) aimed at identifying the sets of metabolites characterizing a healthy organism [1], the influence of physical activity [2], and the sets characterizing pathologies, is carried out primarily by chromatographic and some spectroscopic methods. Using high-resolution 1H nuclear magnetic resonance spectroscopy, variations in the composition of urine samples of two groups were investigated: a group of 60 healthy men and women for 30 days and a group of 25 guinea pigs of similar genetics, diet, and living environment [3].