Determination of amino acids in urine of patients with prostate cancer and benign prostate growth Wiktor D. Sroka a , Berin A. Boughton e , Priyanka Reddy e , Ute Roessner e , Piotr Slupski c , Piotr Jarzemski c , Anita Dąbrowska b , Michal J. Markuszewski d and Michal P. Marszall a Prostate cancer is the leading type of cancer diagnosed in men. Serum prostate-specific antigen levels and digital rectal exam are far from perfect when it comes to differentiation of patients with prostate cancer and benign prostatic hyperplasia. In this study, we attempt to determine whether amino acids can be used as prostate cancer biomarkers. Concentrations of derivatized amino acids and amines were quantified by liquid chromatography tandem mass spectrometry. A total of 100 urine samples from the two groups including samples provided before and after prostate massage were examined quantitatively for amino acid and amine concentrations with 50 urine samples collected from cancer patients and 50 samples from patients diagnosed with benign prostatic hyperplasia. Arginine, homoserine, and proline were more abundant in urine samples of cancer patients compared with arginine, homoserine, and proline levels determined in urine collected from patients with benign growth. We also show that sarcosine is not a definitive indicator of prostate cancer when analyzed in urine samples collected either before or after prostate massage. European Journal of Cancer Prevention 00:000–000 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. European Journal of Cancer Prevention 2016, 00:000–000 Keywords: amino acids, benign prostatic hyperplasia, biomarker, cancer, prostate Departments of a Medicinal Chemistry, b Theoretical Foundations of Biomedical Sciences and Medical Informatics, c Department of Urology, Jan Biziel Hospital, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, d Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gdansk, Poland and e Metabolomics Australia, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia Correspondence to Michal P. Marszall, PhD, Department of Medicinal Chemistry, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, ul. Jurasza 2, 85-094 Bydgoszcz, Poland Tel: + 48 52 585 3540; fax: + 48 52 585 3804; e-mail: mmars@cm.umk.pl Received 15 September 2015 Accepted 7 February 2016 Introduction Prostate cancer (PCa) is the second most common cause of cancer-related death and leading type of cancer diag- nosed in men. Currently, for screening purposes, serum prostate-specific antigen (PSA) levels and digital rectal examination are used to determine whether a patient presents with PCa. PSA levels can be useful in differ- entiating healthy and sick patients, but it needs to be noted that the sensitivity and specificity of this test are poor. Although PSA testing can diagnose more men with PCa, PSA is not a perfect biomarker. PSA is specific to the prostate gland, not to PCa; patients diagnosed for example with benign prostatic hyperplasia (BPH) can also present with elevated serum PSA levels (Lilja et al., 2008; Wolf et al., 2010). Monitoring changes in certain metabolites may be a way to detect early stages of carcinogenesis, predict cancer stage, or monitor the treatment response. The new bio- marker may improve the diagnostic process by helping physicians to more accurately diagnose patients and also improve a patient’s comfort during the procedure by reducing the number of invasive procedures (Birkemeyer et al., 2005; Denkert et al., 2006; Wang et al., 2010; Serkova et al., 2011). The aims of our research were to measure changes in amine and amino acid concentrations in urine from samples collected in the morning, before and after pros- tate massage, identify and quantify a number of amino acids in urine with the aim of testing the use of sarcosine as a definitive marker of PCa, or to find an improved biomarker (Sreekumar et al., 2009). Methods A total of 50 individuals were recruited into two main groups of patients – a cancer group of 25 patients diag- nosed with PCa qualifying for radical prostatectomy and a second BPH group of 25 patients qualifying for transur- ethral resection of the prostate with no evidence of malignancy, but diagnosed with BPH. Amino acids and biogenic amines were measured according to Boughton et al. (2011). Concentrations of derivatized amino acids were quantified by liquid chromatography mass spectro- metry using an Agilent 1200 LC-system coupled to an Agilent 6410 ESI-QqQ-MS (Santa Clara, California, USA) by comparison with external calibration curves. More detailed information can be found in the Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (www.eurjcancerprev.com). Short paper 1 0959-8278 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/CEJ.0000000000000248 Copyright r 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.