title: Monitoring potential prostate cancer biomarkers in urine by capillary electrophoresis-tandem mass spectrometry.
abstract: Current prostate cancer (PCa) diagnosis based on prostate-specific antigen (PSA) has been gradually losing its credibility over the last decade due to contradictory results in published literature and clinical practice. Recently, a group of potential PCa biomarkers in urine, particularly sarcosine, was found to increase significantly as the cancer progressed to metastasis. We report a simple, robust, and reproducible CE-ESI-MS/MS method for the determination of sarcosine and other representative potential biomarkers in pooled urine. The pooled urine was obtained from 20 healthy adult volunteers between the ages of 23-30 years old. A solid phase extraction (SPE) technique was optimized for maximum recovery of sarcosine. With no derivatization step, excellent resolution between sarcosine and its isomers (α-alanine and β-alanine) was achieved. A separate non-SPE method was also developed for quantitative determination of highly concentrated urinary metabolites. CE separation was performed on a positively-charged, polyethyleneimine (PEI)-coated capillary using 0.4-2% formic acid in 50% methanol. Precision for intra- and inter-day standard addition calibration of sarcosine were found to be within 15%, whereas intra-day precisions for the rest of the metabolites varied from 0.03 to 13.4%. Acceptable intra-day and inter-day accuracies, ranging from 80 to 124%, were obtained for sarcosine and the other metabolites.
authors: Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
authors: Laiel C
authors: LC
authors: Soliman
authors: Yu
authors: Y
authors: Hui
authors: Amitha K
authors: AK
authors: Hewavitharana
authors: David D Y
authors: DD
authors: Chen
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007536:Isomerism; D008297:Male; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000652:urine; D012521:Sarcosine / Q000737:chemistry / Q000652:urine*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D012521:Sarcosine