Capillary electrophoresis-mass spectrometry for targeted and untargeted analysis of the sub-5 kDa urine metabolome of patients with prostate or bladder cancer: A feasibility study

Targeted and untargeted analyses of the sub-5 kDa urine metabolome of genitourinary cancer patients (prostate and/or bladder) were performed without chemical derivatization using capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS). For targeted analysis, endogenous levels of sarcosine and 5 other amino acid metabolites implicated in the progression of prostate cancer were quantified in four patients and in a pooled urine sample from healthy volunteers. An untargeted analysis (m/z 50 to 850) of patient urine was performed using the same CE-ESI-MS system identifying over 400 distinct molecular features per patient. All patient urine samples were collected at prostatectomy/cystectomy via catheter. Patient urine samples were filtered by centrifugation, with endogenous sarcosine enriched by solid-phase extraction, and the processed samples loaded onto CE-ESI-MS for analysis. Diagnostic information, digital pathological slides, and tissue samples were collected and stored in a comprehensive biobanking database. The introduction of urine sample collection into the surgery workflow was facile and is a promising strategy for addressing the translational research challenge of moving smoothly from "chromatogram to nomogram".