Pilot study of capillary electrophoresis coupled to mass spectrometry as a tool to define potential prostate cancer biomarkers in urine

Abstract

We describe the use of capillary electrophoresis (CE) coupled with mass spectrometry (MS) to identify single polypeptides and patterns of polypeptides specific for prostate cancer (CaP) in human urine. Using improved sample preparation methods that enable enhanced comparability between different samples, we examined samples from 47 patients who underwent prostate biopsy. Of this group, 21 patients had benign pathology and 26 with CaP, and these were used to define potential biomarkers, which allow discrimination between these two states. In addition, CE-MS data from these 47 urine samples were compared to that of 41 young men (control) without known or suspected clinical CaP to further confirm the polypeptides indicative for CaP. Upon crossvalidation of the same samples, several polypeptides were selected that enabled correct classification of the CaP patients with 92% sensitivity and 96% specificity. We then examined an additional 474 samples from patients with renal disease enrolled in other studies and found that 14 (3%) had polypeptides suggestive of CaP possibly indicating that they harbor clinical CaP. In conclusion, this early pilot study suggests that CE-MS of urine warrants further investigation as a tool that can identify putative biomarkers for CaP.

A Distinct Urinary Biomarker Pattern Characteristic of Female Fabry Patients That Mirrors Response to Enzyme Replacement Therapy

“…Migration time and ion signal intensity (amplitude) were normalized using internal polypeptide standards [45], [46]. For the identification of potential biomarkers, the reported p-values were calculated using the Wilcoxon Rank-Sum test followed by adjustment for multiple testing using the method described by Benjamini and Hochberg [47].…”

Urinary Proteomics in Diabetes and CKD

“…3 In addition, the migration time and ion signal intensity (amplitude) were normalized using internal polypeptide standards as described in detail previously. 25 This approach results in superior comparability of the data sets as compared with normalization of the signal intensity to urinary creatinine or total protein content, because especially the latter will give poor results in patients with proteinuria. Each polypeptide is characterized by its molecular mass (kD), normalized migration time (min), and normalized signal intensity as the measure for relative abundance.…”

Quantitative body fluid proteomics in medicine — A focus on minimal invasiveness

“…This can be compensated for by standardization based on urinary creatinine [169] or urinary housekeeping peptides, which are present almost ubiquitously in human urine independently of age, sex, health, or drug administration [170]. Details on urine sample preparation have already been discussed in some recently published reviews [171][172][173][174][175].…”

“…Urine proteome analysis may potentially unravel markers for cancers of urogenital or systemic origin including bladder [150][151][152][153][154]156,157,160,161], prostate [170], renal [158,159], breast [166] and ovarian cancers [165] (Table 7). There has been an increasing interest in developing urine biomarkers for the detection of renal allograft rejection as an alternative to percutaneous needle biopsy, which is costly and associated with significant patient morbidity and mortality [79].…”