Discovery of Novel Bladder Cancer Biomarkers by Comparative Urine Proteomics Using iTRAQ Technology

Abstract

A urine sample preparation workflow for the iTRAQ (isobaric tag for relative and absolute quantitation) technique was established. The reproducibility of this platform was evaluated and applied to discover proteins with differential levels between pooled urine samples from nontumor controls and three bladder cancer patient subgroups with different grades/stages (a total of 14 controls and 23 cancer cases in two multiplex iTRAQ runs). Combining the results of two independent clinical sample sets, a total of 638 urine proteins were identified. Among them, 55 proteins consistently showed >2-fold differences in both sample sets. Western blot analyses of individual urine samples confirmed that the levels of apolipoprotein A-I (APOA1), apolipoprotein A-II, heparin cofactor 2 precursor and peroxiredoxin-2 were significantly elevated in bladder cancer urine specimens (n = 25-74). Finally, we quantified APOA1 in a number of urine samples using a commercial ELISA and confirmed again its potential value for diagnosis (n = 126, 94.6% sensitivity and 92.0% specificity at a cutoff value of 11.16 ng/mL) and early detection (n = 71, 83.8% sensitivity and 94.0% specificity). Collectively, our results provide the first iTRAQ-based quantitative profile of bladder cancer urine proteins and represent a valuable resource for the discovery of bladder cancer markers.

Bladder Cancer Determination Via Two Urinary Metabolites: A Biomarker Pattern Approach

“…The success of BC treatment depends mainly on early detection (1). Currently, cystoscopy and urinary cytology are the standard diagnostic tools for BC (2,3). However, cystoscopy is invasive and labor-intensive, and carcinoma in situ (CIS) of the bladder may easily be missed, given the similarity in appearance of red mucosal spots in inflammatory lesions and CIS of the bladder (4).…”

Microdevices for Non-Invasive Detection of Bladder Cancer

“…In 2013, a point-of-care device was presented for bladder cancer diagnosis based on magnetic microbead capture of apolipoprotein A1 (APOA1) [77], which has been demonstrated to be present at elevated concentrations in the urine of bladder cancer patients [99][100][101] (Figure 4). Magnetic microbeads bound to APOA1-targeted antibodies were incubated with a urine sample to allow binding of APOA1 to the microbead.…”

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

“…Under normal conditions, urine contains proteins originating from the blood and kidneys [134][135][136][137][138][139], making urine a good source for analysis of diseases affecting the kidney or the urogenital tract; such as kidney failure resulting from high blood pressure and diabetic nephropathy [140,141], prostate cancer [142,143], polycystic kidney disease [144], kidney chronic allograft dysfunction [145], chronic allograft nephropathy [146], congenital obstructive nephropathy [147], lupus nephritis [148], urolithiasis [149], in addition to urinary, renal and bladder cancer [150][151][152][153][154][155][156][157][158][159][160][161]. Besides urogenital and kidney dysfunctions, urinary proteomics has a great potential in biomarker studies of coronary artery atherosclerosis [162,163], obstructive sleep apnea [164], ovarian cancer [165], breast cancer [166] and sepsis [167,168].…”

“…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].…”