Urine cytology and urine-based markers for bladder urothelial carcinoma detection and monitoring: developments and future prospects

Urinary biomarkers in bladder cancer: where do we stand?

PURPOSE OF REVIEW

To provide a current comprehensive review of the available urinary biomarkers for the detection and surveillance of bladder cancer.

RECENT FINDINGS

The limitations of urine cytology and invasive nature of cystoscopic evaluation have led to a growing search for an ideal, cost-effective biomarker with acceptable sensitivity and specificity. Current FDA approved biomarkers such as UroVysion fluorescent in situ hybridization, Immunocyt, and nuclear matrix protein 22 do not have the specificity, and thus positive predictive value to warrant their cost as a routine adjunct or replacement for cystoscopy. Several promising commercially available assays such as Cxbladder, Assure MDx, and Xpert BC may perform better than cytology in select populations. Novel genomic, epigenetic, inflammatory, and metabolomic-based assays are being analyzed as potential urinary biomarkers.

SUMMARY

Urinary biomarkers with high sensitivity and specificity are an unmet need in bladder cancer. Several new assays may meet these criteria and future research may justify use in clinical practice.

Prognostic relevance of positive urine markers in patients with negative cystoscopy during surveillance of bladder cancer

Background

The role of urine markers in the surveillance of patients with non-muscle invasive bladder cancer (NMIBC) is discussed extensively. In case of negative cystoscopy the additional prognostic value of these markers has not been clearly defined yet. The present study is the first systematic approach to directly compare the ability of a urine marker panel to predict the risk of recurrence and progression in bladder cancer (BC) patients with no evidence of relapse during surveillance for NMIBC.

Methods

One hundred fourteen patients who underwent urine marker testing during surveillance for NMIBC and who had no evidence of BC recurrence were included. For all patients cytology, Fluorescence-in-situ-hybridization (FISH), immunocytology (uCyt+) and Nuclear matrix protein 22 enzyme-linked immunosorbent assay (NMP22) were performed. All patients completed at least 24 months of endoscopic and clinical follow-up of after inclusion.

Results

Within 24 months of follow-up, 38 (33.0%) patients experienced disease recurrence and 11 (9.8%) progression. Recurrence rates in patients with positive vs. negative cytology, FISH, uCyt+ and NMP22 were 52.6% vs. 21.9% (HR = 3.9; 95% CI 1.75-9.2; p < 0.001), 47.6% vs. 25.0% (HR 2.7; 1.2-6.2; p = 0.01), 43.8% vs. 22.4% (HR 3.3; 1.5-7.6; p = 0.003) and 43.8% vs. 16.7% (HR 4.2; 1.7-10.8; p = 0.001). In patients with negative cytology, a positive NMP22 test was associated with a shorter time to recurrence (p = 0.01), whereas FISH or uCyt+ were not predictive of recurrence in these patients. In the group of patients with negative cytology and negative NMP22, only 13.5% and 5.4% developed recurrence and progression after 24 months.

Conclusions

Patients with positive urine markers at time of negative cystoscopy are at increased risk of recurrence and progression. In patients with negative cytology, only NMP22 is predictive for recurrence. Patients with negative marker combinations including NMP22 harbour a low risk of recurrence. Therefore, the endoscopic follow-up regimen may be attenuated in this group of patients.

An analysis of the impact of pre-analytical factors on the urine proteome: Sample processing time, temperature, and proteolysis

Purpose

We have examined the impact of sample processing time delay, temperature, and the addition of protease inhibitors (PIs) on the urinary proteome and peptidome, an important aspect of biomarker studies.

Experimental design

Ten urine samples from patients with varying pathologies were each divided and PIs added to one‐half, with aliquots of each then processed and frozen immediately, or after a delay of 6 h at 4°C or room temperature (20–22°C), effectively yielding 60 samples in total. Samples were then analyzed by 2D‐PAGE, SELDI‐TOF‐MS, and immunoassay.

Results

Interindividual variability in profiles was the dominant feature in all analyses. Minimal changes were observed by 2D‐PAGE as a result of delay in processing, temperature, or PIs and no changes were seen in IgG, albumin, β₂‐microglobulin, or α₁‐microglobulin measured by immunoassay. Analysis of peptides showed clustering of some samples by presence/absence of PIs but the extent was very patient‐dependent with most samples showing minimal effects.

Conclusions and clinical relevance

The extent of processing‐induced changes and the benefit of PI addition are patient‐ and sample‐dependent. A consistent processing methodology is essential within a study to avoid any confounding of the results.