The current role of circulating biomarkers in non-muscle invasive bladder cancer

Molecular characterization and functional roles of circulating cell-free extrachromosomal circular DNA

Circular DNA segments isolated from chromosomes are known as extrachromosomal circular DNA (eccDNA). Its distinct structure and characteristics, along with the variations observed in different disease states, makes it a promising biomarker. Recent studies have revealed the presence of eccDNAs in body fluids, indicating their involvement in various biological functions. This finding opens up avenues for utilizing eccDNAs as convenient and real-time biomarkers for disease diagnosis, treatment monitoring, and prognosis assessment through noninvasive analysis of body fluids. In this comprehensive review, we focused on elucidating the size profiles, potential mechanisms of formation and clearance, detection methods, and potential clinical applications of eccDNAs. We aimed to provide a valuable reference resource for future research in this field.

Elevated T-cell Exhaustion and Urinary Tumor DNA Levels Are Associated with Bacillus Calmette-Guérin Failure in Patients with Non–muscle-invasive Bladder Cancer

BACKGROUND

The functional status of immune cells in the tumor microenvironment and tumor characteristics may explain bacillus Calmette-Guérin (BCG) failure in high-risk non-muscle-invasive bladder cancer (NMIBC).

OBJECTIVE

To characterize molecular correlates of post-BCG high-grade (HG) recurrence using multiomics analysis.

DESIGN, SETTING, AND PARTICIPANTS

Patients with BCG-treated NMIBC (n = 156) were included in the study. Metachronous tumors were analyzed using RNA sequencing (n = 170) and whole-exome sequencing (n = 195). Urine samples were analyzed for immuno-oncology-related proteins (n = 190) and tumor-derived DNA (tdDNA; n = 187).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was post-BCG HG recurrence. Cox regression and Wilcoxon rank-sum, t, and Fisher's exact tests were used for analyses.

RESULTS AND LIMITATIONS

BCG induced activation of the immune system regardless of clinical response; however, immunoinhibitory proteins were observed in the urine of patients with post-BCG HG recurrence (CD70, PD1, CD5). Post-BCG HG recurrence was associated with post-BCG T-cell exhaustion (p = 0.002). Pre-BCG tumors from patients with post-BCG T-cell exhaustion had high expression of genes related to cell division and immune function. A high predicted post-BCG exhaustion score for pre-BCG tumors was associated with worse post-BCG HG recurrence-free survival (HGRFS; p = 0.002). This was validated in independent cohorts. Pre-BCG class 2a and 2b tumors (UROMOL2021 scheme) were associated with worse post-BCG HGRFS (p = 0.015). Post-BCG exhaustion was observed in patients with high pre-BCG neoantigen load (p = 0.017) and MUC4 mutations (p = 0.002). Finally, the absence of post-BCG tdDNA clearance identified patients at high risk of recurrence (p = 0.018). The retrospective design and partial overlap for analyses are study limitations.

CONCLUSIONS

Post-BCG HG recurrence may be caused by T-cell exhaustion. Tumor subtype and pre-BCG tumor characteristics may identify patients at high risk of post-BCG HG recurrence. Urinary measurements have potential for real-time assessment of treatment response.

PATIENT SUMMARY

A dysfunctional immune response to bacillus Calmette-Guérin (BCG) therapy may explain high-grade recurrences of bladder cancer.

Circle-Seq reveals genomic and disease-specific hallmarks in urinary cell-free extrachromosomal circular DNAs

BACKGROUND

Extrachromosomal circular deoxyribonucleic acid (eccDNA) is evolving as a valuable biomarker, while little is known about its presence in urine.

METHODS

Here, we report the discovery and analysis of urinary cell-free eccDNAs (ucf-eccDNAs) in healthy controls and patients with advanced chronic kidney disease (CKD) by Circle-Seq.

RESULTS

Millions of unique ucf-eccDNAs were identified and comprehensively characterised. The ucf-eccDNAs are GC-rich. Most ucf-eccDNAs are less than 1000 bp and are enriched in four pronounced peaks at 207, 358, 553 and 732 bp. Analysis of the genomic distribution of ucf-eccDNAs shows that eccDNAs are found on all chromosomes but enriched on chromosomes 17, 19 and 20 with a high density of protein-coding genes, CpG islands, short interspersed transposable elements (SINEs) and simple repeat elements. Analysis of eccDNA junction sequences further suggests that microhomology and palindromic repeats might be involved in eccDNA formation. The ucf-eccDNAs in CKD patients are significantly higher than those in healthy controls. Moreover, eccDNA with miRNA genes is highly enriched in CKD ucf-eccDNA.

CONCLUSIONS

This work discovers and provides the first deep characterisation of ucf-eccDNAs and suggests ucf-eccDNA as a valuable noninnvasive biomarker for urogenital disorder diagnosis and monitoring.

Prognostic value of the systemic immune-inflammation index in non-muscle invasive bladder cancer

Purpose

We assessed the prognostic value of systemic immune-inflammation index (SII) to refine risk stratification of the heterogeneous spectrum of patients with non-muscle-invasive bladder cancer (NMIBC)

Methods

In this multi-institutional cohort, preoperative blood-based SII was retrospectively assessed in 1117 patients with NMIBC who underwent transurethral resection of bladder (TURB) between 1996 and 2007. The optimal cut-off value of SII was determined as 580 using the best Youden index. Cox regression analyses were performed. The concordance index (C-index) and decision curve analysis (DCA) were used to assess the discrimination of the predictive models.

Results

Overall, 309 (28%) patients had high SII. On multivariable analyses, high SII was significantly associated with worse PFS (hazard ratio [HR] 1.84; 95% confidence interval [CI] 1.23–2.77; P = 0.003) and CSS (HR 2.53; 95% CI 1.42–4.48; P = 0.001). Subgroup analyses, according to the European Association of Urology guidelines, demonstrated the main prognostic impact of high SII, with regards to PFS (HR 3.39; 95%CI 1.57–7.31; P = 0.002) and CSS (HR 4.93; 95% CI 1.70–14.3; P = 0.005), in patients with intermediate-risk group; addition of SII to the standard predictive model improved its discrimination ability both on C-index (6% and 12%, respectively) and DCA. In exploratory intergroup analyses of patients with intermediate-risk, the improved discrimination ability was retained the prediction of PFS and CSS.

Conclusion

Preoperative SII seems to identify NMIBC patients who have a worse disease and prognosis. Such easily available and cheap standard biomarkers may help refine the decision-making process regarding adjuvant treatment in patients with intermediate-risk NMIBC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-021-03740-3.

Biomarkers for Precision Urothelial Carcinoma Diagnosis: Current Approaches and the Application of Single-Cell Technologies

Simple Summary

Urothelial carcinoma (UC) is the most frequently diagnosed cancer of the urinary tract and is ranked the sixth most diagnosed cancer in men worldwide. About 70–75% of newly diagnosed UCs are non-invasive or low grade. Different tests such as urine cytology and cystoscopy are used to detect UC. If abnormal tissue is found during cystoscopy, then a biopsy will be performed. Cytology has low sensitivity for low-grade cancer while cystoscopy is invasive and costly. Detecting UC early improves the chances of treatment success. Therefore, many researchers have painstakingly identified urine biological markers for non-invasive UC diagnosis. In this review, we summarize some of the latest and most promising biological markers (including FDA-approved and investigational markers). We also discuss some new technologies that can aid research efforts in biological marker discovery for early UC detection.

Abstract

Urothelial carcinoma (UC) is the most frequent malignancy of the urinary system and is ranked the sixth most diagnosed cancer in men worldwide. Around 70–75% of newly diagnosed UC manifests as the non-muscle invasive bladder cancer (NMIBC) subtype, which can be treated by a transurethral resection of the tumor. However, patients require life-long monitoring due to its high rate of recurrence. The current gold standard for UC diagnosis, prognosis, and disease surveillance relies on a combination of cytology and cystoscopy, which is invasive, costly, and associated with comorbidities. Hence, there is considerable interest in the development of highly specific and sensitive urinary biomarkers for the non-invasive early detection of UC. In this review, we assess the performance of current diagnostic assays for UC and highlight some of the most promising biomarkers investigated to date. We also highlight some of the recent advances in single-cell technologies that may offer a paradigm shift in the field of UC biomarker discovery and precision diagnostics.

Copy number variations in primary tumor, serum and lymph node metastasis of bladder cancer patients treated with radical cystectomy

The aim of the present study was to analyze copy number variations (CNV) of multiple oncogenes and tumor suppressor genes in genomic DNA from primary tumor tissue, lymph node metastasis and cell-free DNA (cfDNA) from serum of 72 urothelial carcinoma of bladder (UCB) patients treated with radical cystectomy (RC), using multiplex ligation-dependent probe amplification (MLPA). We hypothesized that primary tumor and lymph node metastasis show similar CNV profiles, and CNV are more present in lymph node metastasis compared to primary tumor tissue. Samples from 43 (59.7%) patients could be analyzed. In total, 35 (83%), 26 (68%) and 8 (42%) patients had CNV in primary tumor, serum and lymph node metastasis, respectively. MYC, CCND1, ERBB2 and CCNE1 displayed the most frequent amplifications. In particular, CNV in ERBB2 was associated with aggressive tumor characteristics. CNV in both ERBB2 and TOP2A were risk factors for disease recurrence. The current findings show that CNV are present in various oncogenes and tumor suppressor genes in genomic DNA from primary tumor, lymph node metastasis and cfDNA from serum. CNV were more present in genomic DNA from primary tumor tissue compared to cfDNA from serum and genomic DNA from lymph node metastasis. Patients with CNV in ERBB2 and TOP2A are at increased risk for disease recurrence following RC. Further studies are necessary to validate, whether these genes may represent promising candidates for targeted-therapy.

Biomarkers predicting oncological outcomes of high-risk non-muscle-invasive bladder cancer

INTRODUCTION

The European Organization for Research and Treatment of Cancer (EORTC) and the Spanish Urological Club for Oncological Treatment (CUETO) scoring systems show limited accuracy for the prediction of disease recurrence and progression of non-muscle-invasive bladder cancer (NMIBC). This aspect is even more relevant in the category of HR NMIBC. Biomarkers might potentially help to further categorize the outcomes of these patients. Therefore, we sought to review the evidence available on tissue-based, urinary, and serum biomarkers for the prediction of recurrence, progression, and survival in HR NMIBC.

EVIDENCE ACQUISITION

A systematic literature review without time restrictions was performed using PubMed/EMBASE, Web of Science, SCOPUS, and the Cochrane Libraries. The search was filtered for articles in the English, Italian, German, French, and Spanish languages, involving patients with more than 18 years of age. Relevant papers on tissue-based, serum and urinary biomarkers related to the prediction of oncological outcomes for high-risk bladder cancer patients were included in the analyses.

EVIDENCE SYNTHESIS

Overall, 71 studies were eligible for inclusion in this review. The majority of the investigations performed so far focused on immunohistochemical analyses on tumoral tissue. Overall, p53 was the most studied biomarker, but results regarding its prognostic and predictive role were contradictory. Ki67 seems to be a promising biomarker in the prediction of recurrence. Recently, PD-L1 has been associated with the prediction of recurrence free survival and of treatment-refractory disease. Markers developed un urine samples are focused on commercially available kits, which currently do not unequivocally show strongly superior levels of accuracy to cytology. However, they have demonstrated to be potentially helpful in the prediction of recurrence. Blood-based biomarkers represent an emerging reality with promising future applications.

CONCLUSIONS

Despite a long history of attempts to discover accurate biomarkers predicting oncological outcomes for HR NMIBC, contradictory or uncertain findings render the adoption of this ancillary techniques in clinical practice still unlikely. Future attempts should be directed to the development of prospective trials and the definition of standardized cut-off levels to render findings worthy of comparison.

Current progress in the clinical use of circulating tumor cells as prognostic biomarkers

The process of metastasis is characterized by the shedding of tumor cells into the bloodstream, where they are transported to other parts of the body to seed new tumors. These cells, known as circulating tumor cells (CTCs), have the potential to reveal much about an individual cancer case, and theoretically can aid in the prediction of outcomes and design of precision treatments. Recent advances in technology now allow for the robust and reproducible characterization of CTCs from a simple blood draw. Both the number of circulating cells and important molecular characteristics correlated with clinical phenotypes such as drug resistance can be obtained and used for real-time prognostic analysis. Molecular characterization can provide a snapshot of the activity of the main tumor (serving as a "liquid biopsy") and early warnings concerning changes such as the development of resistance, and aid in predicting the efficacy of different therapeutic approaches for treatment optimization. Herein, the authors review the current clinical use of CTCs as prognostic biomarkers for several different cancers. The quantification of CTCs can lead to more accurate staging and decision making regarding options such as adjuvant chemotherapy.