Detection of specific chromosomal aberrations in urine using BCA-1 (oligo-CGH-array) enhances diagnostic sensitivity and predicts the aggressiveness of non-muscle-invasive bladder transitional cell carcinoma

Urine biomarkers in bladder cancer - current status and future perspectives

Urine markers to detect bladder cancer have been the subject of research for decades. The idea that urine - being in continuous contact with tumour tissue - should provide a vector of tumour information remains an attractive concept. Research on this topic has resulted in a complex landscape of many different urine markers with varying degrees of clinical validation. These markers range from cell-based assays to proteins, transcriptomic markers and genomic signatures, with a clear trend towards multiplex assays. Unfortunately, the number of different urine markers and the efforts in research and development of clinical grade assays are not reflected in the use of these markers in clinical practice, which is currently limited. Numerous prospective trials are in progress with the aim of increasing the quality of evidence about urinary biomarkers in bladder cancer to achieve guideline implementation. The current research landscape suggests a division of testing approaches. Some efforts are directed towards addressing the limitations of current assays to improve the performance of urine markers for a straightforward detection of bladder cancer. Additionally, comprehensive genetic analyses are emerging based on advances in next-generation sequencing and are expected to substantially affect the potential application of urine markers in bladder cancer.

Trends in urine biomarker discovery for urothelial bladder cancer: DNA, RNA, or protein?

Urothelial bladder cancer is a complex disease displaying a landscape of heterogenous molecular subtypes, mutation profiles and clinical presentations. Diagnosis and surveillance rely on flexible cystoscopy which has high accuracy, albeit accompanied by a high-cost burden for healthcare providers and discomfort for patients. Advances in "omic" technologies and computational biology have provided insights into the molecular pathogenesis of bladder cancer and provided powerful tools to identify markers for disease detection, risk stratification, and predicting responses to therapy. To date, numerous attempts have been made to discover and validate diagnostic biomarkers that could be deployed as an adjunct to the cystoscopic diagnosis and long-term surveillance of bladder cancer. We report a comprehensive literature analysis using PubMed to assess the changing trends in investigating DNA, RNA, or proteins as diagnostic urinary biomarkers over a period of 5 decades: 1970-2020. A gradual shift has been observed in research away from protein biomarkers to nucleic acids including different classes of RNA, and DNA methylation and mutation markers. Until 2000, publications involving protein biomarker discovery constituted 87% of the total number of research articles with DNA comprising 6% and RNA 7%. Since 2000 the proportion of protein biomarker articles has fallen to 40%, and DNA and RNA studies increased to 32% and 28%, respectively. Clearly research focus, perhaps driven by technological innovation, has shifted from proteins to nucleic acids. We optimistically hypothesise that, following thorough validation, a clinically useful detection test for bladder cancer based on a panel of DNA or RNA markers could become reality within 5-10 years.

Health Related Quality of life in bladder cancer. Current approach and future perspectives

Bladder cancer is a real health problem due to its increased incidence, high recurrence rate and the fact that usually it is detected in advanced stages with limited number of diagnostic tools and different therapy response rates to current therapeutic strategies. Because of these issues we must develop screening programs and sensitive diagnostic strategies capable of detecting the disease during its early stages but also for characterizing evolution, prognosis and therapeutic response. Issues of great importance are those related to health quality of life of patients from the moment of diagnosis till the use of existing therapeutic approaches. This paper reviews some facets of life quality in patients diagnosed with bladder cancer stressing upon some proposed questionnaires and some new cell and molecular biology and genomic acquisitions (molecular biomarkers) that may become indicators of prognosis, therapeutic response and life quality but also essential tools in guiding therapeutic strategies.

[Correlation of genetic and cytogenetic alterations in pathological aggressiveness urothelial carcinoma of the bladder: Performance of BCA-1, a mini-array comparative genomic hybridisation-based test]

INTRODUCTION

Urothelial carcinomas are the fourth leading cause of cancer in humans. Their incidence is increasing by more than 50% in 25 years. The superficial forms (70% cases) require a close active surveillance to identify frequent recurrences and progression to invasive stage. Our main goal was to identify prognostic molecular markers for bladder cancer that could be used alone or in combination in routine clinical practice. In this aim, we evaluated the capability of the BCA-oligo test based on a CGH array to correctly classify tumoral grade/stage.

METHOD

Urinary DNA was extracted from 81 patients with superficial bladder cancer and has been hybridized on the BCA-oligo array. The results from the molecular analysis were correlated with the tumoral grade and stage.

RESULTS

Several chromosomal alterations were significantly more frequent in tumors of higher grade and more advanced stage. A significant association was observed between a high grade and the presence of one of these alterations: loss on 6p, gain on 8q or 13q, loss or gain on 9q or 11q, with an odds ratio of 6.91 (95% CI=2.20-21.64; P=0.0009). Moreover, a significant association was found between a more advanced stage (pT1) and the presence of one of these alterations: loss on 6p, gain on 8q, loss or gain on 5p, with an odds ratio of 15.2 (95% CI=3.71-62.58; P=0.0002).

CONCLUSION

Our results showed that molecular analyses of superficial bladder cancers based on urinary DNA and the BCA-oligo test could be used as prognostic factor for the tumor evolution, allowing then a more adapted clinical management.

Genomic complexity of urothelial bladder cancer revealed in urinary cfDNA

Urothelial bladder cancers (UBCs) have heterogeneous clinical characteristics that are mirrored in their diverse genomic profiles. Genomic profiling of UBCs has the potential to benefit routine clinical practice by providing prognostic utility above and beyond conventional clinicopathological factors, and allowing for prediction and surveillance of treatment responses. Urinary DNAs representative of the tumour genome provide a promising resource as a liquid biopsy for non-invasive genomic profiling of UBCs. We compared the genomic profiles of urinary cellular DNA and cell-free DNA (cfDNA) from the urine with matched diagnostic formalin-fixed paraffin-embedded tumour DNAs for 23 well-characterised UBC patients. Our data show urinary DNAs to be highly representative of patient tumours, allowing for detection of recurrent clinically actionable genomic aberrations. Furthermore, a greater aberrant load (indicative of tumour genome) was observed in cfDNA over cellular DNA (P<0.001), resulting in a higher analytical sensitivity for detection of clinically actionable genomic aberrations (P<0.04) when using cfDNA. Thus, cfDNA extracted from the urine of UBC patients has a higher tumour genome burden and allows greater detection of key genomic biomarkers (90%) than cellular DNA from urine (61%) and provides a promising resource for robust whole-genome tumour profiling of UBC with potential to influence clinical decisions without invasive patient interventions.

Using Copy Number Alterations to Identify New Therapeutic Targets for Bladder Carcinoma

Bladder cancer represents the ninth most widespread malignancy throughout the world. It is characterized by the presence of two different clinical and prognostic subtypes: non-muscle-invasive bladder cancers (NMIBCs) and muscle-invasive bladder cancers (MIBCs). MIBCs have a poor outcome with a common progression to metastasis. Despite improvements in knowledge, treatment has not advanced significantly in recent years, with the absence of new therapeutic targets. Because of the limitations of current therapeutic options, the greater challenge will be to identify biomarkers for clinical application. For this reason, we compared our array comparative genomic hybridization (array-CGH) results with those reported in literature for invasive bladder tumors and, in particular, we focused on the evaluation of copy number alterations (CNAs) present in biopsies and retained in the corresponding cancer stem cell (CSC) subpopulations that should be the main target of therapy. According to our data, CCNE1, MYC, MDM2 and PPARG genes could be interesting therapeutic targets for bladder CSC subpopulations. Surprisingly, HER2 copy number gains are not retained in bladder CSCs, making the gene-targeted therapy less interesting than the others. These results provide precious advice for further study on bladder therapy; however, the clinical importance of these results should be explored.