Current status of genetic urinary biomarkers for surveillance of non-muscle invasive bladder cancer: a systematic review

Epigenetic alterations in urothelial bladder cancer associated with disease outcomes

OBJECTIVES

Bladder cancer (BLCA) is a molecular heterogeneous disease with known genetic distinctive signatures. However, DNA methylation is highly prevalent across a wide range of tumors, suggesting its potential in oncogenesis. Here, we aimed to interrogate the role of nine epigenetic alterations as diagnostic and prognostic markers in BLCA.

METHODS

DNA methylation, gene expression, and clinicopathological information were retrieved from The Cancer Genome Atlas data portal. Methylation values and gene expression were assessed to determine their association with normal and malignant tissue. Additionally, we studied the association between methylation values and clinicopathological variables. For the prognostic model, Kaplan-Meier Survival curves were generated. Lastly, univariate and multivariate analysis were performed to evaluate the simultaneous impact of methylation and clinicopathological variables on the risk of tumor progression and survival.

RESULTS

Nine CpG sites' methylation β -values involved in our study demonstrated different methylation signatures between normal and malignant urothelium. Hypermethylated CpGs were overrepresented in tumor tissue (p < 0.0001). Opposingly, 4 CpG sites showed lower methylation values in tumor samples (p < 0.0001). Cg12743248high and cg17192862low are risk factors for progression-free survival, whereas cg12374721high (HR:3.003 (1.283-7.030)) also demonstrated to be the most valuable independent risk factor for disease progression and a risk factor for overall survival.

CONCLUSIONS

We have identified that methylated cg12374721 shows promise as a diagnostic and independent prognostic marker in BLCA progression.

Use of Multiple Machine Learning Approaches for Selecting Urothelial Cancer-Specific DNA Methylation Biomarkers in Urine

Diagnosing urothelial cancer (UCa) via invasive cystoscopy is painful, specifically in men, and can cause infection and bleeding. Because the UCa risk is higher for male patients, urinary non-invasive UCa biomarkers are highly desired to stratify men for invasive cystoscopy. We previously identified multiple DNA methylation sites in urine samples that detect UCa with a high sensitivity and specificity in men. Here, we identified the most relevant markers by employing multiple statistical approaches and machine learning (random forest, boosted trees, LASSO) using a dataset of 251 male UCa patients and 111 controls. Three CpG sites located in ALOX5, TRPS1 and an intergenic region on chromosome 16 have been concordantly selected by all approaches, and their combination in a single decision matrix for clinical use was tested based on their respective thresholds of the individual CpGs. The combination of ALOX5 and TRPS1 yielded the best overall sensitivity (61%) at a pre-set specificity of 95%. This combination exceeded both the diagnostic performance of the most sensitive bioinformatic approach and that of the best single CpG. In summary, we showed that overlap analysis of multiple statistical approaches identifies the most reliable biomarkers for UCa in a male collective. The results may assist in stratifying men for cystoscopy.

Higher Expression of Annexin A2 in Metastatic Bladder Urothelial Carcinoma Promotes Migration and Invasion

In this study, we aim to evaluate the significance of AnxA2 in BLCA and establish its metastatic role in bladder cancer cells. Analysis of TCGA data showed that AnxA2 mRNA expression was significantly higher in BLCA tumors than in normal bladder tissues. High mRNA expression of AnxA2 in BLCA was significantly associated with high pathological grades and stages, non-papillary tumor histology, and poor overall survival (OS), progression-free survival (PFS), and diseases specific survival (DSS). Similarly, we found that AnxA2 expression was higher in bladder cancer cells derived from high-grade metastatic carcinoma than in cells derived from low-grade urothelial carcinoma. AnxA2 expression significantly mobilized to the surface of highly metastatic bladder cancer cells compared to cells derived from low-grade tumors and associated with high plasmin generation and AnxA2 secretion. In addition, the downregulation of AnxA2 cells significantly inhibited the proliferation, migration, and invasion in bladder cancer along with the reduction in proangiogenic factors and cytokines such as PDGF-BB, ANGPT1, ANGPT2, Tie-2, bFGF, GRO, IL-6, IL-8, and MMP-9. These findings suggest that AnxA2 could be a promising biomarker and therapeutic target for high-grade BLCA.

Tumoral markers in bladder cancer (Review)

Bladder tumors are frequently diagnosed urologic malignant diseases with an extremely high recurrence rate compared to other neoplastic tumors. Urothelial bladder carcinomas are mostly identified in their incipient form, as non-muscle invasive, but despite that, a third of them develop into aggressive recurrent disease. The diagnosis of bladder carcinoma at this moment is established using cytology and cystoscopy and is a great challenge for clinicians due to the lack of sensitivity. Urinary biomarkers could improve and enhance the diagnosis and screening techniques and determine a more accurate recurrence rate. However, bladder cancer is a heterogeneous disease and the existence of a single marker test with reduced cost is unlikely; thus, until then, the use of a panel of markers to obtain valuable information is inevitable even though suboptimal for use. To improve this deadlock, new biomarker panels should be identified and prepared to equalize the cost-efficiency balance. The present paper is a literature review concerning the most commonly used tumor markers in urinary bladder cancer as well as the most commonly encountered genetic modifications in such patients.

Hexylaminolevulinate-mediated fluorescent urine cytology with a novel automated detection technology for screening and surveillance of bladder cancer

OBJECTIVES

To evaluate the diagnostic performance of fluorescent voided urine cytology (FVUC) using a novel automated detection technology to screen for primary bladder cancer and for surveillance of recurrent bladder tumour.

PATIENTS AND METHODS

We created a rapid, objective, automated, and high-throughput detection device for hexylaminolevulinate-mediated FVUC, named the cellular fluorescence analysis unit-II (CFAU-II). Two different cohorts were used in this study: (i) screening test for primary bladder cancer (165 patients with bladder cancer and 52 controls), and (ii) surveillance test for detecting intravesical recurrent tumour (192 patients with treated non-muscle-invasive bladder cancer and 15 with post-nephroureterectomy upper urinary tract cancer). Voided urine samples were subjected to urine analysis, conventional VUC (cVUC), and FVUC. Diagnostic performance was compared between cVUC, FVUC, and a combination of the two.

RESULTS

A total of 614 urine samples were successfully collected, processed, and analysed. Comparative analysis of the screening test cohort demonstrated that the overall sensitivity of FVUC (63%, P < 0.001) and combination testing (72%, P < 0.001) was significantly higher than that of cVUC (29%). FVUC was found to be superior in most of the subgroups, especially in low-grade, Ta, and small tumours. Analysis of the surveillance test cohort showed that combination testing achieved a sensitivity of 82% and a negative predictive value of 98%, whereas those of cVUC were 39% and 96%, respectively. According to the pathological finding of recurrent tumours presenting false-negative result in the FVUC, the majority of the overlooked recurrent diseases were Ta low-grade tumours. Logistic regression analysis suggested an association between the risk of false-positive results and high density of urine white blood cells and alkaluria.

CONCLUSION

The present findings clearly demonstrate that FVUC using the newly developed automation technology has superior sensitivity to cVUC for both screening for primary bladder cancer and recurrent tumour detection. It is essential to confirm the clinical usefulness of this method via further large-scale studies, in addition to ensuring its affordability and availability.

Refining assessment of response to radiation-based therapy for muscle-invasive bladder cancer: Is post-treatment tumor bed biopsy always necessary?

INTRODUCTION

Radiation-based therapy (RT) has emerged as a suitable alternative to radical cystectomy (RC) and pelvic lymph node dissection for muscle-invasive bladder cancer (MIBC) patients. Routine biopsy after RT to rule out residual disease remains inconsistent across guidelines. Our objective was to review the significance of a bladder biopsy in terms of assessment of response post-RT and its potential impact on survival.

PATIENTS AND METHODS

This was a single-center retrospective study on patients with MIBC (cT2-4aN0-2M0) treated with curative intent RT. A total of 169 patients with primary urothelial carcinoma were analyzed. Patients' demographic, clinical and pathological variables, imaging, cystoscopy, urine cytology, and biopsy reports after RT were collected and compiled. Whenever urine cytology was positive or cystoscopy showed any malignant-appearing lesion, the first assessment post-RT was considered suspicious for residual disease. A descriptive population analysis was reported. Cox regression multivariable analysis was performed to identify independent variables associated with survival outcomes.

RESULTS

Median age was 75 years (interquartile range 66-82) and clinical staging was cT2 in 152 (90%) patients. Cytology and cystoscopy were normal in 140 (83%) after RT. Of patients with a control biopsy, residual MIBC was present in 3 (5%) and non-MIBC in another 6 (11%). On the contrary, a for-cause biopsy due to a suspicious assessment post-RT did not yield residual cancer in 45% of patients. Multivariable analysis showed that age (hazard ratio [HR] 1.04, P< 0.001), lymphovascular invasion (HR 1.68, P = 0.03) and a suspicious assessment after RT (HR 3.21; P< 0.001) were significantly associated with worse OS. This study was limited by its retrospective design.

CONCLUSIONS

A routine biopsy after RT may be warranted to assess treatment response. This might be particularly important for patients who may benefit from early surgical intervention for residual MIBC. Further prospective studies are needed to confirm our findings.