PD-L1 expression in bladder primary in situ urothelial carcinoma: evaluation in BCG-unresponsive patients and BCG responders

BCG and bladder cancer. Forty-eight years after Morales report

Although BCG use as an anticancer drug was nearly abandoned due to the poor results in most tumors, in 1976 Morales reported a relevant reduction in recurrence with intravesical BCG in few patients affected by NMIBC. Since then BCG was globally accepted as an empirical and effective therapy in treating Tis and preventing recurrence of intermediate and high risk NMIBC. Forty-eight years after Morales' report, although some open questions remain object of debate, we have been able to find answers to many doubts improving BCG activity and toxicity. We better select patients undergoing BCG and many trials have indicated the best dosage and schedule. Moreover, we are able to better identify the patient unresponsive to BCG who might benefit of a timely radical cystectomy. We are also aware of the difficulties and toxicities that can be encountered with BCG use in every-day clinical practice. Research is ongoing to obtain genetically modified BCG to increase its efficacy and reduce toxicity. Moreover, the combination of BCG with other immunotherapeutic drugs given intravesically or systemically, first immune checkpoint inhibitors, is under study to obtain a response in patients unresponsive or intolerant to BCG. Almost 50 years after Morales publication, intravesical BCG remains an inalienable tool against NMIBC.

Breaking Barriers: Modulation of Tumor Microenvironment to Enhance Bacillus Calmette-Guérin Immunotherapy of Bladder Cancer

The clinical management of bladder cancer continues to present significant challenges. Bacillus Calmette-Guérin (BCG) immunotherapy remains the gold standard of treatment for non-muscle invasive bladder cancer (NMIBC), but many patients develop recurrence and progression to muscle-invasive disease (MIBC), which is resistant to BCG. This review focuses on the immune mechanisms mobilized by BCG in bladder cancer tumor microenvironments (TME), mechanisms of BCG resistance, the dual role of the BCG-triggered NFkB/TNFα/PGE2 axis in the regulation of anti-tumor and tumor-promoting aspects of inflammation, and emerging strategies to modulate their balance. A better understanding of BCG resistance will help develop new treatments and predictive biomarkers, paving the way for improved clinical outcomes in bladder cancer patients.

Integrating the PD-L1 Prognostic Biomarker in Non-Muscle Invasive Bladder Cancer in Clinical Practice-A Comprehensive Review on State-of-the-Art Advances and Critical Issues

Bladder cancer (BC) is one of the most prevalent cancers worldwide. Non-muscle invasive bladder cancer (NMIBC), comprising the majority of initial BC presentations, requires accurate risk stratification for optimal management. This review explores the evolving role of programmed cell death ligand 1 (PD-L1) as a prognostic biomarker in NMIBC, with a particular focus on its implications in the context of Bacillus Calmette-Guérin (BCG) immunotherapy. The literature suggests a potential association between elevated PD-L1 status and adverse outcomes, resistance to BCG treatment, and disease progression. However, conflicting findings and methodological issues highlight the heterogeneity of PD-L1 assessment in NMIBC, probably due to the complex biological mechanisms that regulate the interaction between PD-L1 and the tumor microenvironment. The identification of PD-L1 as a prognostic biomarker provides ground for tailored therapeutic interventions, including immune checkpoint inhibitors (ICIs). Nevertheless, challenges such as intratumoral heterogeneity and technical issues underscore the need for standardized protocols and larger, homogeneous trials. This review contributes to the ongoing debate on the personalized management of NMIBC patients, focusing on the advances and perspectives of incorporating PD-L1 as a biomarker in this setting.

Methylation Analysis of Urinary Sample in Non-Muscle-Invasive Bladder Carcinoma: Frequency and Management of Invalid Result

BACKGROUND

Numerous studies showed that methylation analysis represents a newly developed urinary marker based on DNA methylation changes in a panel of genomic biomarkers and it could represent a valid tool in terms of the diagnosis and prediction of high-grade urothelial carcinoma recurrences. One of the limits of the use of this new molecular method during a follow-up is represented by the number of invalid tests in routine practice.

METHOD

A total of 782 patients with a diagnosis of non-muscle-invasive high-grade carcinoma (NMIBC) was studied. The Bladder EpiCheck test (BE) was performed together with cytology in all cases within 1 year after the end of treatment. In 402 patients, the urinary samples were voided urine (UV), while, in 380 cases, the samples were collected after bladder washing (IU). For all the patients with invalid BE results, a second BE test was performed following the instructions for use that indicated the test should be repeated with a new urinary sample in the case of an invalid result.

RESULTS

Analyzing the two different groups (UV and IU), we found the invalid BE results seemed to be not related to urinary samples (p = 0.13 Fisher's exact test), suggesting that the collection method was not relevant in order to reduce the number of invalid tests.

CONCLUSIONS

In the follow-up for NMIBC, for patients for whom a BE test is planned, a combined approach of cytology and a methylation test is recommended in order to repeat the BE test with an invalid result only in those cases with a cytological diagnosis of atypical urothelial cells (AUC) suspicious for high-grade urothelial carcinoma (SHGUC) and high-grade urothelial carcinoma (HGUC).

The Role of Checkpoint Inhibitor Expression Directly on Exfoliated Cells from Bladder Cancer: A Narrative Review

Bladder cancer (BCa) is a common type of cancer that affects the urinary bladder. The early detection and management of BCa is critical for successful treatment and patient outcomes. In recent years, researchers have been exploring the use of biomarkers as a non-invasive and effective tool for the detection and monitoring of BCa. One such biomarker is programmed death-ligand 1 (PD-L1), which is expressed on the surface of cancer cells and plays a crucial role in the evasion of the immune system. Studies have shown that the PD-L1 expression is higher in BCa tumors than in healthy bladder tissue. Additionally, PD-L1 expression might even be detected in urine samples in BCa patients, in addition to the examination of a histological sample. The technique is being standardized and optimized. We reported how BCa patients had higher urinary PD-L1 levels than controls by considering BCa tumors expressing PD-L1 in the tissue specimen. The expression of PD-L1 in urinary BCa cells might represent both a diagnostic and a prognostic tool, with the perspective that the PD-L1 expression of exfoliate urinary cells might reveal and anticipate eventual BCa recurrence or progression. Further prospective and longitudinal studies are needed to assess the expression of PD-L1 as a biomarker for the monitoring of BCa patients. The use of PD-L1 as a biomarker for the detection and monitoring of BCa has the potential to significantly improve patient outcomes by allowing for earlier detection and more effective management of the disease.

Role of PD-1/PD-L1-mediated tumour immune escape mechanism and microsatellite instability in the BCG failure of high-grade urothelial carcinomas

BACKGROUND

Intravesical BCG treatment fails inexplicably in 30%-45% of patients for high-grade nonmuscle-invasive bladder cancer (NMIBC). We aimed to investigate the role of PD-1/PD-L1 interaction on BCG failure of high-grade NMIBC and to identify biomarkers for predicting BCG responsive cases.

METHODS

Thirty BCG responsive and 29 nonresponsive NMIBCs were included in the study. Expressions of PDL1(SP-263), MSH2, MSH6, PMS2, and MLH1 were evaluated on pre- and post-BCG transurethral resection (TUR-B) specimens by immunohistochemistry. PD-L1(SP-263) expression was categorised as negative/low, high. DNA mismatch repair protein (MMR) expressions were classified as "reduced" if ≤30% of nuclei stained, "preserved" if >30% of nuclei stained. Microsatellite instability (MSI) testing was performed by PCR using five mononucleotide markers.

RESULTS

Reduced DNA MMR protein expression was found to be significantly higher in the pretreatment biopsies of BCG-responsive group than the BCG nonresponsive tumour group (p = 0.022). PD-L1 expression did not show any significant difference between the pre- and posttreatment TUR-B specimens of the BCG nonresponsive tumour group or between the pretreatment TUR-B specimens of BCG nonresponsive and the BCG responsive groups (p = 0.508, p = 0.708, respectively).

DISCUSSION

Immune escape of tumour cells by PD-1/PD-L1 interaction does not seem to have any role in BCG failure of NMIBCs. Reduced MMR expression may help to determine cases that will respond well to BCG therapy. A better antitumour activity of BCG in NMIBCs with reduced MMR expression may be related to the ongoing accumulation of cancer neoantigens in correlation with increased tumour mutation load as a result of DNA repair defects.

Role of Intravesical BCG as a Therapeutic Vaccine for Treatment of Bladder Carcinoma

Bacterial products have attracted much attention as potential antitumor agents, with the ability to provide direct tumoricidal effects, leading to the inhibition of tumor growth. Treatment of superficial bladder cancer with intravesical Bacillus Calmette-Guérin (BCG) has a more reduction potential than surgery in tumor recurrence rate. BCG, the gold standard for nonmuscle invasive bladder cancer, is manufactured from different strains and produced commercially with varied strengths. There are a few countries known as the manufacturer of this strategic biopharmaceutical product, and Iran as a member of the Eastern Mediterranean Region plays a vital role in supplying this vaccine. Studies have failed to uncover the exact mechanism of action of the intravesical; however, evidence points toward an immunogenic mechanism that proficiently modifies a biologic response and provokes the immune cells in order to kill and suppress tumors. Among various underlying mechanisms, BCG bacillus attachment to fibronectin through its fibronectin attachment protein is a pivotal mechanism for BCG tumoricidal activity.

Non-muscle invasive bladder cancer biomarkers beyond morphology

Non-muscle invasive bladder cancer (NMIBC) still represents a challenge in decision-making and clinical management since prognostic and predictive biomarkers of response to treatment are still under investigation. In addition to the risk factors defined by EORTC guidelines, histological features have also been considered key variables able to impact on recurrence and progression in bladder cancer. Conversely, the role of genomic rearrangements or expression of specific proteins at tissue level need further assessment in NMIBC. As with muscle-invasive cancer, NMIBC is a heterogeneous disease, characterized by genomic instability, varying rates of mutation and a wide range of protein tissue expression. In this Review, we summarized the recent evidence on prognostic and predictive tissue biomarkers in NMIBC, beyond morphological parameters, outlining how they could affect tumor biology and consequently its behavior during clinical care. Our aim was to facilitate clinical evaluation of promising biomarkers that may be employed to better stratify patients. We described the most common molecular events and immunohistochemical protein expressions linked to recurrence and progression. Moreover, we discussed the link between available treatments and molecular drivers that could be predictive of clinical response. In conclusion, we foster further investigations with particular focus on immunohistochemical evaluation of tissue biomarkers, a promising and cost-effective tool for daily practice.

Predictive biomarkers of response to bacillus Calmette‐Guérin immunotherapy and bacillus Calmette‐Guérin failure for non‐muscle invasive bladder cancer

Within the heterogeneous population of patients with bacillus Calmette‐Guérin failure, there are clear differences in prognosis and therapy with regard to the timeline when bacillus Calmette‐Guérin failure occurred. There are a variety of classifications which include bacillus Calmette‐Guérin refractory disease, relapsing, unresponsive, and intolerant. Further profiling of these patients may help to shed light on other forms of therapy that are less radical. We hereby summarize the different biomarkers that predicts for response to bacillus Calmette‐Guérin immunotherapy and bacillus Calmette‐Guérin failure for non‐muscle invasive bladder cancer.

New Perspectives in the Medical Treatment of Non-Muscle-Invasive Bladder Cancer: Immune Checkpoint Inhibitors and Beyond

Non-muscle-invasive bladder cancer (NMIBC) is characterized by a high rate of cure, but also by a non-negligible probability of recurrence and risk progression to muscle-invasive disease. NMIBC management requires a proper local resection and staging, followed by a risk-based treatment with intravesical agents. For many years, the current gold standard treatment for patients with intermediate or high-risk disease is transurethral resection of the bladder (TURB) followed by intravesical bacillus Calmette–Guérin (BCG) instillations. Unfortunately, in about half of high-risk patients, intravesical BCG treatment fails and NMIBC persists or recurs early. While radical cystectomy remains the gold standard for these patients, new therapeutic targets are being individuated and studied. Radical cystectomy in fact can provide an excellent long-term disease control, but can deeply interfere with quality of life. In particular, the enhanced immune checkpoints expression shown in BCG-unresponsive patients and the activity of immune checkpoints inhibitors (ICIs) in advanced bladder cancer provided the rationale for testing ICIs in NMIBC. Recently, pembrolizumab has shown promising activity in BCG-unresponsive NMIBC patients, obtaining FDA approval. Meanwhile multiple novel drugs with alternative mechanisms of action have proven to be safe and effective in NMIBC treatment and others are under investigation. The aim of this review is to analyse and describe the clinical activity of new emerging drugs in BCG-unresponsive NMIBC focusing on immunotherapy results.

Predictors of response to BCG therapy in non-muscle invasive bladder cancer

Intravesical BCG (Bacillus Calmette-Guerin) therapy represents the therapy of choice for intermediary and high risk NMIBC after transurethral resection. However, up to 40% of these patients do not show adequate response to the therapy (BCG failure) and 15% of them experience the progression of the disease to muscle-invasive bladder cancer. In such cases, radical cystectomy is indicated. Studies suggest that early radical cystectomy in patients with BCG failure is followed by better survival compared to delayed radical cystectomy. The prediction of response to BCG therapy could enable early identification of patients on which this therapy would have no effect and who should undergo early radical cystectomy.

Improving Anti-PD-1/PD-L1 Therapy for Localized Bladder Cancer

In high-risk non-muscle invasive bladder cancer (HR-NMIBC), patient outcome is negatively affected by lack of response to Bacillus-Calmette Guérin (BCG) treatment. Lack of response to cisplatin-based neoadjuvant chemotherapy and cisplatin ineligibility reduces successful treatment outcomes in muscle-invasive bladder cancer (MIBC) patients. The effectiveness of PD-1/PD-L1 immune checkpoint inhibitors (ICI) in metastatic disease has stimulated its evaluation as a treatment option in HR-NMIBC and MIBC patients. However, the observed responses, immune-related adverse events and high costs associated with ICI have provided impetus for the development of methods to improve patient stratification, enhance anti-tumorigenic effects and reduce toxicity. Here, we review the challenges and opportunities offered by PD-1/PD-L1 inhibition in HR-NMIBC and MIBC. We highlight the gaps in the field that need to be addressed to improve patient outcome including biomarkers for response stratification and potentially synergistic combination therapy regimens with PD-1/PD-L1 blockade.

Narrative review: update on immunotherapy and pathological features in patients with bladder cancer

Over the last few years efficacy of immunotherapy using immune checkpoint inhibitors (ICI) has been investigated in patients with bladder cancer (BC) at all stages. The present article aims to assess new therapeutic options with emerging agents in BC patients, shedding light on ICI-based treatments encompassing all disease stages, from non-muscle invasive (NMIBC) to muscle-invasive (MIBC) BC, concluding with metastatic MIBC. In bacillus Calmette-Guerin (BCG) unresponsive patients with carcinoma in situ, pembrolizumab has been recently approved. In the neoadjuvant setting, results from two clinical trials seem to identify pathological and genomic features of highly responsive tumors. Squamous cells and lymphoepithelioma/like histotypes, programmed cell-death ligand 1 (PD-L1) expression and high levels of activate T cells have been associated with higher response rate. In the metastatic setting, only 30% of patient may respond to ICI. A panel of biomarkers for patient selection is an actual need since the correlation between response and PD-L1 expression seem inconsistent across clinical trials, with some exceptions. Molecular characterization of BC, tumor mutation burden and immune-gene expression profiling might introduce new molecular biomarkers, hopefully transferable into the clinical-pathological practice.

The prognostic value of programmed cell death protein ligand 1 in patients with non-muscle-invasive bladder cancer treated with bacille Calmette-Guérin immunotherapy: Current status

Objective

To summarise the current evidence of the significance and prognostic value of programmed cell death protein ligand 1 (PD-L1) expression in patients with non-muscle-invasive bladder cancer (NMIBC) treated with bacille Calmette–Guérin (BCG) immunotherapy.

Methods

A search was conducted in May 2020 of three electronic databases; MEDLINE, Scopus, and EMBASE. In this review we included results from original studies investigating the relationship between the PD-L1 expression and BCG response in patients with NMIBC.

Results

Only five relevant articles were identified in the literature to date. Some studies showed an association between increased PD-L1 expression and BCG unresponsiveness; however, other authors provided contradictory results and suggested that PD-L1 evaluation could not be used for reliable prediction of BCG response.

Conclusions

The value of PD-L1 evaluation in predicting BCG response is debatable. Current evidence, based only on retrospective analyses, is inconsistent. Comparability of the results is diminished by the methodological limitations of immunohistochemistry assessment. Further multicentre, randomised trials are needed to make definitive conclusions.

Abbreviations

ICs: immune cells; IHC: immunohistochemical staining; (N)MIBC: (non-) muscle-invasive bladder cancer; PD-L1: programmed cell death protein ligand 1; PD-1: programmed cell death protein 1; RC: radical cystectomy; TCs: tumour cells.

Methylation study of the Paris system for reporting urinary (TPS) categories

AIMS

Bladder EpiCheck is one of several urinary tests studied to identify bladder tumours and analyses 15 methylation biomarkers determining bladder cancer presence on the basis of methylation profile.

METHODS

374 patients diagnosed with high-grade non-muscle invasive bladder cancer were treated and followed for 1 year with voided urine cytology and white-light cystoscopy and biopsies according to European Association of Urology Guidelines. 268 cases were diagnosed with high-grade papillary carcinoma, while 106 cases were carcinoma in situ. Bladder EpiCheck test was performed together with cytology in all cases.

RESULTS

Comparing cytological categories of negative for high-grade urothelial carcinoma (NHGUC) and atypical urothelial cells (AUCs), we found that an EpiScore <60 correlates with NHGUC (p=0.0003, Fisher's exact test), while comparing AUC and suspicious for high-grade urothelial carcinoma (SHGUC) or SHGUC and high-grade urothelial carcinoma (HGUC) categories, an EpiScore ≥60 correlates with SHGUC and HGUC, respectively (p=0.0031 and p=0.0027, Fisher's exact test). In each TPS category, we found that sensitivity, specificity, Positive Predicitve Value (PPV) and Negative Predictive Value (NPV) of the Bladder EpiCheck test in HGUC category were higher than those observed in SHGUC group (sensitivity=98%, specificity=100%, NPV=85.7%, PPV=100% vs sensitivity=86.6%, specificity=52.3%, NPV=84.6%, PPV=56.5%).

CONCLUSIONS

Analysing methylation study results, we demonstrated that different TPS cytological categories also carry a distinct molecular signature. Moreover, our results confirm that cytological categories SHGUC and HGUC are different entities also from a molecular point of view and should continue to represent distinct groups in TPS.