Expression of TIP60 (tat-interactive protein) and MRE11 (meiotic recombination 11 homolog) predict treatment-specific outcome of localised invasive bladder cancer

Current and Emerging Strategies to Treat Urothelial Carcinoma

Urothelial cell carcinoma (UCC, bladder cancer, BC) remains a difficult-to-treat malignancy with a rising incidence worldwide. In the U.S., UCC is the sixth most incident neoplasm and ~90% of diagnoses are made in those >55 years of age; it is ~four times more commonly observed in men than women. The most important risk factor for developing BC is tobacco smoking, which accounts for ~50% of cases, followed by occupational exposure to aromatic amines and ionizing radiation. The standard of care for advanced UCC includes platinum-based chemotherapy and programmed cell death (PD-1) or programmed cell death ligand 1 (PD-L1) inhibitors, administered as frontline, second-line, or maintenance therapy. UCC remains generally incurable and is associated with intrinsic and acquired drug and immune resistance. UCC is lethal in the metastatic state and characterized by genomic instability, high PD-L1 expression, DNA damage-response mutations, and a high tumor mutational burden. Although immune checkpoint inhibitors (ICIs) achieve long-term durable responses in other cancers, their ability to achieve similar results with metastatic UCC (mUCC) is not as well-defined. Here, we discuss therapies to improve UCC management and how comprehensive tumor profiling can identify actionable biomarkers and eventually fulfill the promise of precision medicine for UCC patients.

Homologous recombination mRNAs (RAD21, RAD50 and BARD1) have a potentially poor prognostic role in ERBB2-low bladder cancer patients

Human epidermal growth factor receptor 2 (HER2/ERBB2) factor is known to be implicated in many malignancies and the potential of it as a prognostic biomarker was reported years ago. Molecular subtypes of HER2/ERBB2 negative and positive with distinct clinical outcomes have been identified in recent years; however, it is still under investigation for bladder cancer. This study evaluates the biological and prognostic significance of RAD21, RAD50 and BARD1 (homologous recombination biomarkers) mRNA levels with ERBB2 low and high expression to explore their impact on bladder cancer patient survival and cancer aggressiveness. The expression of ERBB2, RAD21, RAD50 and BARD1 mRNA levels was assessed in The Cancer Genome Atlas (TCGA) bladder cancer dataset along with four validation cohorts. Outcome analysis was evaluated using disease-free survival (DFS) and overall survival (OS). Univariate and multivariate analysis were used to evaluate the relationship between RAD21, RAD50, BARD1 and ERBB2 expression and clinicopathological variables. A significant increase in mRNA expression levels of RAD21, RAD50 and BARD1 was noticed in ERBB2-low patients compared to ERBB2-high patients. This overexpression of the homologous recombination repair transcripts was associated with poor outcome in ERBB2-low tumors, not in ERBB2-high tumors. Furthermore, the combined expression of high RAD21/RAD50, high RAD21/BARD1 or high RAD50/BARD1 were significantly associated with worse DFS and a better outcome for those with low co-expression in the ERBB2-low cohort. High expression of either RAD21/RAD50 or RAD21/BARD1 in ERBB2-low cohort associated with higher chance of metastasis. In addition, gene expression of BARD1 alone or in combination with RAD50 acted as an independent prognostic factor for worst survival. The data presented in this study reveal a connection between RAD21, RAD50, BARD1 and ERBB2 and patient survival. Importantly, it provided novel findings and potential prognostic markers, particularly in ERBB2-low bladder cancer.

The Multiple Faces of the MRN Complex: Roles in Medulloblastoma and Beyond

Hypomorphic mutations in MRN complex genes are frequently found in cancer, supporting their role as oncosuppressors. However, unlike canonical oncosuppressors, MRN proteins are often overexpressed in tumor tissues, where they actively work to counteract DSBs induced by both oncogene-dependent RS and radio-chemotherapy. Moreover, at the same time, MRN genes are also essential genes, since the constitutive KO of each component leads to embryonic lethality. Therefore, even though it is paradoxical, MRN genes may work as oncosuppressive, oncopromoting, and essential genes. In this review, we discussed how alterations in the MRN complex impact the physiopathology of cancer, in light of our recent discoveries on the gene-dosage-dependent effect of NBS1 in Medulloblastoma. These updates aim to understand whether MRN complex can be realistically used as a prognostic/predictive marker and/or as a therapeutic target for the treatment of cancer patients in the future.

Predicting tumour radiosensitivity to deliver precision radiotherapy

Owing to advances in radiotherapy, the physical properties of radiation can be optimized to enable individualized treatment; however, optimization is rarely based on biological properties and, therefore, treatments are generally planned with the assumption that all tumours respond similarly to radiation. Radiation affects multiple cellular pathways, including DNA damage, hypoxia, proliferation, stem cell phenotype and immune response. In this Review, we summarize the effect of these pathways on tumour responses to radiotherapy and the current state of research on genomic classifiers designed to exploit these variations to inform treatment decisions. We also discuss whether advances in genomics have generated evidence that could be practice changing and whether advances in genomics are now ready to be used to guide the delivery of radiotherapy alone or in combination.

Biomarkers in muscle invasive bladder cancer

Muscle invasive bladder cancer (MIBC) carries a poor prognosis with a 5-year overall survival rate of 40-50%. For localized disease, radical treatment options are cystectomy or radiotherapy with or without a radiosensitiser. Neoadjuvant or adjuvant chemotherapy is often delivered in addition to either. Metastatic disease can be treated with palliative systemic chemotherapy or immunotherapy. Standard clinicopathological information is insufficient to guide treatment decisions in several clinical scenarios in MIBC and there has been substantial effort to identify predictive and prognostic biomarkers. Despite this, no biomarker has been sufficiently qualified in prospective clinical trials to justify routine use. In this chapter we discuss these biomarkers and provide insight into the significant unmet need for robust biomarkers to inform treatment decisions and ultimately improve outcomes for bladder cancer patients.

Management of Localized Muscle-Invasive Bladder Cancer from a Multidisciplinary Perspective: Current Position of the Spanish Oncology Genitourinary (SOGUG) Working Group

This review presents challenges and recommendations on different aspects related to the management of patients with localized muscle-invasive bladder cancer (MIBC), which were discussed by a group of experts of a Spanish Oncology Genitourinary (SOGUG) Working Group within the framework of the Genitourinary Alliance project (12GU). It is necessary to clearly define which patients are candidates for radical cystectomy and which are candidates for undergoing bladder-sparing procedures. In older patients, it is necessary to include a geriatric assessment and evaluation of comorbidities. The pathological report should include a classification of the histopathological variant of MIBC, particularly the identification of subtypes with prognostic, molecular and therapeutic implications. Improvement of clinical staging, better definition of prognostic groups based on molecular subtypes, and identification of biomarkers potentially associated with maximum benefit from neoadjuvant chemotherapy are areas for further research. A current challenge in the management of MIBC is improving the selection of patients likely to be candidates for immunotherapy with checkpoint inhibitors in the neoadjuvant setting. Optimization of FDG-PET/CT reliability in staging of MIBC and the selection of patients is necessary, as well as the design of prospective studies aimed to compare the value of different imaging techniques in parallel.

MRE11 as a molecular signature and therapeutic target for cancer treatment with radiotherapy

MRE11, the core of the MRE11/RAD50/NBS1 complex, is one of key DNA damage response proteins. Increasing evidence suggests that its expression in cancer cells is critical to developing radioresistance; as such, MRE11 is an emerging marker for targeted radiosensitization strategies. Elevated MRE11 in tumor tissues has been associated with poor survival in patients undergoing radiotherapy, although in some cancer types, the opposite has been noted. The recent discovery of ionizing radiation-induced truncation of MRE11, which decreases its efficacy, may explain some of these paradoxical findings. The progress of research on the biological modulation of MRE11 expression is also discussed, with the potential application of small molecule or large molecule inhibitors of MRE11 for enhancing radiosensitivity. Current research has further highlighted both nuclease and non-nuclease activities of MRE11 in cancer cells treated with ionizing radiation, and differentiation between these is essential to verify the targeting effects of radiosensitizing agents. These updates clarify our understanding of how MRE11 expression may be utilized in future stratification of cancer patients for radiotherapy, and how it may be leveraged in shaping novel radiosensitization strategies.

Current State of Personalized Genitourinary Cancer Radiotherapy in the Era of Precision Medicine

Radiation therapy plays a crucial role for the management of genitourinary malignancies, with technological advancements that have led to improvements in outcomes and decrease in treatment toxicities. However, better risk-stratification and identification of patients for appropriate treatments is necessary. Recent advancements in imaging and novel genomic techniques can provide additional individualized tumor and patient information to further inform and guide treatment decisions for genitourinary cancer patients. In addition, the development and use of targeted molecular therapies based on tumor biology can result in individualized treatment recommendations. In this review, we discuss the advances in precision oncology techniques along with current applications for personalized genitourinary cancer management. We also highlight the opportunities and challenges when applying precision medicine principles to the field of radiation oncology. The identification, development and validation of biomarkers has the potential to personalize radiation therapy for genitourinary malignancies so that we may improve treatment outcomes, decrease radiation-specific toxicities, and lead to better long-term quality of life for GU cancer survivors.

Will the Use of Biomarkers Improve Bladder Cancer Radiotherapy Delivery?

Advances in the field of cancer biology and molecular techniques have led to a better understanding of the molecular underpinnings driving cancer development and outcomes. Simultaneously, advances in imaging have allowed for improved sensitivity in initial staging, radiotherapy planning and follow-up of numerous cancers. These two phenomena have led to the development of biomarkers that can guide therapy in multiple malignancies. In bladder cancer, there is extensive ongoing research into the identification of biomarkers that can help tailor personalised approaches for treatment based on the intrinsic tumour biology. However, the delivery of bladder cancer radiotherapy as part of trimodality therapy currently has a paucity of biomarkers to guide treatment. Here we summarise the existing literature and ongoing investigations into potential predictive and prognostic molecular and imaging biomarkers that may one day guide selection for utilisation of radiotherapy as part of trimodality therapy, guide selection of the radiosensitising agent, guide radiation dose and target, and guide surveillance for recurrence after trimodality therapy.

Contemporary and Emerging Approaches to Bladder-Preserving Trimodality Therapy for Muscle-Invasive Bladder Cancer

Bladder-preserving trimodality therapy (TMT), consisting of trans-urethral bladder tumor resection followed by concurrent chemoradiotherapy, is an established standard of care for patients with muscle-invasive bladder cancer. For appropriately selected patients, TMT offers oncologic outcomes comparable to radical cystectomy while preserving the patient's native bladder. Optimal TMT outcomes require careful patient selection, which is currently based on clinical and pathologic factors. The role of immune checkpoint blockade (ICB) in TMT is currently being investigated in several on-going clinical trials. In the future, molecular features associated with response to TMT or ICB may further improve patient selection and guide post-treatment surveillance.

SPRTN protease-cleaved MRE11 decreases DNA repair and radiosensitises cancer cells

The human MRE11/RAD50/NBS1 (MRN) complex plays a crucial role in sensing and repairing DNA DSB. MRE11 possesses dual 3'-5' exonuclease and endonuclease activity and forms the core of the multifunctional MRN complex. We previously identified a C-terminally truncated form of MRE11 (TR-MRE11) associated with post-translational MRE11 degradation. Here we identified SPRTN as the essential protease for the formation of TR-MRE11 and characterised the role of this MRE11 form in its DNA damage response (DDR). Using tandem mass spectrometry and site-directed mutagenesis, the SPRTN-dependent cleavage site for MRE11 was identified between 559 and 580 amino acids. Despite the intact interaction of TR-MRE11 with its constitutive core complex proteins RAD50 and NBS1, both nuclease activities of truncated MRE11 were dramatically reduced due to its deficient binding to DNA. Furthermore, lack of the MRE11 C-terminal decreased HR repair efficiency, very likely due to abolished recruitment of TR-MRE11 to the sites of DNA damage, which consequently led to increased cellular radiosensitivity. The presence of this DNA repair-defective TR-MRE11 could explain our previous finding that the high MRE11 protein expression by immunohistochemistry correlates with improved survival following radical radiotherapy in bladder cancer patients.

Review of Experimental Studies to Improve Radiotherapy Response in Bladder Cancer: Comments and Perspectives

Bladder cancer is among the top ten most common cancer types in the world. Around 25% of all cases are muscle-invasive bladder cancer, for which the gold standard treatment in the absence of metastasis is the cystectomy. In recent years, trimodality treatment associating maximal transurethral resection and radiotherapy combined with concurrent chemotherapy is increasingly used as an organ-preserving alternative. However, the use of this treatment is still limited by the lack of biomarkers predicting tumour response and by a lack of targeted radiosensitising drugs that can improve the therapeutic index, especially by limiting side effects such as bladder fibrosis. In order to improve the bladder-preserving treatment, experimental studies addressing these main issues ought to be considered (both in vitro and in vivo studies). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews, we conducted a literature search in PubMed on experimental studies investigating how to improve bladder cancer radiotherapy with different radiosensitising agents using a comprehensive search string. We made comments on experimental model selection, experimental design and results, formulating the gaps of knowledge still existing: such as the lack of reliable predictive biomarkers of tumour response to chemoradiation according to the molecular tumour subtype and lack of efficient radiosensitising agents specifically targeting bladder tumour cells. We provided guidance to improve forthcoming studies, such as taking into account molecular characteristics of the preclinical models and highlighted the value of using patient-derived xenografts as well as syngeneic models. Finally, this review could be a useful tool to set up new radiation-based combined treatments with an improved therapeutic index that is needed for bladder preservation.

Bladder-sparing protocols in the treatment of muscle-invasive bladder cancer

Bladder-sparing protocols (BSP) have been gaining widespread popularity as an attractive alternative to radical cystectomy (RC) for muscle-invasive bladder cancer. Unimodal therapies are inferior to multimodal regimens. The most promising regimen is trimodal therapy (TMT), which is a combination of maximal transurethral resection of bladder tumor (TURBT), radiotherapy, and chemotherapy. In appropriately selected patients (low volume unifocal T2 disease, complete TURBT, no hydronephrosis and no carcinoma-in-situ), comparable oncological outcomes to RC have been reported in large retrospective studies, with a potential improvement in overall quality of life (QOL). TMT also offers the possibility for definitive therapy for patients who are not surgically fit to undergo RC. Routine biopsy of previous tumor resection is recommended to assess response. Prompt salvage RC is required in non-responders and for recurrent muscle-invasive disease, while non-muscle-invasive recurrence can be managed conservatively with TURBT +/- intravesical BCG. Long-term follow-up consisting of routine cystoscopy, urine cytology, and cross-section imaging is required. Further studies are warranted to better define the role of neoadjuvant or adjuvant chemotherapy in the setting of TMT. Finally, future research on predictive markers of response to TMT and on the integration of immunotherapy in bladder sparing protocols is ongoing and is highly promising.

Bladder preservation: Translating discovery for clinical impact in urothelial cancer

Muscle-invasive bladder cancer can be treated with either radical cystectomy or bladder preservation approaches, and there is a need for reliable biomarkers to guide the optimal choice of therapy. The recent elucidation of the genomic landscape and biological drivers of bladder cancer has enabled the identification of tumor molecular features that may be helpful in driving clinical decision-making. Here, we summarize recent efforts to develop molecular biomarkers that could be leveraged to guide therapeutic decisions, post-treatment monitoring, and the optimal use of bladder preservation approaches for the effective treatment of muscle-invasive bladder cancer.

Setting the stage for bladder preservation

There is an underutilization of potentially curative treatments for patients with muscle-invasive bladder cancer. Contemporary trimodality bladder-preservation therapy - which includes a maximally safe transurethral resection of the bladder tumor followed by concurrent chemoradiation and close cystoscopic surveillance with salvage cystectomy reserved for invasive tumor recurrence - can help fulfill this unmet need. Over the past few decades, cumulative published data from prospective clinical trials and large institutional series have established trimodality therapy (TMT) for select patients as a safe and effective alternative to upfront cystectomy. Indeed, TMT is now supported as an accepted option for muscle-invasive bladder cancer patients by numerous clinical guidelines. Following TMT, the vast majority of long-term survivors maintain their native bladders, which tend to function well with relatively low rates of long-term toxicity and good long-term quality of life. There is the potential to further improve outcomes by optimizing systemic therapy integration and by validating predictive biomarkers for improved patient and treatment selection. TMT offers a unique opportunity for urologic surgeons, radiation oncologists and medical oncologists to work hand-in-hand in a multidisciplinary effort to deliver such therapy optimally, to support its research, to promote informed decision-making and ultimately to preserve the autonomy of patients with bladder cancer. The third annual meeting of the Johns Hopkins Greenberg Bladder Cancer Institute/American Urological Association Translational Research Collaboration allowed bladder cancer experts to meet and advance this mission.

Incidence and outcome of salvage cystectomy after bladder sparing therapy for muscle invasive bladder cancer: a systematic review and meta-analysis

Objective

We conducted a systematic review and meta-analysis to assess the available literature regarding the surgical and oncologic outcomes of patients undergoing salvage radical cystectomy (SV-RC) for recurrence or failure of bladder sparing therapy (BST) for muscle-invasive bladder cancer (MIBC).

Methods

We searched MEDLINE (PubMed), EMBASE and Google Scholar databases in May 2020. We included all studies of patients with ≥ cT2N0/xM0 bladder cancer that were eligible for all treatment modalities at the time of treatment decision who underwent BST including radiotherapy (RTX). A meta-analysis was conducted to calculate the pooled rate of several variables associated with an increased need for SV-RC. Study quality and risk of bias were assessed using MINORS criteria.

Results

73 studies comprising 9110 patients were eligible for the meta-analysis. Weighted mean follow-up time was 61.1 months (range 12–144). The pooled rate of non-response to BST and local recurrence after BST, the two primary reasons for SV-RC, was 15.5% and 28.7%, respectively. The pooled rate of SV-RC was 19.2% for studies with a follow-up longer than 5 years. Only three studies provided a thorough report of complication rates after SV-RC. The overall complication rate ranged between 67 and 72% with a 30-day mortality rate of 0–8.8%. The pooled rates of 5 and 10-year disease-free survival after SV-RC were 54.3% and 45.6%, respectively.

Conclusion

Approximately one-fifth of patients treated with BST with a curative intent eventually require SV-RC. This procedure carries a proportionally high rate of complications and is usually accompanied by an incontinent urinary diversion.

Electronic supplementary material

The online version of this article (10.1007/s00345-020-03436-0) contains supplementary material, which is available to authorized users.

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

BACKGROUND: Despite recent advances in the management of muscle-invasive bladder cancer (MIBC), treatment outcomes remain suboptimal, and variability exists across current practice patterns. OBJECTIVE: To promote standardization of care for MIBC in Canada by developing a consensus guidelines using a multidisciplinary, evidence-based, patient-centered approach who specialize in bladder cancer. METHODS: A comprehensive literature search of PubMed, Medline, and Embase was performed; and most recent guidelines from national and international organizations were reviewed. Recommendations were made based on best available evidence, and strength of recommendations were graded based on quality of the evidence. RESULTS: Overall, 17 recommendations were made covering a broad range of topics including pathology review, staging investigations, systemic therapy, local definitive therapy and surveillance. Of these, 10 (59% ) were level 1 or 2, 7 (41% ) were level 3 or 4 recommendations. There were 2 recommendations which did not reach full consensus, and were based on majority opinion. This guideline also provides guidance for the management of cisplatin-ineligible patients, variant histologies, and bladder-sparing trimodality therapy. Potential biomarkers, ongoing clinical trials, and future directions are highlighted. CONCLUSIONS: This guideline embodies the collaborative expertise from all disciplines involved, and provides guidance to further optimize and standardize the management of MIBC.

Genomics models in radiotherapy: From mechanistic to machine learning

Machine learning (ML) provides a broad framework for addressing high-dimensional prediction problems in classification and regression. While ML is often applied for imaging problems in medical physics, there are many efforts to apply these principles to biological data toward questions of radiation biology. Here, we provide a review of radiogenomics modeling frameworks and efforts toward genomically guided radiotherapy. We first discuss medical oncology efforts to develop precision biomarkers. We next discuss similar efforts to create clinical assays for normal tissue or tumor radiosensitivity. We then discuss modeling frameworks for radiosensitivity and the evolution of ML to create predictive models for radiogenomics.

Emerging biomarkers in urothelial carcinoma: Challenges and opportunities

Advanced urothelial carcinoma (UC) is a very important cause of cancer-related morbidity and mortality with, until recently, only a few available therapeutic options. The treatment landscape has dramatically changed in recent years with the introduction of immune checkpoint inhibitors and the development of novel targeted agents, such as erdafitinib, and antibody-drug conjugates, such as enfortumab vedotin. Cost-effective utilization of this rapidly expanding therapeutic armamentarium can be further optimized via the identification and validation of reliable prognostic and predictive biomarkers that inform prognostication and patient selection. In this review, we aim to summarize examples of recent developments in the rapidly expanding field of emerging biomarkers in UC, outlining challenges and opportunities.

Bladder-sparing treatment options in localized muscle-invasive bladder cancer

Introduction: Bladder cancer is the 9th most common cancer in the world and the 4^th and 8th most common cancer diagnosed in men in the United States and United Kingdom respectively. The standard of care for the treatment of MIBC is radical cystectomy. Bladder preserving treatment approaches are emerging for select patients and should be considered strongly in patients who decline a radical cystectomy.Areas covered: In this review we look at the European and American recommended guidelines, the current standard of care, bladder-preserving options in MIBC, trimodal therapy and discuss future developments in the identification of molecular biomarkers that can predict therapeutic outcomes.Expert opinion: We strongly advocate bladder preservation for the right patient with strict criteria for enrolling patients in bladder preservation. The development of a specialized bladder cancer clinic could facilitate the selection of patients to be offered trimodal therapy. We believe that the future of bladder cancer will involve individualized care plans based upon clinical, radiological, endoscopic and molecular assessments.

Precision oncology in urothelial cancer

Genomics-driven, precision medicine has been adopted in virtually every tumour type and underlies the significant advances in cancer management to date. The paradigm shift from the indiscriminate use of chemotherapeutics, to strategies that harness our mechanistic knowledge of cancer biology has led to profound clinical benefit for patients, and will continue to mould present and future treatment approaches. In the realm of urothelial cancer, the present status of precision medicine includes a rich landscape that encompasses molecularly-matched therapy, predictive biomarkers that could help inform response to chemotherapy and immunotherapy, as well as novel strategies such as antibody drug conjugates that exploit the use of target proteins for enhanced tumour killing. Here, we present an overview on these clinically-impactful discoveries in urothelial cancer, discuss the limitations and challenges in the implementation of precision oncology, and offer our vision for its future.

Trimodality Therapy for Muscle-Invasive Bladder Cancer: Recent Advances and Unanswered Questions

PURPOSE OF REVIEW

Bladder-sparing trimodality therapy (TMT) has become an accepted alternative to cystectomy for selected muscle invasive bladder cancer (MIBC) patients unfit for cystectomy or opting for bladder preservation. This review will summarize recent advances in TMT for MIBC.

RECENT FINDINGS

A growing body of literature has emerged which supports the use of TMT. However, its delivery is yet to be standardized. The role of chemotherapy and predictive biomarkers remain to be elucidated. Novel bladder-sparing approaches, drug combinations including immunotherapy and targeted therapies are under investigation in clinical trials, with the goal of ultimately enhancing survival and quality of life outcomes. Recent advances in TMT have made bladder preservation possible for MIBC patients seeking an alternative local therapy to cystectomy. With careful patient selection, TMT offers comparable survival outcomes to cystectomy, and improved quality of life as patients are able to successfully retain their bladder.

Nuclear Factor-κB Overexpression is Correlated with Poor Outcomes after Multimodality Bladder-Preserving Therapy in Patients with Muscle-Invasive Bladder Cancer

The aim of this study was to investigate prognostic molecular targets for selecting patients with muscle-invasive bladder cancer undergoing bladder-preserving therapy. Pretreatment biopsy samples from patients with muscle-invasive bladder cancer receiving trimodality bladder-preserving therapy were analyzed for expression levels of p53, p16, human epidermal growth factor receptor-2 (Her-2), epidermal growth factor receptor (EGFR), nuclear factor-kappa B (NFκB; p65), E-cadherin, matrix metalloproteinase-9 (MMP9), meiotic recombination 11 homolog (MRE11), programmed death-1 ligand (PD-L1), and mismatch repair proteins (MLH1, PMS2, MSH2, and MSH6) by immunohistochemical (IHC) staining. The correlations between these molecular markers with local progression-free survival (LPFS), distant metastasis-free survival (DMFS), and overall survival (OS) were explored. Biopsy samples from 41 out of 60 patients were evaluated using IHC. Univariate analysis revealed that the high expression of NFκB is associated with significantly worse LPFS, DMFS, and OS, and low expression of p16 is associated with significantly lower LPFS. Upon further multivariate analysis including sex, age, stage, and selected unfavorable factors in the model, NFκB and p16 independently remained significant. The investigational in vitro study demonstrated that irradiation induces up-regulation of NFκB signaling. Irradiated bladder cancer cells showed increased invasion capability and clonogenic survival; inhibition of NFκB signaling by an NFκB inhibitor, SC75741, or RNA interference reversed the observed increases. NFκB expression (p65) is associated with prognostic significance for both LPFS and DMFS in patients treated with bladder-preserving therapy, with consistent impact on cell viability of bladder cancer cells. NFκB may be a putative molecular target to help with outcome stratification.

MRE11A Isoform Expression Associated with Outcome Following Radiotherapy in Muscle-Invasive Bladder Cancer does not Alter Cell Survival and DNA Double-Strand Break Repair Following Ionising Radiation

BACKGROUND

DNA double strand breaks are the cytotoxic lesions produced by ionising radiation. Critical for the repair of these lesions is the DNA damage response protein MRE11 which, in a complex with RAD50 and NBS1, mediates DNA damage signalling and double-strand break repair. We previously found the presence of an MRE11 germline single nucleotide polymorphism (SNP), rs1805363 (G > A), to be associated with poor outcome following radiotherapy (RT) and increased expression of MRE11 isoform 2 in a limited panel of bladder cancer cell lines and tumours.

OBJECTIVES

To look for further evidence in support of the SNP/isoform association in a larger panel of germline and tumour samples donated by patients diagnosed with invasive bladder cancer, and to test the hypothesis that bladder cancer cells expressing MRE11 isoform 2 would be more radio resistant than cells expressing MRE11 isoform 1.

METHODS

Germline DNA from 189 patients with invasive bladder cancer (141 T2, 48 T1) was genotyped for the rs1805363 G > A SNP. Loss of heterozygosity was determined by genotyping tumour DNA in 17GA germline patients. The Cancer Genome Atlas was mined to correlate presence of the GA germline genotype with MRE11 isoform expression. We used colony formation assays and γH2AX foci kinetics after ionising radiation in RT112 MRE11 knockdown cells expressing ectopic MRE11 isoform 1 or 2.

RESULTS

Of the 189 germline DNA samples, 22 contained both the A minor allele and G major allele with the remaining wild type containing only the G major allele. LOH was identified in seven of 17 available tumour samples. Tumour MRE11 isoform 2 expression was found to be significantly higher (p = 0.007) in patients's samples containing the A minor allele compared to those with only the G major allele (n = 23). In the TCGA database we found 16% (66 out of 406) of bladder tumours heterozygous for the SNP and only two homozygous, and a significant relative increase of isoform 2 usage (p = 0.017). We identified no significant difference in radio sensitivity between bladder cancer cells expressing either MRE11 isoform.

CONCLUSIONS

In this study the MRE11 isoform 2 was not found to be associated with increased cellular sensitivity to radiation. We conclude that the previously reported association between the germline rs1805363 SNP and poor survival in MIBC patients following RT is unlikely to be related to the DNA damage response function of MRE11 isoform 2.

MRE11 as a Predictive Biomarker of Outcome After Radiation Therapy in Bladder Cancer

PURPOSE

Organ-confined muscle-invasive bladder cancer is treated with cystectomy or bladder preservation techniques, including radiation therapy. There are currently no biomarkers to inform management decisions and aid patient choice. Previously we showed high levels of MRE11 protein, assessed by immunohistochemistry (IHC), predicted outcome after radiation therapy, but not cystectomy. Therefore, we sought to develop the MRE11 IHC assay for clinical use and define its relationship to clinical outcome in samples from 2 major clinical trials.

METHODS AND MATERIALS

Samples from the BCON and BC2001 randomized controlled trials and a cystectomy cohort were stained using automated IHC methods and scored for MRE11 in 3 centers in the United Kingdom.

RESULTS

Despite step-wise creation of scoring cards and standard operating procedures for staining and interpretation, there was poor intercenter scoring agreement (kappa, 0.32; 95% confidence interval, 0.17-0.47). No significant associations between MRE11 scores and cause-specific survival were identified in BCON (n = 132) and BC2001 (n = 221) samples. Reoptimized staining improved agreement between scores from BCON tissue microarrays (n = 116), but MRE11 expression was not prognostic for cause-specific survival.

CONCLUSIONS

Manual IHC scoring of MRE11 was not validated as a reproducible biomarker of radiation-based bladder preservation success. There is a need for automated quantitative methods or a reassessment of how DNA-damage response relates to clinical outcomes.

Molecular biomarkers in bladder preservation therapy for muscle-invasive bladder cancer

Although muscle-invasive bladder cancer is commonly treated with radical cystectomy, a standard alternative is bladder preservation therapy, consisting of maximum transurethral bladder tumour resection followed by radiotherapy with concurrent chemotherapy. Although no successfully completed randomised comparisons are available, the two treatment paradigms seem to have similar long-term outcomes; however, clinicopathologic parameters can be insufficient to provide clear guidance in the selection of one treatment over the other. Recent advances in the molecular understanding of bladder cancer have led to the identification of new predictive biomarkers that ultimately might help guide the tailored selection of therapy on the basis of the intrinsic biology of the tumour. In this Review, we discuss the existing evidence for molecular alterations and genomic signatures as prognostic or predictive biomarkers for bladder preservation therapy. If validated in prospective clinical trials, such biomarkers could enable the identification of subgroups of patients who are more likely to benefit from one treatment over another, and guide the use of combination therapies that include other modalities, such as immunotherapy, which might act synergistically with radiotherapy.

Organ preservation in bladder cancer: an opportunity for truly personalized treatment

Radical treatment of many solid tumours has moved from surgery to multimodal organ preservation strategies combining systemic and local treatments. Trimodality bladder-preserving treatment (TMT) comprises maximal transurethral resection of the bladder tumour followed by radiotherapy and concurrent radiosensitizing treatment, thereby sparing the urinary bladder. From the patient's perspective, the choice of maintaining quality of life without a negative effect on the chances of cure and long-term survival is attractive. In muscle-invasive bladder cancer (MIBC), the evidence shows comparable clinical outcomes between patients undergoing radical cystectomy and TMT. Despite this evidence, many patients continue to be offered radical surgery as the standard-of-care treatment. Improvements in radiotherapy techniques with adaptive radiotherapy and advances in imaging translate to increases in the accuracy of treatment delivery and reductions in long-term toxicities. With the advent of novel biomarkers promising improved prediction of treatment response, stratification of patients for different treatments on the basis of tumour biology could soon be a reality. The future of oncological treatment lies in personalized medicine with the combination of technological and biological advances leading to truly bespoke management for patients with MIBC.

Formidable Scenarios in Urothelial and Variant Cancers of the Urinary Tract

Diagnostic and therapeutic challenges in the field of bladder and upper tract cancers provide opportunities for multidisciplinary care. Urothelial cancers make up the majority of the histologic subtype of bladder and upper tract cancers. Although the existence of variant histology, nonurothelial cancers, and urethral cancers is rare, these cancers pose a challenging clinical dilemma given the lack of well-defined consensus treatment guidelines. This review focuses on key issues of treatment: cisplatin ineligibility with emphasis on the definition, nuances of chemotherapy and frontline immune checkpoint inhibitor therapy, use of radiation in bladder-preservation strategies, upper tract urothelial cancer management, and highlights of urothelial variants and nonurothelial tumors and management.

MicroRNA Biomarkers for Patients With Muscle-Invasive Bladder Cancer Undergoing Selective Bladder-Sparing Trimodality Treatment

PURPOSE

Trimodality therapy with maximal transurethral resection of bladder tumor and definitive chemoradiation reserving cystectomy for salvage of local recurrence is an accepted treatment alternative to upfront cystectomy for selected patients with muscle-invasive bladder cancer. There is a need for molecular biomarkers to predict which patients will respond to bladder preservation therapy.

METHODS AND MATERIALS

We sought to identify biomarkers with the ability to predict response to chemoradiation and survival after selective bladder preservation therapy in a cohort of 40 patients using a microRNA profiling approach. In vitro experiments were performed using transitional cell carcinoma lines CRL1749, HTB5, and HTB4.

RESULTS

We identified a panel of microRNAs associated with overall survival in our bladder preservation cohort and in the TCGA cohort. We also identified several microRNAs, including miR-23a and miR-27a, microRNAs of the miR-23a cluster, to be suggestively associated with complete response to chemoradiation therapy. The microRNAs were significantly associated with overall survival in The Cancer Genome Atlas cohort. In vitro studies suggest that the functional roles of miR-23a and miR-27a involve targeting the SFRP1 protein, a negative regulator of the Wnt signaling pathway. The upregulation of β-catenin in the Wnt signaling pathway mediated proliferation, migration, invasion, and sensitivity to radiation and cisplatin treatment in bladder cancer cells.

CONCLUSIONS

Our results indicate that miR-23a and miR-27a act as oncomirs, and once independently validated, they may help appropriately triage selected bladder cancer patients to individualize treatment.

Developing Predictive or Prognostic Biomarkers for Charged Particle Radiotherapy

The response to radiotherapy can vary greatly among individuals, even though advances in technology allow for the highly localized placement of therapeutic doses of radiation to a tumor. This variability in patient response to radiation is biologically driven, but the individuality of tumor and healthy tissue biology are not used to create individual treatment plans. Biomarkers of radiosensitivity, whether intrinsic or from hypoxia, would move radiation oncology from precision medicine to precise, personalized medicine. Charged particle radiotherapy allows for even greater dose conformity, but the biological advantages of charged particle radiotherapy have not yet been cultivated. The development of biomarkers that would drive biologically based clinical trials, identify patients for whom charged particles are most appropriate, or aid in particle-selection strategies could be envisioned with appropriate biomarkers. Initially, biomarkers for low-linear energy transfer (LET) radiation responses should be tested against charged particles. Biomarkers of tumor radioresistance to low-LET radiations could be used to identify patients for whom the enhanced relative biological effectiveness (RBE) of charged particles would be more effective compared with low-LET radiations and those for whom specific DNA-repair inhibitors, in combination with charged particles, may also be appropriate. Furthermore, heavy charged particles can overcome the radioresistance of hypoxic tumors when used at the appropriate LET. Biomarkers for hypoxia could identify hypoxic tumors and, in combination with imaging, define hypoxic regions of a tumor for specific ion selection. Moreover, because of the enhanced RBE for charged particles, the risk for adverse healthy tissue effects may be greater, even though charged particles have greater tumor conformality. There are many validated healthy-tissue biomarkers available to test against charged particle exposures. Lastly, newer biological techniques, as well as newer bioinformatic and computational methods, are rapidly changing the landscape for biomarker identification, validation, and clinical trial design.

Bladder Preservation Therapy: Review of Literature and Future Directions of Trimodal Therapy

PURPOSE OF THE REVIEW

This review targets the latest literature on bladder preservation therapy with emphasis on trimodal therapy (TMT), highlighting its role in the management of muscle invasive bladder cancer (MIBC) and outlining future directions in bladder preservation research.

RECENT FINDINGS

TMT is the most promising bladder preservation treatment modality. Comparable results to contemporary radical cystectomy series are seen in properly selected patients. A multidisciplinary team approach is critical in the management of these patients. Future research is directed at the integration of immunotherapy into the treatment protocol. TMT, involving maximal transurethral resection followed by chemoradiation, is an attractive alternative to radical cystectomy with urinary diversion in carefully selected patients with muscle invasive disease. In the absence of randomized trial (RCT), comparison between TMT and cystectomy, based on retrospective data from large centers, suggests comparable oncological outcomes, with a favorable impact on quality of life.

Emerging biomarkers for the combination of radiotherapy and immune checkpoint blockers

Over the past few years, multiple immune checkpoint blockers (ICBs) have achieved unprecedented clinical success and have been approved by regulatory agencies for the treatment of an increasing number of malignancies. However, only a limited fraction of patients responds to ICBs employed as a standalone intervention, calling for the development of combinatorial regimens. Radiation therapy (RT) stands out as a very promising candidate for this purpose. Indeed, RT mediates antineoplastic effects not only by cytotoxic and cytostatic mechanisms, but also by modulating immunological functions, both locally (within the irradiated field) and systemically. As combinatorial regimens involving RT and ICBs are being developed and clinically tested at an accelerating pace, it is paramount to identify biomarkers that reliably predict the likelihood of individual patients to respond. Here, we discuss emerging biomarkers that may potentially predict the response of cancer patients to RT plus ICBs.

The role of biomarkers in bladder preservation management of muscle-invasive bladder cancer

PURPOSE

Patients with localized muscle-invasive bladder cancer (MIBC) can choose to undergo either neoadjuvant chemotherapy followed by radical cystectomy or radiation therapy-based bladder preservation treatment modality with subsequent close cystoscopic surveillance with salvage cystectomy reserved for patients with evidence of local disease recurrence. At the present time, the decision regarding bladder-directed local therapy for MIBC is based on physicians' and patients' preferences, and does not take into account tumor biology. Predictive biomarkers, once validated, could offer a more patient-centered and biology-driven selection of bladder-directed therapies.

METHODS

We provide a narrative review of clinical data pertaining to the biomarkers in bladder preservation management of MIBC.

RESULTS

There are currently no validated and clinically used biological markers used for stratification of radical bladder treatment and selection of bladder-preserving therapies. This article summarizes biomarkers that could have a potential clinical utility-PD-L1, molecular subtypes, Ki-67, MRE-11 and markers of hypoxia-and offers a hypothetical pathway model for a marker-driven precision management of medically operable patients with a newly diagnosed MIBC.

CONCLUSION

When selecting the optimal cancer treatment, both patient and tumor factors need to be considered. Once validated, biological markers will help clinicians tailor the management of MIBC to individual patients.

Overexpression of the MRE11-RAD50-NBS1 (MRN) complex in rectal cancer correlates with poor response to neoadjuvant radiotherapy and prognosis

BACKGROUND

The MRE11/RAD50/NBS1 (MRN) complex plays an essential role in detecting and repairing double-stranded breaks, and thus the potential roles of MRE11, RAD50 and NBS1 proteins in the pathogenesis of various cancers is the subject of investigation. This study was aimed at assessing the three-protein panel of MRN complex subunits as a potential radiosensitivity marker and evaluating the prognostic and clinicopathological implications of MRN expression in rectal cancer.

METHODS

Samples from 265 rectal cancer patients treated with surgery and adjuvant chemoradiotherapy, including samples from 55 patients who were treated with neoadjuvant radiotherapy between 2000 and 2011, were analyzed. Expression of MRN complex proteins in tissue samples was determined by immunohistochemistry. Univariate and multivariate analyses were carried out to identify clinicopathological characteristics that are associated with the MRN three-protein panel expression in rectal cancer samples.

RESULTS

In Kaplan-Meier survival analyses, we found that high level expression of MRN complex proteins in postoperative samples was associated with poor disease-free (p = 0.021) and overall (P = 0.002) survival. Interestingly, high MRN expression also correlated with poor disease-free (P = 0.047) and overall (P = 0.024) survival in the neoadjuvant radiotherapy subgroup. In multivariate analysis, combined MRN expression (hazard ratio = 2.114, 95% confidence interval 1.096-4.078, P = 0.026) and perineural invasion (hazard ratio = 2.160, 95% confidence interval 1.209-3.859, P = 0.009) were significantly associated with a worse disease-free survival.

CONCLUSIONS

Expression levels of MRN complex proteins significantly predict disease-free survival in rectal cancer patients, including those treated with neoadjuvant radiotherapy, and may have value in the management of these patients.

Advances in risk stratification of bladder cancer to guide personalized medicine

Bladder cancer is a heterogeneous disease that poses unique challenges to the treating clinician. It can be limited to a relatively indolent papillary tumor with low potential for progression beyond this stage to muscle-invasive disease prone to distant metastasis. The former is best treated as conservatively as possible, whereas the latter requires aggressive surgical intervention with adjuvant therapies in order to provide the best clinical outcomes. Risk stratification traditionally uses clinicopathologic features of the disease to provide prognostic information that assists in choosing the best therapy for each individual patient. For bladder cancer, this informs decisions regarding the type of intravesical therapy that is most appropriate for non-muscle-invasive disease or whether or not to administer neoadjuvant chemotherapy prior to radical cystectomy. More recently, tumor genetic sequencing data have been married to clinical outcomes data to add further sophistication and personalization. In the next generation of risk classification, we are likely to see the inclusion of molecular subtyping with specific treatment considerations based on a tumor’s mutational profile.

Radiotherapy for High-grade T1 Bladder Cancer

Radiotherapy is rarely used for T1 bladder cancer. We discuss the potential reasons for this, the current evidence, and make suggestions for future research. PATIENT SUMMARY: Despite its success in muscle-invasive disease, radiotherapy is rarely used for non-muscle-invasive bladder cancer. We discuss the current evidence and suggest that, with further research, radiotherapy holds much promise as a bladder-preserving strategy.

Harnessing citizen science through mobile phone technology to screen for immunohistochemical biomarkers in bladder cancer

BACKGROUND

Immunohistochemistry (IHC) is often used in personalisation of cancer treatments. Analysis of large data sets to uncover predictive biomarkers by specialists can be enormously time-consuming. Here we investigated crowdsourcing as a means of reliably analysing immunostained cancer samples to discover biomarkers predictive of cancer survival.

METHODS

We crowdsourced the analysis of bladder cancer TMA core samples through the smartphone app 'Reverse the Odds'. Scores from members of the public were pooled and compared to a gold standard set scored by appropriate specialists. We also used crowdsourced scores to assess associations with disease-specific survival.

RESULTS

Data were collected over 721 days, with 4,744,339 classifications performed. The average time per classification was approximately 15 s, with approximately 20,000 h total non-gaming time contributed. The correlation between crowdsourced and expert H-scores (staining intensity × proportion) varied from 0.65 to 0.92 across the markers tested, with six of 10 correlation coefficients at least 0.80. At least two markers (MRE11 and CK20) were significantly associated with survival in patients with bladder cancer, and a further three markers showed results warranting expert follow-up.

CONCLUSIONS

Crowdsourcing through a smartphone app has the potential to accurately screen IHC data and greatly increase the speed of biomarker discovery.

Multidisciplinary Management of Muscle-Invasive Bladder Cancer: Current Challenges and Future Directions

The treatment of muscle-invasive bladder cancer (MIBC) is complex and requires a multidisciplinary collaboration among surgery, radiation, and medical oncology. Although neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) and lymph node dissection has been considered the standard treatment for MIBC, many patients are unfit for surgery or cisplatin-ineligible, and considerations for bladder-preservation strategies not only are increasingly recognized as optimal treatment alternatives, but also should feature in the range of management options presented to patients at the time of diagnosis. Apart from chemotherapy, immunotherapy has also been used with success in locally advanced and metastatic bladder cancer and is moving into the MIBC space. Prospective studies addressing trends in management that span systemic, surgical, and radiation options for patients are discussed in this article.

Applying Precision Oncology Principles in Radiation Oncology

Radiation therapy is a critical component in the curative management of many solid tumor types, and advances in radiation delivery techniques during the past decade have led to improved disease control and quality of life for patients. During the same period, remarkable advances have also been made in understanding the genomic landscape of tumors; however, treatment decisions in radiation oncology continue to depend primarily on clinical and histopathologic characteristics rather than on the genetic features of the tumor or the patient. With the development of novel genomic techniques and their increasing use in clinical practice, radiation oncology is uniquely positioned to leverage these advances to identify novel biomarkers that could inform radiation dose, field, and the use of concurrent systemic agents. Here, we summarize efforts to use genomic techniques to guide radiation decisions, and we highlight some of the current opportunities and challenges that exist in attempting to apply precision oncology principles in radiation oncology.

Genetic variants in the histone methylation and acetylation pathway and their risks in eight types of cancers

OBJECTIVES

The histone methylation and acetylation pathway genes regulate cell growth and survival. Aberrations in this pathway are implicated in a variety of cancers. This study aimed to identify germline genetic variants in histone methylation and acetylation pathway genes that may contribute to risk in eight types of cancers and to explore the relation between the whole pathway and their risks in these types of cancers.

METHODS

Germline genetic variants in 89 genes in the histone methylation and acetylation pathway were explored. Gene-based and pathway-based associations with eight types of cancers were analyzed using logistic regression models and the permutation-based adaptive rank-truncated product method, respectively.

RESULTS

Gene-level associations revealed that genetic variants in 45 genes were significantly associated with the risk of cancer. The total histone methylation and acetylation pathway was significantly associated with the risk of esophageal squamous cell carcinoma (P = 0.0492) and prostate (P = 0.0038), lung (P = 0.00015), and bladder cancer (P = 0.00135), but not with breast (P = 0.182), pancreatic (P = 0.336) and gastric cancer (P = 0.347) and renal cell carcinoma (P =0.828).

CONCLUSIONS

Our study suggested there is an association between germline genetic variation at the overall histone methylation and acetylation pathway level and some individual genes with cancer risk. Further studies are needed to validate these relations and to explore relative mechanisms.

Molecular Prognostication in Bladder Cancer

Clinical outcomes for patients with bladder cancer have largely remained unchanged over the last three decades despite improvements in surgical techniques, perioperative therapies, and postoperative management. Current management still heavily relies on pathologic staging that does not always reflect an individual patient's risk. The genesis and progression of bladder cancer is now increasingly recognized as being a result of alterations in several pathways that affect the cell cycle, apoptosis, cellular signaling, gene regulation, immune modulation, angiogenesis, and tumor cell invasion. Multiplexed assessment of biomarkers associated with alterations in these pathways offers novel insights into tumor behavior while identifying panels that are capable of reproducibly predicting patient outcomes. Future management of bladder cancer will likely incorporate such prognostic molecular models for risk stratification and treatment personalization.

Clinical and patient-reported outcomes of SPARE - a randomised feasibility study of selective bladder preservation versus radical cystectomy

OBJECTIVES

To test the feasibility of a randomised trial in muscle-invasive bladder cancer (MIBC) and compare outcomes in patients who receive neoadjuvant chemotherapy followed by radical cystectomy (RC) or selective bladder preservation (SBP), where definitive treatment [RC or radiotherapy (RT)] is determined by response to chemotherapy.

PATIENTS AND METHODS

SPARE is a multicentre randomised controlled trial comparing RC and SBP in patients with MIBC staged T2-3 N0 M0, fit for both treatment strategies and receiving three cycles of neoadjuvant chemotherapy. Patients were randomised between RC and SBP before a cystoscopy after cycle three of neoadjuvant chemotherapy. Patients with ≤T1 residual tumour received a fourth cycle of neoadjuvant chemotherapy in both groups, followed by radical RT in the SBP group and RC in in the RC group; non-responders in both groups proceeded immediately to RC following cycle three. Feasibility study primary endpoints were accrual rate and compliance with assigned treatment strategy. The phase III trial was designed to demonstrate non-inferiority of SBP in terms of overall survival (OS) in patients whose tumours responded to neoadjuvant chemotherapy. Secondary endpoints included patient-reported quality of life, clinician assessed toxicity, loco-regional recurrence-free survival, and rate of salvage RC after SBP.

RESULTS

Trial recruitment was challenging and below the predefined target with 45 patients recruited in 30 months (25 RC; 20 SBP). Non-compliance with assigned treatment strategy was frequent, six of the 25 patients (24%) randomised to RC received RT. Long-term bladder preservation rate was 11/15 (73%) in those who received RT per protocol. OS survival was not significantly different between groups.

CONCLUSIONS

Randomising patients with MIBC between RC and SBP based on response to neoadjuvant chemotherapy was not feasible in the UK health system. Strong clinician and patient preferences for treatments impacted willingness to undergo randomisation and acceptance of treatment allocation. Due to the few participants, firm conclusions about disease and toxicity outcomes cannot be drawn.