Bcl-2 expression identifies patients with advanced bladder cancer treated by radiotherapy who benefit from neoadjuvant chemotherapy

Protein-Based Predictive Biomarkers to Personalize Neoadjuvant Therapy for Bladder Cancer-A Systematic Review of the Current Status

The clinical outcome of patients with muscle-invasive bladder cancer (MIBC) is poor despite the approval of neoadjuvant chemotherapy or immunotherapy to improve overall survival after cystectomy. MIBC subtypes, immune, transcriptome, metabolomic signatures, and mutation burden have the potential to predict treatment response but none have been incorporated into clinical practice, as tumor heterogeneity and lineage plasticity influence their efficacy. Using the PRISMA statement, we conducted a systematic review of the literature, involving 135 studies published within the last five years, to identify studies reporting on the prognostic value of protein-based biomarkers for response to neoadjuvant therapy in patients with MIBC. The studies were grouped based on biomarkers related to molecular subtypes, cancer stem cell, actin-cytoskeleton, epithelial-mesenchymal transition, apoptosis, and tumor-infiltrating immune cells. These studies show the potential of protein-based biomarkers, especially in the spatial context, to reduce the influence of tumor heterogeneity on a biomarker's prognostic capability. Nevertheless, currently, there is little consensus on the methodology, reagents, and the scoring systems to allow reliable assessment of the biomarkers of interest. Furthermore, the small sample size of several studies necessitates the validation of potential prognostic biomarkers in larger multicenter cohorts before their use for individualizing neoadjuvant therapy regimens for patients with MIBC.

Predictors of response to neoadjuvant therapy in urothelial cancer

Neoadjuvant cisplatin-based chemotherapy (NACC) followed by radical cystectomy is the standard treatment for localized muscle-invasive bladder cancer (MIBC). Patients who achieve a complete pathological response following NACC have better overall survival than those with residual disease. However, a subset of patients does not derive benefit from NACC while experiencing chemotherapy-related side effects that may delay cystectomy, which can be detrimental. There is a need for predictive and prognostic biomarkers to better stratify patients who will derive benefits from NACC. This review summarizes the currently available literature on various predictors of response to neoadjuvant chemotherapy. Covered predictors include clinical factors, treatment regimens (including chemotherapy and immunotherapy), histological predictors, and molecular predictors such as DNA repair genes, p53, FGFR3, ERBB2, Bcl-2, EMMPRIN, survivin, choline-phosphate cytidylyltransferase-α, epigenetic markers, immunological markers, other molecular predictors and gene expression profiling. Further, we elaborate on the potential role of neoadjuvant immunotherapy and the correlative biomarkers of response.

Updates on the Pivotal Roles of Mitochondria in Urothelial Carcinoma

Mitochondria are important organelles responsible for energy production, redox homeostasis, oncogenic signaling, cell death, and apoptosis. Deregulated mitochondrial metabolism and biogenesis are often observed during cancer development and progression. Reports have described the crucial roles of mitochondria in urothelial carcinoma (UC), which is a major global health challenge. This review focuses on research advances in the role of mitochondria in UC. Here, we discuss the pathogenic roles of mitochondria in UC and update the mitochondria-targeted therapies. We aim to offer a better understanding of the mitochondria-modulated pathogenesis of UC and hope that this review will allow the development of novel mitochondria-targeted therapies.

The value of BCL2 and CK20 expression in predicting behavioral patterns of bladder cancer, a cross sectional study

Background

Several biomarkers have been investigated to predict the biological behavior and prognosis of patients with bladder cancer. We evaluated the role of two important markers including BCL2 and CK20 in evaluating the biological behavior of bladder tumors.

Methods

This cross-sectional study was performed on 30 patients suffering from one of the neoplasms of the bladder. To evaluate the expression of BCL2 and CK20 markers, the neoplastic tissue sample was initially extracted and immunohistochemistry staining was employed.

Results

The positivity of CK20 and BCL2 in the patients’ specimens was found to be 53.3% and 10.0%, respectively. There was no association between CK20 and BCL2 expressions and tumor size, tumor stage, or tumor-related vascular invasion, but BCL2 expression was shown to be higher in the low-grade specimens, while the expression rate of CK20 was found to be significantly higher in high grade samples.

Conclusion

Evaluation of the expression of CK20 and BCL2 markers can be very valuable in predicting bladder tumor grade.

•

Bladder cancer is the most common malignant tumor in the urinary tract and is the ninth most common cancer in the world.

•

Identification of proliferative activity in tumors may be useful for predicting its biological behavior.

•

Evaluation of the expression of CK20 and BCL2 markers can be very valuable in predicting bladder tumor grade.

Progress in the development of tissue-based biomarkers for urothelial cancer

INTRODUCTION

As the understanding of molecular mechanisms of bladder cancer advances, molecularly-guided precision medicine becomes increasingly relevant. Biomarkers play a critical role in this setting, predicting treatment response and identifying candidates for targeted therapies.

AREAS COVERED

Current literature on biomarkers in their role in disease prognosis, and response to neoadjuvant and adjuvant therapies. In non-muscle invasive bladder cancer, particular focus is on markers of disease progression, and response to intravesical therapy. In muscle invasive and advanced bladder cancer, particular emphasis is on markers associated with neoadjuvant chemotherapy, as well as systemic immunotherapy. We discuss current shortcomings and pitfalls in contemporary markers, and future avenues of prospective research.

EXPERT OPINION

The focus on biomarkers has moved from immunohistochemical analysis and tumor-related phenotypic changes to examining genetic alterations. Single marker analysis has been shown to be insufficient in predicting both disease course and response to therapy, and studies have shifted towards examining marker combinations and genetic classifiers. Ultimately, significant progress in implementing biomarkers into clinical guidelines remains elusive, largely due to lack of prospective studies in well-defined patient cohorts and with clinically-meaningful endpoints. Until then, despite their promising value, tissue markers should be limited to experimental settings and clinical trials.

Obatoclax, a BH3 Mimetic, Enhances Cisplatin-Induced Apoptosis and Decreases the Clonogenicity of Muscle Invasive Bladder Cancer Cells via Mechanisms That Involve the Inhibition of Pro-Survival Molecules as Well as Cell Cycle Regulators

Several studies by our group and others have determined that expression levels of Bcl-2 and/or Bcl-xL, pro-survival molecules which are associated with chemoresistance, are elevated in patients with muscle invasive bladder cancer (MI-BC). The goal of this study was to determine whether combining Obatoclax, a BH3 mimetic which inhibits pro-survival Bcl-2 family members, can improve responses to cisplatin chemotherapy, the standard of care treatment for MI-BC. Three MI-BC cell lines (T24, TCCSuP, 5637) were treated with Obatoclax alone or in combination with cisplatin and/or pre-miR-34a, a molecule which we have previously shown to inhibit MI-BC cell proliferation via decreasing Cdk6 expression. Proliferation, clonogenic, and apoptosis assays confirmed that Obatoclax can decrease cell proliferation and promote apoptosis in a dose-dependent manner. Combination treatment experiments identified Obatoclax + cisplatin as the most effective treatment. Immunoprecipitation and Western analyses indicate that, in addition to being able to inhibit Bcl-2 and Bcl-xL, Obatoclax can also decrease cyclin D1 and Cdk4/6 expression levels. This has not previously been reported. The combined data demonstrate that Obatoclax can inhibit cell proliferation, promote apoptosis, and significantly enhance the effectiveness of cisplatin in MI-BC cells via mechanisms that likely involve the inhibition of both pro-survival molecules and cell cycle regulators.

Is Bcl-2 a predictive marker of neoadjuvant chemotherapy response in patients with urothelial bladder cancer undergoing radical cystectomy?

Background: Response to neoadjuvant cisplatin treatment in bladder cancer has been linked to expression of Bcl-2 protein by cancer cells. The objective of this study was to test Bcl-2 as a predictive marker of neoadjuvant cisplatin chemotherapy response in a patient cohort from randomized cystectomy trials. Methods: Tumor samples were taken from 247 patients with T2-T4 bladder cancer enrolled in two randomized trials comparing cystectomy with or without neoadjuvant chemotherapy. Tissue microarrays from pre-intervention transurethral resection specimens were assessed for Bcl-2 protein status by immunohistochemistry. Extension of staining above 10% was regarded as positive. Downstaging and survival ratios in relation to Bcl-2 immunoreactivity and neoadjuvant chemotherapy utilization were calculated using the log rank test and multivariate Cox proportional hazards regression analyses. Results: Bcl-2 expression was positive in 38% and negative in 62% of the 236 evaluable patients. Bcl-2 negative patients receiving neoadjuvant chemotherapy had a significant increase in survival (p = 0.009), while Bcl-2 positive patients showed no difference (p = 0.4). However, the interaction variable between neoadjuvant chemotherapy and biomarker status was not significant (p = 0.38). When the prognostic value was assessed in the no-chemotherapy group, 5-year overall survival times were significantly better among Bcl-2 positive patients than among Bcl-2 negative patients (42 months vs 33 months, p = 0.04), but again Bcl-2 status did not remain independent when other factors were adjusted. Also, in a multivariate analysis with all patients, Bcl-2 was not significant. Conclusions: Bcl-2 status is not an independent predictor of neoadjuvant cisplatin chemotherapy response and is not prognostic in muscle-invasive bladder cancer.

Cross Talk Between Cellular Redox State and the Antiapoptotic Protein Bcl-2

SIGNIFICANCE

B cell lymphoma-2 (Bcl-2) was discovered over three decades ago and is the prototype antiapoptotic member of the Bcl-2 family that comprises proteins with contrasting effects on cell fate. First identified as a consequence of chromosomal translocation (t 14:18) in human lymphoma, subsequent studies have revealed mutations and/or gene copy number alterations as well as post-translational modifications of Bcl-2 in a variety of human cancers. The canonical function of Bcl-2 is linked to its ability to inhibit mitochondrial membrane permeabilization, thereby regulating apoptosome assembly and activation by blocking the cytosolic translocation of death amplification factors. Of note, the identification of specific domains within the Bcl-2 family of proteins (Bcl-2 homology domains; BH domains) has not only provided a mechanistic insight into the various interactions between the member proteins but has also been the impetus behind the design and development of small molecule inhibitors and BH3 mimetics for clinical use. Recent Advances: Aside from its role in maintaining mitochondrial integrity, recent evidence provides testimony to a novel facet in the biology of Bcl-2 that involves an intricate cross talk with cellular redox state. Bcl-2 overexpression modulates mitochondrial redox metabolism to create a "pro-oxidant" milieu, conducive for cell survival. However, under states of oxidative stress, overexpression of Bcl-2 functions as a redox sink to prevent excessive buildup of reactive oxygen species, thereby inhibiting execution signals. Emerging evidence indicates various redox-dependent transcriptional changes and post-translational modifications with different functional outcomes.

CRITICAL ISSUES

Understanding the complex interplay between Bcl-2 and the cellular redox milieu from the standpoint of cell fate signaling remains vital for a better understanding of pathological states associated with altered redox metabolism and/or aberrant Bcl-2 expression.

FUTURE DIRECTIONS

Based on its canonical functions, Bcl-2 has emerged as a potential druggable target. Small molecule inhibitors of Bcl-2 and/or other family members with similar function, as well as BH3 mimetics, are showing promise in the clinic. The emerging evidence for the noncanonical activity linked to cellular redox metabolism provides a novel avenue for the design and development of diagnostic and therapeutic strategies against cancers refractory to conventional chemotherapy by the overexpression of this prosurvival protein.

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.

Pharmacogenomic considerations in the treatment of muscle-invasive bladder cancer

Recent advances in next-generation sequencing techniques have greatly improved our understanding of the genomic alterations in bladder cancer. Cisplatin-based chemotherapy provides a viable treatment option in the neoadjuvant, adjuvant and metastatic setting in a selected group of patients, but chemoresistance is a major problem. The underlying mechanisms of treatment resistance are poorly understood and elucidating these pathways will subsequently lead to improved patient selection, less unnecessary drug-related toxicity, improved patient outcome and decreased healthcare costs. This review provides an overview of mechanisms of chemoresistance and describes the current knowledge on how the genomic landscape influences therapy outcome in muscle-invasive bladder cancer patients.

Molecular biomarkers to predict response to neoadjuvant chemotherapy for bladder cancer

Cystectomy is the gold standard for treatment of localized muscle-invasive bladder cancer. However, about 50% of patients develop metastases within 2years after cystectomy and subsequently die for the disease. Neoadjuvant cisplatin-based chemotherapy before cystectomy improves the overall survival in patients with muscle-invasive bladder cancer, and pathological response to neoadjuvant treatment (downstaging to ⩽pT1 at cystectomy) is a strong predictor of better disease-specific survival. Nevertheless, some patients do not benefit from neoadjuvant therapy. The identification of reliable biomarkers that could enable the clinicians to identify patients who will really benefit from neoadjuvant chemotherapy is a major issue. This approach could lead to individualized therapy, in order to optimize the chance of response, avoiding the impact of neoadjuvant treatment on quality of life and the delay of cystectomy in non-responder patients. However, no molecular predictive biomarkers have shown clinical utility. This paper aims to review currently available data about biomarkers predictive of response to neoadjuvant chemotherapy in muscle-invasive bladder cancer.

Molecular substratification of bladder cancer: moving towards individualized patient management

Despite advances in surgical techniques, perioperative therapies and postoperative management, outcomes for patients with bladder cancer have largely remained unchanged. Current management of bladder cancer still relies on pathologic staging that does not always reflect the risk for an individual patient. Studies assessing molecular alterations in individual tumors are offering insights into the myriad of cellular pathways that are deregulated in bladder tumorigenesis and progression. Alterations in pathways involved in cell-cycle regulation, apoptosis, cell signaling, angiogenesis and tumor-cell invasion have been shown to influence disease behavior. High-throughput assays are now allowing multiplexed assessment of biomarker alterations, thereby enabling characterization of novel molecular subtypes of bladder cancer. Such approaches have also been used for discovery and validation of robust prognostic molecular signatures. The future of bladder cancer management will rely on the use of validated multimarker panels for risk stratification, optimal surgical management, and theranostic strategies to identify and target specific alterations in individual tumors.

Chemoresistance is associated with increased cytoprotective autophagy and diminished apoptosis in bladder cancer cells treated with the BH3 mimetic (-)-Gossypol (AT-101)

Background

Acquired resistance to standard chemotherapy causes treatment failure in patients with metastatic bladder cancer. Overexpression of pro-survival Bcl-2 family proteins has been associated with a poor chemotherapeutic response, suggesting that Bcl-2-targeted therapy may be a feasible strategy in patients with these tumors. The small-molecule pan-Bcl-2 inhibitor (−)-gossypol (AT-101) is known to induce apoptotic cell death, but can also induce autophagy through release of the pro-autophagic BH3 only protein Beclin-1 from Bcl-2. The potential therapeutic effects of (−)-gossypol in chemoresistant bladder cancer and the role of autophagy in this context are hitherto unknown.

Methods

Cisplatin (5637^rCDDP¹⁰⁰⁰, RT4^rCDDP¹⁰⁰⁰) and gemcitabine (5637^rGEMCI²⁰, RT4^rGEMCI²⁰) chemoresistant sub-lines of the chemo-sensitive bladder cancer cell lines 5637 and RT4 were established for the investigation of acquired resistance mechanisms. Cell lines carrying a stable lentiviral knockdown of the core autophagy regulator ATG5 were created from chemosensitive 5637 and chemoresistant 5637^rGEMCI²⁰ and 5637^rCDDP¹⁰⁰⁰ cell lines. Cell death and autophagy were quantified by FACS analysis of propidium iodide, Annexin and Lysotracker staining, as well as LC3 translocation.

Results

Here we demonstrate that (−)-gossypol induces an apoptotic type of cell death in 5637 and RT4 cells which is partially inhibited by the pan-caspase inhibitor z-VAD. Cisplatin- and gemcitabine-resistant bladder cancer cells exhibit enhanced basal and drug-induced autophagosome formation and lysosomal activity which is accompanied by an attenuated apoptotic cell death after treatment with both (−)-gossypol and ABT-737, a Bcl-2 inhibitor which spares Mcl-1, in comparison to parental cells. Knockdown of ATG5 and inhibition of autophagy by 3-MA had no discernible effect on apoptotic cell death induced by (−)-gossypol and ABT-737 in parental 5637 cells, but evoked a significant increase in early apoptosis and overall cell death in BH3 mimetic-treated 5637^rGEMCI²⁰ and 5637^rCDDP¹⁰⁰⁰ cells.

Conclusions

Our findings show for the first time that (−)-gossypol concomitantly triggers apoptosis and a cytoprotective type of autophagy in bladder cancer and support the notion that enhanced autophagy may underlie the chemoresistant phenotype of these tumors. Simultaneous targeting of Bcl-2 proteins and the autophagy pathway may be an efficient new strategy to overcome their “autophagy addiction” and acquired resistance to current therapy.

Biomarker in Cisplatin-Based Chemotherapy for Urinary Bladder Cancer

The treatment of metastasized bladder cancer has been evolving during recent years. Cisplatin based chemotherapy combinations are still gold standard in the treatment of advanced and metastasized bladder cancer. But new therapies are approaching. Based to this fact biological markers will become more important for decisions in bladder cancer treatment. A systematic MEDLINE search of the key words "cisplatin", "bladder cancer", "DNA marker", "protein marker", "methylation biomarker", "predictive marker", "prognostic marker" has been made. This review aims to highlight the most relevant clinical and experimental studies investigating markers for metastasized transitional carcinoma of the urothelium treated by cisplatin based regimens.

Selective organ preservation for the treatment of muscle-invasive transitional cell carcinoma of the bladder: a review of current and future perspectives

Radical treatment remains underutilized for those with muscle-invasive bladder cancer. Radical radiotherapy, in particular, continues to be perceived by many as reserved only for patients unfit for cystectomy. However, with concurrent use of radiosensitizers, radiotherapy can achieve excellent local control and survival comparable to modern surgical series, thus presenting a real alternative to surgery. The possibility of further enhancing patient outcome is likely to come from both advances in radiotherapy treatment delivery and appropriate candidate selection. Growing evidence from selective bladder preservation trials demonstrate long term survival with functional organ preservation. In the era of personalized medicine, we review the evidence supporting an individualized treatment approach, in particular case selection for radical radiotherapy.

Molecular determinants of response to cisplatin-based neoadjuvant chemotherapy

PURPOSE OF REVIEW

Neoadjuvant chemotherapy followed by cystectomy improves survival compared with surgery alone. To prevent overtreatment is of outmost importance to define molecular predictors of response for patient selection. We present the currently available data outlining a variety of potential markers to aid for a personalized decision-making process.

RECENT FINDINGS

Apart from p53, other markers of cell cycle regulation and apoptosis such as p21WAF1/CIP1 (p21) gene, Bcl-2, mouse double minute-2 and pRB have also been related to survival. The clinical relevance of epidermal growth factor receptor and HER2 expression has also been investigated with no success. Regarding Ki67, overexpressing tumors may potentially benefit from neoadjuvant therapy and conversely overexpression of vascular endothelial growth factor and bFGF have been linked to resistance to cisplatin-induced apoptosis. The role of multidrug resistance gene 1 and excision repair cross-complementing rodent repair deficiency complementation group 1 supports that enhanced DNA repair in the tumor decreases the benefit of platinum-based treatment. A 20-gene expression model has shown to predict lymph node involvement, helping on decision-making. A gene expression profiling has been proposed as predictive for response to neoadjuvant chemotherapy.

SUMMARY

Predictive markers will eventually aid in the selection of patients that most likely benefit from preoperative treatment. In the coming years, a panel of markers will become available to achieve the predicted goal.

Molecular mechanisms of cisplatin resistance in bladder cancer

Metastatic disease is the most common mechanism of death in patients with advanced bladder cancer. As for most solid tumors, chemotherapy remains the only realistic option for palliating or curing metastatic disease. However, bladder cancer is characterized by chemoresistance. Only modest response rates are obtained using multiagent regimens including cisplatin. These low response rates and the toxicity of these regimens limit their use to patients at highest risk. Here, we review the molecular mechanisms of cisplatin resistance. These include methods to reduce cisplatin bioavailability within a cell, and defects in the machinery that produces cell death following cisplatin-induced DNA damage. While overcoming these mechanisms is a potential therapeutic approach that can increase response rates, in the short term this knowledge could be used to predict response in individual tumors.

Low ERCC1 expression is associated with prolonged survival in patients with bladder cancer receiving platinum-based neoadjuvant chemotherapy

PURPOSE

Excision repair cross-complementation group 1 enzyme (ERCC1) plays a key role in the removal of platinum induced DNA adducts and cisplatin resistance. Prognostic role of ERCC1 expression in the neoadjuvant setting in bladder cancer has not been reported before. We evaluated the prognostic role of ERCC1 expression in bladder cancer receiving platinum-based neoadjuvant chemotherapy.

MATERIALS AND METHODS

Thirty-eight patients with muscle invasive bladder cancer who received neoadjuvant platinum-based chemotherapy were included. Clinical and histopathologic parameters along with immunohistochemical ERCC1 staining were examined and correlated with response rates and survival.

RESULTS

Pathologic complete response rates were similar between patients with low and high ERCC1 expression. Median disease-free survival (DFS) was 9.3 vs. 20.5 months (P = 0.186) and median overall survival (OS) was 9.3 vs. 26.7 months (P = 0.058) in patients with high ERCC1 expression compared with those with low expression, respectively. In multivariate Cox regression analysis: pathological complete response (pCR) after chemotherapy (hazard ratio (HR) 0.1, 95% CI 0.012-0.842, P = 0.034) and high ERCC1 expression (HR 3.7, 95% CI 1.2-11.2, P = 0.019) were significantly associated with DFS. Patient age (>60 vs. ≤ 60 years) (HR 3.4, 95% CI 1.2-9.4, P = 0.018), the presence of pCR (HR 0.11, 95% CI 0.014-0.981, P = 0.048) and high ERCC expression (HR 6.1, 95 CI 1.9-19.9, P = 0.002) were significantly associated with OS.

CONCLUSIONS

Our results showed that high ERCC1 expression was independently associated with shorter disease-free and overall survival in patients with bladder cancer who received neoadjuvant platinum-based chemotherapy. ERCC1 may represent a potential predictive marker for platinum-based treatment in bladder cancer.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

Current therapeutic strategies for invasive and metastatic bladder cancer

BACKGROUND

Bladder cancer is one of the most common cancers in Europe, the United States, and Northern African countries. Muscle-invasive bladder cancer is an aggressive epithelial tumor, with a high rate of early systemic dissemination. Superficial, noninvasive bladder cancer can most often be cured; a good proportion of invasive cases can also be cured by a combined modality approach of surgery, chemotherapy, and radiation. Recurrences are common and mostly manifest as metastatic disease. Those with distant metastatic disease can sometime achieve partial or complete remission with combination chemotherapy.

RECENT DEVELOPMENTS

Better understanding of the biology of the disease has led to the incorporation of molecular and genetic features along with factors such as tumor grade, lympho-vascular invasion, and aberrant histology, thereby allowing identification of 'favorable' and 'unfavorable' cancers which helps a more accurate informed and objective selection of patients who would benefit from neoadjuvant and adjuvant chemotherapy. Gene expression profiling has been used to find molecular signature patterns that can potentially be predictive of drug sensitivity and metastasis. Understanding the molecular pathways of invasive bladder cancer has led to clinical investigation of several targeted therapeutics such as anti-angiogenics, mTOR inhibitors, and anti-EGFR agents.

CONCLUSION

With improvements in the understanding of the biology of bladder cancer, clinical trials studying novel and targeted agents alone or in combination with chemotherapy have increased the armamentarium for the treatment of bladder cancer. Although the novel biomarkers and gene expression profiles have been shown to provide important predictive and prognostic information and are anticipated to be incorporated in clinical decision-making, their exact utility and relevance calls for a larger prospective validation.

Molecular pathogenesis and diagnostics of bladder cancer

Despite elaborate characterization of the risk factors, bladder cancer is still a major epidemiological problem whose incidence continues to rise each year. Urothelial carcinoma is now recognized as a disease of alterations in several cellular processes. The more prevalent, less aggressive, recurrent, noninvasive tumors are characterized by constitutive activation of the Ras-MAPK pathway. The less common but more aggressive invasive tumors, which have a higher mortality rate, are characterized by alterations in the p53 and retinoblastoma pathways. Several diagnostic tests have attempted to identify these molecular alterations in tumor cells exfoliated in the urine, whereas prognostic tests have tried to identify aberrations so as to predict tumor behavior and identify therapeutic targets. The future of bladder cancer patient management will rely on the use of molecular tests to reliably diagnose the presence of disease, predict individual tumor behavior, and suggest potential targeted therapeutics.

Molecular targeting in the treatment of either advanced or metastatic bladder cancer or both according to the signalling pathways

PURPOSE OF REVIEW

An estimated 300,000 new cases of bladder cancer worldwide are diagnosed annually. Although new cytotoxic chemotherapeutic agents for either advanced or metastatic bladder cancer or both are used, no improvement in survival has been observed. Indeed, the 5-year survival rate of metastatic bladder cancer is very low (6%). The target-directed approach is an attractive challenge for treating specific genetic alterations involved in progression and metastasis development. This article aims to describe the new targeted therapies available to cure advanced cancer or metastatic bladder cancer or both according to the signalling pathways potentially involved.

RECENT FINDINGS

The rapidly expanding understanding of the pathogenesis of bladder cancer at the molecular level has led to the identification of signalling pathways involved in this disease and provided molecular targets for new biological agents directed against tumorigenesis and progression. The recent results of clinical trials have not only highlighted the need to select patients who could benefit from such a therapy but also the fact that oncology has completely entered into a new era.

SUMMARY

Toxic chemotherapeutic agents are slowly being supplemented by a new generation of drugs that recognize specific targets in or on cancer cells. Recent technological advances in pharmacogenomics and proteomics have led to an improvement in identifying biomarkers predictive of response and thereby to identify patients who would be more likely to respond to such a therapy. There is a real hope to improve both the efficiency and the tolerability of bladder cancer treatment.

Bcl-XL and Bcl-2 expression in bilharzial squamous cell carcinoma of the urinary bladder: which protein is prognostic?

OBJECTIVES

Bcl-2 and Bcl-XL are the most important antiapoptotic members of the Bcl-2 family frequently overexpressed in bladder cancer. Overexpression of Bcl-XL bilharzial-related bladder cancer was associated with tumor progression. However, the negative prognostic value of Bcl-2 expression is still questionable. This work studied the expression of Bcl-XL and Bcl-2 immunohistochemically in bilharzial-related squamous cell carcinoma of the urinary bladder and determined their prognostic value in relation to recurrence after radical cystectomy.

METHODS

A total of 72 patients with muscle-invasive bilharzial squamous cell carcinoma of the urinary bladder underwent radical cystectomy at our institution. The specimens were examined immunohistochemically for Bcl-XL and Bcl-2 expression. The patients were followed up for 3 years or until recurrence. The expression of Bcl-XL and Bcl-2 were related to the other prognostic indicators and patient survival.

RESULTS

The expressions of both Bcl-2 and Bcl-XL were significantly different according to the grade of malignancy. Bcl-XL expression was significantly related to tumor recurrence, but Bcl-2 expression was not.

CONCLUSIONS

To our knowledge, the present study is the first report of a negative prognostic value for Bcl-XL in bilharzial squamous cell carcinoma of the urinary bladder. However, this is another negative report on the prognostic value of bcl-2 in bilharzial bladder tumors.

Molecular markers for bladder cancer: the road to a multimarker approach

Bladder cancer is the seventh most common malignancy worldwide, with almost 14,000 patients dying from this disease in the USA alone. Because of the need for long-term and frequent follow-up, as well as the paucity of sensitive and specific noninvasive tests, bladder cancer management has the highest cost per patient among all cancer types. Several molecular markers, especially members of the cell cycle regulation and apoptosis pathways, have been investigated. However, no individual marker has been prognostically powerful enough to change clinical management. The combined analysis of a panel of markers spanning different pathways is the most promising approach. We give an overview of the most important molecular markers functioning in crucial pathways and focus on their role in multimarker analysis.

Trimodality Treatment and Selective Organ Preservation for Bladder Cancer

Standard treatment for muscle-invasive bladder cancer is cystectomy. Trimodality treatment, including transurethral resection of the bladder tumor (TURBT), radiation therapy and chemotherapy, has been shown to produce survival rates comparable to those of cystectomy. With these programs, cystectomy has been reserved for patients with incomplete response or local relapse. During the past 15 years, organ preservation by trimodality treatment has been investigated in prospective series from single centers and cooperative groups, with more than 1,000 patients included. Five-year overall survival rates in the range of 50% to 60% have been reported, and approximately three quarters of the surviving patients maintained their bladder. Clinical criteria helpful in determining ideal patients for bladder preservation include early tumor stage (including high-risk T1 disease), a visibly complete TURBT, and absence of ureteral obstruction. Close coordination among all disciplines is required to achieve optimal results. Future investigations will focus on (1) optimizing radiation techniques and incorporating more effective systemic chemotherapy, and (2) the proper selection of patients based on molecular makers.

Systemic chemotherapy in locally advanced and/or metastatic bladder cancer

Transitional cell carcinoma of the bladder is a common malignancy. Advanced urothelial cancer is a chemosenstive neoplasm. Whereas the MVAC (methotrexate, vinblastine, doxorubicin, and cisplatin) regimen was long-considered the standard of care for patients with advanced disease, the evaluation of newer agents with retained activity and improved tolerability has been the focus of much investigation over the past decade. Combinations such as cisplatin-gemcitabine (GC) and intensified, G-CSF supported MVAC have shown more favourable toxicity profile and equal or even improved efficacy. Specific groups of patients (elderly, patients with renal dysfunction or poor performance status or co-morbidities) who cannot tolerate cisplatin-based therapy, should receive carboplatin, gemcitabine or taxane-based treatment. Continuing improvements in our understanding of the molecular phenotype of individual patient tumors may lead to the appropriate therapies that target molecular aberrations unique to this malignancy. This review will summarize recent developments in the management of locally advanced (T4b, N 2-3) and/or metastatic (M1) bladder cancer.

Molecular biology of bladder cancer: prognostic and clinical implications

The role of various molecular determinants involved in the genesis, progression, and outcome of bladder cancer has been the focus of investigations for the past 2 decades. Increasingly, the analysis of the interplay between these molecular factors is taking center stage. We review herein the studies examining the effects of deregulation of the various molecules implicated in the cell cycle, apoptosis, and angiogenesis pathways and analyze the central role of p53 in regulating these pathways. Technological advancements enable detection and quantification of gene transcripts and protein products, helping us move toward achieving the goal of establishing diagnostic, prognostic, and therapeutic marker panels. Recent studies have therefore focused on multiple-marker analyses to generate informative panels that can have greater clinical value for bladder cancer management. The use of molecular marker panels can provide a more objective alternative to clinical parameters for diagnosis and treatment decisions. Clinical trials aimed at treating urothelial carcinoma based on a patient's molecular profile can be predicted to empower clinicians to personalize patient management through increased therapeutic efficacy.

Neoadjuvant chemotherapy in invasive bladder cancer

The role of neoadjuvant chemotherapy in muscle-invasive bladder cancer has been clarified by recent randomized studies and meta-analyses, which all showed that cisplatin-based, combination chemotherapy offers a significant survival advantage. Preoperative chemotherapy results in downstaging in a significant percentage of patients, which is an independent factor of favorable prognosis. Nevertheless, the optimal sequence of perioperative chemotherapy remains undefined. The authors examine the results of large Phase II and randomized studies as well as the role of neoadjuvant chemotherapy in the context of bladder preservation strategies. Finally, issues of improving therapeutic efficacy and directing clinical research are discussed.

Bladder carcinoma: understanding advanced and metastatic disease with potential molecular therapeutic targets

This article is an expert review of bladder cancer genetics focusing on genetic changes and their significance in the pathogenesis and progression of bladder transitional cell carcinoma, in particular, muscle-invasive disease. Alongside the relevant genetic markers and their products, new therapeutic targets and agents that are being developed are presented.

Chemotherapy for Metastatic Bladder Cancer

This paper reviews the current status of systemic chemotherapy in the management of advanced and metastatic urothelial cancer. The activity of a number of single agents and combination drug regimens is discussed, and the small number of randomised-controlled studies available is also considered. Prognostic factors for response and survival, particularly long-term survival after systemic chemotherapy, are also reviewed. Special consideration is given to the role of systemic chemotherapy as a precursor to surgery (or radiotherapy) in locally advanced disease that is initially considered incurable. Therapeutic options for patients unable to tolerate cisplatin owing to renal impairment or other comorbidities are explored. Future directions are explored, including the role of molecular phenotyping in providing prognostic information, indicators of the likely success of conventional therapeutic measures and the development of specific targeted therapies.

Neoadjuvant Chemotherapy in Transitional-cell Carcinoma of the Bladder

Neoadjuvant chemotherapy in transitional-cell carcinoma of the bladder (TCC) improves survival. This is one of the most important developments in the management of muscle-invasive bladder cancer in recent times. There is an improved absolute 5-year survival of at least 5% for T2-T4 disease. To achieve this benefit, a cisplatin-containing combination is required. There is no difference in survival whether radical radiotherapy or radical cystectomy is given as subsequent definitive treatment.

Systemic chemotherapy for patients with bladder cancer – current controversies and future directions

Many localised, superficial bladder cancers can be effectively controlled. However, disease which has spread to nodes outside the pelvis or to distant organs is generally incurable and systemic therapies, rather than surgery, are appropriate. Combination chemotherapy based around established cytotoxic drugs such as cisplatin has proven benefit in palliating symptoms and prolonging survival in responsive patients with advanced disease. Combination chemotherapies which include newer cytotoxic drugs such as gemcitabine provide the potential for equivalent efficacy with less toxicity than established regimens. Between the extremes of superficial and advanced disease, muscle-invasive bladder cancers have traditionally been treated, with curative intent, by radical surgery or radiotherapy. However, newly published data suggest, for the first time, genuine survival benefits from peri-operative chemotherapy. This article reviews the evidence for cisplatin-based chemotherapy in advanced disease, assesses the potential benefits of newer cytotoxic drugs, discusses the latest evidence pertaining to peri-operative chemotherapy in muscle-invasive disease, and looks forward to potential new biological agents in the systemic therapy of bladder cancer.

The systemic treatment of advanced and metastatic bladder cancer

Bladder cancer is the second most common genitourinary tumour and is a significant cause of morbidity and mortality. Trials of neoadjuvant and adjuvant chemotherapy have failed to show a survival advantage, although these studies generally had suboptimum design and an insufficient number of patients. Despite the introduction of newer agents, the median survival for metastatic disease is about 1 year; however, improvements in quality of life have been achieved. Platinum drugs should be included in studies of combination chemotherapy regimens wherever possible. There have been various studies exploring the role of taxanes, gemcitabine, ifosfamide, and platinum in double and triple combinations in different schedules to maximise dose intensity and improve effectiveness but large phase III trials are needed. The current tumour, node, and metastasis staging system is insufficient to predict outcome in patients with bladder cancer irrespective of the treatment they received. Evaluation of molecular prognostic markers should be incorporated into phase II and III trials to define their roles in clinical outcome. Future studies should stratify patients according to the number of risk factors they have to avoid imbalance in treatment groups and patients should be carefully selected.

Proapoptotic genes BAX and CD40L are predictors of survival in transitional cell carcinoma of the bladder

The purpose of the study was to investigate the effects of expression of a range of genes involved in apoptosis on outcome in bladder cancer. Immunohistochemistry was used to examine expression of BCL2, BAX, P53, CD40 and CD40L in archival tissues of patients included in various treatment trials for transitional cell carcinoma (TCC) of the bladder. Data were collected on 94 patients who first presented with either invasive or superficial bladder cancer. Median follow-up for alive patients was 83 months (m) (range 12-195 m). Median survival was 80 m (95% CI=56-128 m). Median survivals for the various markers were as follows: BAX-positive patients 110 m vs BAX-negative patients 18 m (P=0.0002); CD40L-positive patients 95 m vs CD40L-negative patients 45 m (P=0.04); BCL2-positive patients 44 m and BCL2-negative patients 74 m, (P=0.64); CD40-positive patients 110 m and CD40 negative patients 45 m (P=0.12); and P53 positive patients 80 m and P53 negative patients 45 m (P=0.58). In conclusion, it was seen that overexpressions of BAX and CD40L are prognostic of better survival in TCC of the bladder. Our results also raise the possibility of the future development of CD40- and CD40 ligand-based immunotherapy for bladder cancer. This study links proapoptotic and antiapoptotic markers to overall survival.

Localized and locally advanced bladder cancer

Localized and locally advanced bladder cancer represents a heterogeneous spectrum of diseases with different biologic and clinical behavior. It varies with respect to invasive potential, propensity for metastases, and sensitivity to chemotherapy. Although several significant surgical advances have been made over the past 20 years in the treatment of muscle-invasive bladder cancer, resulting in decreases in perioperative morbidity and mortality and improvement of quality of life in patients with continent urinary diversions, the natural history of the disease has remained unaltered. Advances in chemotherapy for metastatic disease have prompted trials of systemic therapy in patients with early stage, high-risk disease administered before or after local therapy consisting of cystectomy or radiotherapy. The data available from nonrandomized and randomized trials have not definitively established the exact role of neoadjuvant chemotherapy and its impact on survival. Even if neoadjuvant chemotherapy does not improve survival, preliminary data suggest that bladder preservation may be possible in selected patients and that such combined therapy will hopefully lead to better patient management. The trials of postoperative chemotherapy provide insufficient evidence to support the routine use of adjuvant chemotherapy in clinical practice as a result of small sample size, confusing analyses, and the reporting of questionable conclusions. New large-scale, multicenter trials are imperative to provide convincing results. A better understanding of the microbiology of bladder cancer will influence the search for new therapeutic modalities. Molecular-targeted small-molecule therapy and monoclonal antibodies have begun to dominate contemporary studies.

New chemotherapy combinations for advanced bladder cancer

Transitional cell carcinoma of the urothelium is considered a chemosensitive malignancy. Until recently, the methotrexate, vinblastine, doxorubicin and cisplatin combination has been considered the standard for treating this disease. The development of new chemotherapeutic agents such as gemcitabine and the taxanes has opened up promising new perspectives in the treatment of this disease. However, the preliminary phase II data must be confirmed in adequately conducted phase III trials.