Recurrence and progression in low grade papillary urothelial tumors

Low-grade Urothelial Carcinoma Recurs at a Tempo that Naturally Accelerates Over Time

OBJECTIVE

To investigate the cadence of recurrence in patients with low grade intermediate-risk non-muscle invasive bladder cancer (LG IR-NMIBC) based on clinical determinants. We aim to describe patterns in rates of recurrence to better inform surveillance regimens for this chronic, burdensome, and costly disease.

METHODS

Using baseline and follow-up data from participants in the West Midlands' (United Kingdom, UK) Bladder Cancer Prognosis Programme (BCPP), we assessed overall recurrence rate and recurrence-free intervals throughout the follow-up period for IR-NMIBC participants. Recurrence-free intervals were calculated using the Kaplan-Meier method.

RESULTS

We identified 379 patients with G1/G2 pTa tumors classified as intermediate risk. Median age was 70 and 284/379 (75%) were male. The median follow-up time was 4.2 years (95% CI: 3.9-4.8). After 5 years of follow-up, 53% of patients had at least one recurrence. One-year recurrence-free survival (RFS) was 75% and 4-year RFS was 50%. The median time to or between 1st, 2nd, 3rd, 4th, and 5th sequential recurrences was 49, 19, 12, 14, and 10 months, respectively.

CONCLUSION

Over half of patients with IR-NMIBC are destined to recur. Our data suggest that a subset of patients experience acceleration of recurrence over time and that this acceleration may serve as a potential kinetic biomarker for these individuals that could inform surveillance intervals and future treatment strategies.

Recent Advances in the Classification of Bladder Cancer - Updates from the 5th Edition of the World Health Organization Classification of the Urinary and Male Genital Tumors

BACKGROUND

The World Health Organization Classification (WHO) of Urinary and Male Genital Tumors has recently been updated to its 5th edition. The new edition presents a comprehensive approach to the classification of urinary and male genital tumors with an incorporation of morphologic, clinical, and genomic data.

OBJECTIVE

This review aims to update the new classification of bladder cancer in the 5th edition and to highlight important changes in nomenclatures, diagnostic criteria, and molecular characterization, as compared to the 4th edition.

METHODS

The pathologic classification of bladder cancer in the 5th edition of WHO Classification of Urinary and Male Genital Tumours was compared to that in the 4th edition. PubMed was searched using key words, including bladder cancer, WHO 1973, WHO 1998, WHO 2004, WHO 2016, histology, pathology, genomics, and molecular classification in the time frame from 1973 to August of 2022. Other relevant papers were also consulted, resulting in the selection of 81 papers as references.

RESULTS

The binary grading of papillary urothelial carcinoma (UC) is practical, but it may be oversimplified and contribute to "grade migration" in recent years. An arbitrary cutoff (5%) has been proposed for bladder cancers with mixed grades. The diagnosis of papillary urothelial neoplasm with low malignant potential has been dramatically reduced in recent years because of overlapping morphology and treatment with low-grade papillary UC. An inverted growth pattern should be distinguished from true (or destructive) stromal invasion in papillary UC. Several methods have been proposed for pT1 tumor substaging, but it is often challenging to substage pT1 tumors in small biopsy specimens. Bladder UC shows a high tendency for divergent differentiation, leading to several distinct histologic subtypes associated with an aggressive clinical behavior. Molecular classification based on the genomic analysis may be a useful tool in the stratification of patients for optimal treatment.

CONCLUSIONS

The 5th edition of WHO Classification of Urinary and Male Genital Tumours has made several significant changes in the classification of bladder cancer. It is important to be aware of these changes and to incorporate them into routine clinical practice.

The natural history of low-risk non-muscle-invasive bladder cancer: a collaborative multi-centre study

BACKGROUND

International guidelines vary in terms of their definition and recommendation for management of low-risk non-muscle-invasive bladder cancer (LRNMIBC). The ideal management for this large subset of bladder cancer patient remains unclear.

OBJECTIVE

To evaluate long-term outcomes of patients with LRNMIBC. As a secondary objective, to assess for intergroup heterogeneity in disease-specific outcomes between G1 and G2LG diseases.

METHODS

A multi-centre, retrospective study of patients who met the 2015 NICE definition of LRNMIBC. Timeline of diagnosis ranged from 01/01/2012 to 30/06/2016.

RESULTS

A total 390 patients had available follow-up data (G1: 142, G2LG: 249). Over a median follow-up time of 36 months (IQR 25-50), 29.2% of the patients developed a recurrence. G2LG patients were statistically more likely to develop a recurrence (G1: 26.8%, G2LG: 33.7%, p < 0.05). 51.8% of recurrences occurred after 1 year of surveillance. Progression to high-grade disease occurred in 1.8% (n = 7, G1: 3, G2LG: 4) and a further 1.0% (n = 4, G1:3, G2LG: 1) of patients developed muscle-invasive bladder cancer (MIBC).

CONCLUSION

The majority of recurrences occurred after 1 year of surveillance. The risk of disease progression was low; however, this was observed in a cohort of patients with regular cystoscopic follow-up. The risk may be higher if patients were pre-maturely discharged. If a 5-year surveillance programme were to be followed, 96.5% of recurrences would be captured. Lastly, there appears to be intergroup heterogeneity within LRNMIBC with G2LG patients having a statistically higher risk of recurrence compared to G1.

News in the classification of WHO 2022 bladder tumors

The fifth-edition of World Health Organization (WHO) Classification of Tumors series for urinary and male genital tract tumors has been published, six years later the fourth-edition. In these years, new treatment approaches have been implemented and new molecular data on urological cancers are known.

Morphology remains the groundwork for taxonomy of the urinary tract tumors. However, a molecular approach to classification of urothelial carcinomas and the management of selected neoplasms with new therapeutic modalities such as immunotherapy are emerging. More data are needed for the application of these advances in routine pathology practice and patient management.

The 2022 World Health Organization (WHO) Classification of Tumors of the Urinary System and Male Genital Organs represents an update in classification on urinary tract tumors. It also offers new insights with regards to the grading of heterogeneous non-invasive urothelial neoplasms, the definition of inverted neoplasms, the grading of invasive urothelial carcinomas, the diversity of morphological appearance of urothelial carcinomas, the definition of precursor lesions and the lineage of differentiation of the tumors.

Bladder cancer recurrence in papillary urothelial neoplasm of low malignant potential (PUNLMP) compared to G1 WHO 1999: a population-based study

OBJECTIVE

Papillary urothelial neoplasm of low malignant potential (PUNLMP) and stage TaG1 non-muscle invasive bladder cancer (NMIBC) represent separate categories in current WHO 1999 grade definitions. Similarly, PUNLMP and Ta low-grade are separate entities in the WHO 2004/2016 grading system. However, this classification is currently questioned by reports showing a similar risk of recurrence and progression for both categories.

PATIENTS AND METHODS

In this population-based study, risk estimates were evaluated in patients diagnosed with PUNLMP (n = 135) or stage TaG1 (n = 2176) NMIBC 2004-2008 with 5-year follow-up registration in the nation-wide Bladder Cancer Data Base Sweden (BladderBaSe). The risk of recurrence was assessed using multivariable Cox regression with adjustment for multiple confounders (age, gender, marital status, comorbidity, educational level, and health care region).

RESULTS

At five years, 28/135 (21%) patients with PUNLMP and 922/2176 (42%) with TaG1 had local recurrence. The corresponding progression rates were 0.7% (1/135) and 4.0% (86/2176), respectively. A higher relative risk of recurrence was detected in patients with TaG1 tumours compared to PUNLMP (Hazard Ratio 1.6, 95% CI 1.2-2.0) at 5-year follow-up, while progression events were too few to compare.

CONCLUSIONS

The difference in risk of recurrence between primary stage TaG1 and PUNLMP stands in contrast to the recently adapted notion that treatment and follow-up strategies can be merged into one low-risk group of NMIBC.

Novel transurethral resection technologies and training modalities in the management of nonmuscle invasive bladder cancer: a comprehensive review

PURPOSE OF REVIEW

Conventional transurethral resection (TURBT) with tumor fragmentation is the primary step in the surgical treatment of nonmuscle invasive bladder cancer. Recently, new surgical techniques and training modalities have emerged with the aim to overcome short-comings of TURBT and improve oncologic outcomes. In this review, we provide a comprehensive update of recent techniques/techniques that aim to improve upon conventional TURBT and beyond.

RECENT FINDINGS

A systemic approach during conventional TURBT that features the use of a surgical checklist has been shown to improve recurrence-free survival. Several simulators have been developed and validated to provide additional training opportunities. However, transfer of improved simulator performance into real world surgery still requires validation. While there is no convincing data that demonstrate superior outcomes with bipolar TURBT, en-bloc resection already promises to offer lower rates of complications as well as potentially lower recurrence probabilities in select patients.

SUMMARY

TURBT remains the quintessential procedure for the diagnosis and treatment of bladder cancer. Urologists need to be aware of the importance and challenges of this procedure. Aside of embracing new resection techniques and a conceptual-systematic approach, training opportunities should be expanded upon to improve patient outcomes.

The Genitourinary Pathology Society Update on Classification and Grading of Flat and Papillary Urothelial Neoplasia With New Reporting Recommendations and Approach to Lesions With Mixed and Early Patterns of Neoplasia

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder neoplasia with a focus on issues relevant to the practicing surgical pathologist for the understanding and effective reporting of bladder cancer, emphasizing particularly on the newly accumulated evidence post-2016 World Health Organization (WHO) classification. The work is presented in 2 manuscripts. Here, in the first, we revisit the nomenclature and classification system used for grading flat and papillary urothelial lesions centering on clinical relevance, and on dilemmas related to application in routine reporting. As patients of noninvasive bladder cancer frequently undergo cystoscopy and biopsy in their typically prolonged clinical course and for surveillance of disease, we discuss morphologies presented in these scenarios which may not have readily applicable diagnostic terms in the WHO classification. The topic of inverted patterns in urothelial neoplasia, particularly when prominent or exclusive, and beyond inverted papilloma has not been addressed formally in the WHO classification. Herein we provide a through review and suggest guidelines for when and how to report such lesions. In promulgating these GUPS recommendations, we aim to provide clarity on the clinical application of these not so uncommon diagnostically challenging situations encountered in routine practice, while also importantly advocating consistent terminology which would inform future work.

Combining two grading systems: the clinical validity and inter-observer variability of the 1973 and 2004 WHO bladder cancer classification systems assessed in a UK cohort with 15 years of prospective follow-up

Purpose

Paucity of reliable long-term data on the prognostic implications of the 2004 WHO bladder cancer classification system necessitates utilisation of both this and the 1973 grading systems. This study evaluated, in noninvasive (pTa) bladder tumours, the prognostic value of the 2004 system independently and in combination with the 1973 system while establishing concordance between tertiary centre uropathologists.

Methods

We used a cohort of non-muscle invasive bladder cancer (NMIBC) patients diagnosed between 1991 and 93 where tumour features were gathered prospectively with detailed cystoscopic follow-up data recorded over 15 years. Initial grading was by one senior expert uropathologist (UP1) using the 1973 WHO classification alone. Subsequently, two other expert uropathologists (UP2 and UP3), blinded to the previous grading, re-evaluated the pathology slides and graded the tumours using both the 1973 and 2004 systems. Association between grade and recurrence/progression was analysed and the Cohen Kappa test assessed concordance between pathologists.

Results

Of 370 new NMIBC, 229 were staged noninvasive (pTa). Recurrence rates were 46.2% and 50.0% for LGPUC (low-grade papillary urothelial carcinoma) and HGPUC (high-grade papillary urothelial carcinoma), respectively, while progression was seen in 3.9% and 10.0% of LGPUC and HGPUC, respectively. Concordance between uropathologists UP2 and UP3 for the 2004 and 1973 systems was good (Kappa = 0.69) and fair (Kappa = 0.25), respectively.

Conclusions

With good inter-observer concordance, the 2004 WHO classification system of noninvasive bladder tumours appears to accurately predict recurrence and progression risks. The combination of both grading systems to low-grade tumours allows further refinement of the natural history.

Predicting outcomes in non-muscle invasive (Ta/T1) bladder cancer: the role of molecular grade based on luminal/basal phenotype

Bladder cancer tumors can be divided into two molecular subtypes referred to as luminal or basal. Each subtype may react differently to current chemotherapy or immunotherapy. Likewise, the technology required for comprehensive molecular analysis is expensive and not yet applicable for routine clinical diagnostics. Therefore, it has been suggested that the immunohistochemical expressions of only two markers, luminal (CK20+, CK5/6-) and basal (CK5/6+, CK20-), is sufficient to identify the molecular subtypes of bladder cancer. This would represent a molecular grade that could be used in daily practice. Molecular classification is done using immunohistochemistry to assess luminal-basal phenotype based on tissular expression of CK20 and CK5/6 as surrogate for luminal or basal subtypes, respectively. A series of 147 non-muscle-invasive bladder carcinoma cases was selected, and the tumors were divided into four subgroups based on the presence of CK20 and/or CK5/6, that is, null (CK20-, CK5/6-), mixed (CK20+, CK5/6+), basal (CK20-, CK5/6+), and luminal (CK20+, CK5/6-) categories. Survival analysis was estimated using the Kaplan-Meier method and the log-rank test. Hazard ratios were calculated by Cox multivariate analysis. The molecular grade included cases with null (n = 89), mixed (n = 6), basal (n = 20), and luminal (n = 32) phenotypes with differences in recurrence-free, progression-free and cancer-specific survival associated with molecular-grade categories in patients with low- or high-grade Ta, or high-grade T1 tumors. The multivariate analysis identified the luminal phenotype as a predictor of more aggressive neoplasms. Our findings provide a rationale to investigate luminal and basal subtypes of bladder cancer using two gene expression signatures as surrogate markers and show that non-muscle-invasive bladder carcinoma can be stratified into biologically and clinically different subgroups by using an immunohistochemical classifier.

Papillary Urothelial Neoplasm of Low Malignant Potential (PUNLMP) After Initial TUR-BT: Comparative Analyses with Noninvasive Low-Grade Papillary Urothelial Carcinoma (LGPUC)

Purpose: To verify if the distinction between papillary urothelial neoplasm of low malignant potential (PUNLMP) and noninvasive low-grade papillary urothelial carcinoma (LGPUC) reflects a different biologic activity. Materials and Methods: We reviewed and analyzed the clinical data from 678 patients who had a diagnosis of PUNLMP (n=53) or noninvasive LGPUC (n=625) after initial TUR-BT for bladder neoplasm between 2000 and 2012. Results: The noninvasive LGPUC group showed a higher frequency of recurrence in comparison with the PUNLMP group (46.7% vs. 30.2%, p=0.022). In contrast, there were no significant differences in progression (15.2% vs. 18.9%, p=0.295) between the two groups. Grade progression was reported in 10 patients (LG: n=5; high grade: n=2; carcinoma in situ: n=3) and stage progression was reported in 2 patients (all: T1) in PUNLMP group. The Kaplan-Meier survival analysis showed significantly decreased 5-year recurrence-free survival (RFS) (50.3% vs. 74.6%, log-rank test, p=0.014) in the noninvasive LGPUC group compared to the PUNLMP group. However, there were no significant differences in progression-free survival (PFS) between the two groups. Multivariate analysis revealed that tumor grades according to 2004 WHO/ISUP classification system (PUNLMP vs. LG) were identified as significant predictors of RFS. However, it was not a significant predictor of both PFS and overall survival. Conclusions: PUNLMP had a substantial number of recurrences (30.2%), although RFS was better than noninvasive LGPUC. In addition, PUNLMP had a similar risk of progression compared with noninvasive LGPUC. Consequently, PUNLMP should be treated in a manner similar to noninvasive LGPUC, and long-term clinical follow-up should be recommended for patients with PUNLMP.

Increased Proliferation as Independent Predictor of Disease Recurrence in Initial Stage pTa Urothelial Bladder Cancer

Objectives:

To investigate the predictive impact of the proliferation biomarker Ki-67 on the clinical course of patients with initial stage pTa urothelial carcinoma of the bladder (UCB).

Methods:

We retrospectively analyzed all patients treated by transurethral resection of bladder tumors (TUR-B) for UCB between 1992–2004 in a single-center. Disease recurrence (≥pTa UCB) and absent tumor in histopathology, assessed by TUR-B with a non-malignant result for endoscopic suspect bladder lesion displayed endpoints. Immunohistochemical (IHC) analysis of formalin-fixed and paraffin-embedded tissue blocks was performed with an immunostainer using a primary antibody for Ki-67. Semiquantitative evaluation of Ki-67 was performed by three reviewers. Increased proliferation was defined with a cut-off value of ≥50%. Uni- and multivariable binary regression analyses were applied to address prediction of disease recurrence.

Results:

215 patients (84% male, median age 69 years at first diagnosis) were evaluable and included to the study. 89 patients stayed disease-free (41%), 126 patients showed recurrence (59%). Recurrence rates of patients with Ki-67 expression <10%, 10–24%, 25–49% and ≥50% were 14.8% vs. 30.8% vs. 63.9% and 80.7%, respectively (p < 0.001). In Kaplan-Meier analysis patients with increased proliferation ≥50% showed a statistically significant worse 10-year recurrence-free survival (19% vs. 57%, p < 0.001). Multivariable regression analysis revealed instillation treatment (p = 0.001) and high proliferation of Ki-67 (p < 0.001) to be independent predictors of recurrence in stage pTa UCB.

Conclusions:

High proliferation with Ki-67 expression ≥50% was strongly associated with worse recurrence-free survival in patients with initial stage pTa UCB. Stage pTa UCB patients with increased Ki-67 expression should undergo a strictly follow-up regime comparable to stage pT1 bladder carcinoma, while at least patients with Ki-67 expression <10% might be feasible for more liberate follow-up regime after evaluation of our data in randomized, prospective and multicenter studies.

Spectrum of genetic mutations in de novo PUNLMP of the urinary bladder

Our group and others have previously demonstrated the presence of TERT promoter mutations (TERT-mut) in 60-80% of urothelial carcinomas and some of their histologic variants. Five other genes have been frequently implicated in bladder cancer: FGRF3, TP53, PIK3CA, HRAS, and CDKN2A. In the current study, we sought to determine the prevalence of mutations in TERT and these five other genes in de novo papillary urothelial neoplasms of low malignant potential (PUNLMP) of the urinary bladder. A retrospective search of our archives for PUNLMP was performed and 30 de novo cases were identified and included in the study. We found mutations in TERT (TERT-mut) and FGFR3 (FGFR3-mut) to be the most common alterations in the cohort (63 and 60%, respectively). The majority of the TERT-mut-positive tumors (84%) had a g.1295228C > T alteration with the remaining tumors demonstrating g.1295250C > T. Approximately one fourth of tumors had TP53 mutations. These findings support the potential utility of a uniform genetic mutation panel to detect bladder cancers of various subtypes.

Narrow band imaging-assisted transurethral resection reduces the recurrence risk of non-muscle invasive bladder cancer: A systematic review and meta-analysis

CONTEXT

Compared with white light imaging (WLI) cystoscopy, narrow band imaging (NBI) cystoscopy could increase the visualization and detection of bladder cancer (BC) at the time of transurethral resection (TUR). NBI cystoscopy could increase the detection of BC, but it remains unclear whether narrow band imaging-assisted transurethral resection (NBI-TUR) could reduce the recurrence risk of non-muscle invasive bladder cancer (NMIBC). Several randomized clinical trials (RCTs) have recently tested the efficacy of NBI-TUR for NMIBC.

OBJECTIVE

To perform a systematic review and meta-analysis of RCTs and evaluate the efficacy of NBI-TUR for NMIBC compared with white light imaging-assisted transurethral resection (WLI-TUR). The end point was recurrence risk.

EVIDENCE ACQUISITION

A systematic review of PubMed, Medline, Ovid, Embase, Cochrane and Web of Science was performed in February 2016 and updated in July 2016.

EVIDENCE SYNTHESIS

Overall, six (n = 1084) of 278 trials were included. Three trials performed narrow band imaging-assisted electro-transurethral resection (NBI-ETUR), and two trials performed narrow band imaging-associated bipolar plasma vaporization (NBI-BPV). The last trial performed narrow band imaging-associated holmium laser resection (NBI-HLR). Statistical analysis was performed using Review Manager software (RevMan v.5.3; The Nordic Cochrane Center, Copenhagen, Denmark). The recurrence risk was compared by calculating risk ratios (RRs) with 95% confidence interval (CIs). Risk ratios with 95% CIs were calculated to compare 3-mo, 1-yr, and 2-yr survival rates. NBI-TUR was associated with improvements in the 3-mo recurrence risk (RR: 0.39; 95% CI, 0.26-0.60; p < 0.0001), 1-yr recurrence risk (RR: 0.52; 95% CI, 0.40-0.67; p < 0.00001) and 2-yr recurrence risk (RR: 0.60; 95% CI, 0.42-0.85; p = 0.004) compared with WLI-TUR.

CONCLUSIONS

Compared with WLI-TUR, NBI-TUR can reduce the recurrence risk of NMIBC. The results of this review will facilitate the appropriate application of NBI in NMIBC.

Diagnostics techniques in nonmuscle invasive bladder cancer

INTRODUCTION

Nonmuscle invasive bladder cancer (NMIBC) is the most common presentation of bladder cancer and is often treatable with endoscopic resection and intravesical therapies. Cystoscopy and urine cytology are the gold standard in diagnosis and surveillance but are limited by their sensitivity in some situations. We seek to provide an overview of recent additions to the diagnostic armamentarium for urologists treating this disease.

METHODS

Articles were identified through a literature review of articles obtained through PubMed searches including the terms "bladder cancer" and various diagnostic techniques described in the article.

RESULTS

A variety of urinary biomarkers are available to assist the diagnosis and management of patients with NMIBC. Many have improved sensitivity over urine cytology, but less specificity. There are certain situations in which this has proved valuable, but as yet these are not part of the standard guidelines for NMIBC. Fluorescence cystoscopy has level 1 evidence demonstrating increased rates of tumor detection and prolonged recurrence-free survival when utilized for transurethral resection. Other technologies seeking to enhance cystoscopy, such as narrow band imaging, confocal laser endomicroscopy, and optical coherence tomography are still under evaluation.

CONCLUSIONS

A variety of urine biomarker and adjunctive endoscopic technologies have been developed to assist the management of NMIBC. While some, such as fluorescence cystoscopy, have demonstrated a definite benefit in this disease, others are still finding their place in the diagnosis and treatment of this disease. Future studies should shed light on how these can be incorporated to improve outcomes in NMIBC.

Phosphorylated p70S6K in noninvasive low-grade urothelial carcinoma of the bladder: correlation with tumor recurrence

We investigated whether inhibiting phosphorylated p70S6K (p-p70S6K) suppresses the proliferation and growth of noninvasive low-grade urothelial carcinoma (LG-URCa) in vitro and whether p-p70S6K can serve as a predictive biomarker for the recurrence of noninvasive LG-URCa of the bladder in patients. We constructed a tissue microarray (TMA) for 95 LG-URCa and 35 benign urothelium samples and performed immunohistochemical staining for p-p70S6K and p-4E-BP1. A Cox regression model was used to investigate the predictive factors for recurrence of LG-URCa. We investigated the dose-dependent antiproliferative effect of rapamycin, its antiproliferative effect and the growth-inhibition effect of p70S6K siRNA transfection in RT4 and 253J cell lines. The pT1 staged group (P < 0.05; hazard ratio (HR), 2.415) and the high p-p70S6K staining group (P < 0.05; HR, 2.249) were independent factors for predicting recurrence. Rapamycin inhibited RT4 and 253J cell proliferation in a dose-dependent manner (r = −0.850, P < 0.001 in RT4 cells; r = −0.835, P < 0.001 in 253J cells). RT4 and 253J cell proliferation and growth were inhibited by the transfection of p70S6K siRNA and rapamycin, respectively (P < 0.05). Transfection of p70S6K siRNA resulted in inhibitory effects on cell proliferation and growth that were similar to those of rapamycin. Our results suggest that inhibiting p70S6K phosphorylation is important to prevent recurrence and that p70S6K phosphorylation can be used as a molecular biomarker to predict recurrence of certain LG-URCa of the bladder.

Activation of EZH2 and SUZ12 Regulated by E2F1 Predicts the Disease Progression and Aggressive Characteristics of Bladder Cancer

PURPOSE

Previous study identified E2F1 as a key mediator of non-muscle-invasive bladder cancer (NMIBC) progression. The aim of this study was to identify the E2F1-related genes associated with poor prognosis and aggressive characteristics of bladder cancer.

EXPERIMENTAL DESIGN

Microarray analysis was performed to find E2F1-related genes associated with tumor progression and aggressiveness in the gene expression data from 165 primary patients with bladder cancer. The biologic activity of E2F1-related genes in tumor progression and aggressiveness was confirmed with experimental assays using bladder cancer cells and tumor xenograft assay.

RESULTS

The expression of E2F1 was significantly associated with EZH2 and SUZ12. The overexpression of E2F1, EZH2, and SUZ12 enhanced cancer progression including cell colony formation, migration, and invasiveness. Knockdown of these genes reduced motility, blocked invasion, and decreased tumor size in vivo. E2F1 bound the proximal EZH2 and SUZ12 promoter to activate transcription, suggesting that E2F1 and its downstream effectors, EZH2 and SUZ12, could be important mediators for the cancer progression. In addition, we confirmed an association between these genes and aggressive characteristics. Interestingly, the treatment of anticancer drugs to the cells overexpressing E2F1, EZH2, and SUZ12 induced the expression of CD44, KLF4, OCT4, and ABCG2 known as cancer stem cell (CSC)-related genes.

CONCLUSIONS

The link between E2F1, EZH2, and/or SUZ12 revealed that E2f1 directly regulates transcription of the EZH2 and SUZ12 genes. The signature of E2F1-EZH2-SUZ12 shows a predictive value for prognosis in bladder tumors and the E2F1-EZH2-SUZ12-driven transcriptional events may regulate the cancer aggressiveness and chemo-resistance, which may provide opportunity for development of new treatment modalities.

Molecular and clinical support for a four-tiered grading system for bladder cancer based on the WHO 1973 and 2004 classifications

Currently, the use of two classification systems for bladder cancer grade is advocated in clinical guidelines because the WHO2004 classification has not been sufficiently validated with biological markers and follow-up. The slides of 325 primary non-muscle invasive bladder cancers from three hospitals were reviewed by one uro-pathologist in two separate sessions for the WHO1973 (G1, G2 and G3) and 2004 (papillary urothelial neoplasm of low malignant potential (LMP), low-grade (LG) and high-grade (HG)) classifications. FGFR3 status was examined with PCR-SNaPshot analysis. Expression of Ki-67, P53 and P27 was analyzed by immuno-histochemistry. Clinical recurrence and progression were determined. We performed validation and cross-validation of the two systems for grade with molecular markers and clinical outcome. Multivariable analyses were done to predict prognosis and pT1 bladder cancer. Grade review resulted in 88 G1, 149 G2 and 88 G3 lesions (WHO1973) and 79 LMP, 101 LG and 145 HG lesions (WHO2004). Molecular validation of both grading systems showed that FGFR3 mutations were associated with lower grades whereas altered expression (Ki-67, P53 and P27) was found in higher grades. Clinical validation showed that the two classification systems were both significant predictors for progression but not for recurrence. Cross-validation of both WHO systems showed a significant stepwise increase in biological (molecular markers) and clinical (progression) potential along the line: G1-LG-G2-HG-G3. The LMP and G1 categories had a similar clinical and molecular profile. On the basis of molecular biology and multivariable clinical data, our results support a four-tiered grading system using the 1973 and 2004 WHO classifications with one low-grade (LMP/LG/G1) category that includes LMP, two intermediate grade (LG/G2 and HG/G2) categories and one high-grade (HG/G3) category.

P70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression in orthotopic mouse non-muscle invasive bladder tumor model

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 µM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.

Long-term follow-up of TaG1 non-muscle-invasive bladder cancer

OBJECTIVES

To retrospectively assess the long-term outcome of patients initially diagnosed with TaG1 non-muscle-invasive bladder cancer (NMIBC) with no immediate postoperative instillation of intravesical chemotherapy and evaluate the reproducibility of the European Organization for Research and Treatment of Cancer (EORTC) scoring system for predicting bladder cancer outcome.

METHODS AND MATERIALS

A retrospective analysis of 481 consecutive cases of initially diagnosed TaG1 NMIBC according to the 1973 World Health Organization classification between 1995 and 2008 in a single institution was performed. Time to first recurrence, time to progression to T1 or G3 bladder cancer, and time to progression to muscle-invasive bladder cancer were studied. Time to event distributions was estimated by means of cumulative incidence functions to accurately take into account the patients who died (competing risk) before recurrence or progression. The Harrell c statistic calculation was used for our study's data results as well the original data from EORTC to compare the predictive power of a survival model.

RESULTS

The median follow-up was 88 months (interquartile range: 51-135 mo). The 10-year recurrence-free, T1 or G3 NMIBC progression-free, and muscle-invasive bladder cancer progression-free survival rates were 64.2%, 96.6%, and 97%, respectively. In multivariate analysis, tumor size and number of lesions were prognostic variables of the risk of recurrence. In our study and EORTC data sets, the Harrell c values obtained were c = 0.85 (95% CI: [0.75, 0.93]) and c = 0.85 (95% CI: [0.75, 0.93]), respectively.

CONCLUSION

Our study reports a detailed and extensive outcome of TaG1 NMIBC treated by TURB with no immediate postoperative intravesical instillation of chemotherapy. Our results suggest that the EORTC is a useful external validation scoring system for predicting bladder cancer outcome.

Reduced CD151 expression is related to advanced tumour stage in urothelial bladder cancer

AIMS

CD151 belongs to the group of tetraspanins and is aberrantly expressed in different tumours and differential expression has been associated with prognosis. The aim of this study was to clarify the relationship of CD151 expression with tumour phenotype and clinical outcome in bladder cancer.

METHODS

A bladder cancer tissue microarray containing samples from 686 urothelial bladder cancers was analysed by immunohistochemistry.

RESULTS

Membranous CD151 immunostaining was recorded in 409 (66.0%) of 620 analysable cases. High CD151 expression was seen in normal urothelium and in most non-invasive tumours. Low CD151 expression levels were associated with a more unfavourable tumour phenotype. CD151 staining was seen in 71.5% of 284 pTa, 62.1% of 145 pT1 and 60.4% of 187 pT2-4 cancers (p = 0.0033). CD151 staining was detectable in 77.3% of 75 grade 1, 71.1% of 273 grade 2 and 57.7% of 272 grade 3 cancers (p < 0.0001). CD151 expression status was not associated with overall or tumour-specific survival in muscle-invasive cancers (pT2-4), tumour progression in pT1 and recurrences in pTa tumours.

CONCLUSION

On the basis of our data we conclude that loss of CD151 may contribute to bladder cancer progression through attenuation of cell adhesion. In clinically defined subgroups CD151 expression does not provide additional prognostic information.

Novel endoscopic diagnosis for bladder cancer

Advances in endoscopic imaging technology may improve sensitivity for the detection of bladder cancer and provide a more complete understanding of the urothelial landscape, and it also may lead to improved short-term and long-term cancer control. Fluorescence cystoscopy requires intravesical administration of a photosensitizing agent (5-aminolevulinic acid or hexaminolevulinate), and imaging with a blue-light endoscopy system demonstrably improves the detection of papillary and flat bladder lesions compared with conventional white-light cystoscopy. Prospective phase 3 clinical trials have demonstrated improved diagnostic ability, enhanced tumor resection, and a small but significant reduction in recurrence-free survival. Optical coherence tomography delineates subsurface microarchitecture information about bladder lesions in real time and has the ability to discriminate between noninvasive and invasive cancers. Narrow-band imaging may augment white-light cystoscopy by providing increased contrast between normal and abnormal tissue on the basis of neovascularity. Confocal laser endoscopy has been applied to the urinary tract using thinner probes adapted from use in gastrointestinal malignancies and provides exquisite images at microscopic resolution. More technology is on the horizon that may further enhance our ability to detect and accurately stage bladder tumors and distinguish benign from malignant or dysplastic lesions.

Long-term cancer-specific outcomes of TaG1 urothelial carcinoma of the bladder

BACKGROUND

Few studies have investigated the natural history of TaG1 urothelial carcinoma of the bladder (UCB).

OBJECTIVE

To assess the long-term outcomes of patients with TaG1 UCB and the impact of immediate postoperative instillation of chemotherapy (IPIC).

DESIGN, SETTING, AND PARTICIPANTS

A retrospective analysis of 1447 patients with TaG1 UCB treated between 1996 and 2007 at eight centers. Median follow-up was 67.2 mo (interquartile range: 67.9). Patients were stratified into three European Association of Urology (EAU) guidelines risk categories; high-risk patients (n=11) were excluded.

INTERVENTION

Transurethral resection of the bladder with or without IPIC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable Cox regression models addressed factors associated with disease recurrence, disease progression, death of disease, and any-cause death.

RESULTS AND LIMITATIONS

Of the 1436 patients, 601 (41.9%) and 835 (58.1%) were assigned to low- and intermediate-risk categories, respectively. The actuarial estimate of 5-yr recurrence-free survival was 56% (standard error: ± 1). Advancing age (p=0.04), tumor >3 cm (p=0.001), multiple tumors (p<0.001), and recurrent tumors (p<0.001) were independently associated with increased risk of disease recurrence, whereas IPIC was associated with decreased risk (p=0.001). The actuarial estimate of 5-yr progression-free survival was 95% ± 1. Advancing age (p<0.001) and multiple tumors (p=0.01) were independent risk factors for disease progression. Five-year cancer-specific survival was 98% ± 1. Advancing age (p=0.001) and previous recurrence (p=0.04) were associated with increased risk, whereas female gender (p=0.02) was associated with decreased risk of cancer-specific mortality. Compared with low-risk patients, intermediate-risk patients were at significantly higher risk of disease recurrence, disease progression, and cancer-specific mortality (all p<0.01). Limitations include the retrospective design of the study and the lack of a central pathology review.

CONCLUSIONS

TaG1 UCB patients experience heterogeneous risks of disease recurrence. We validated the EAU guidelines risk stratification in TaG1 UCB patients. IPIC was associated with a reduced risk of disease recurrence in patients with low- and intermediate-risk TaG1 UCB.

Photodynamic effect of 5-aminolevulinic acid-loaded nanoparticles on bladder cancer cells: a preliminary investigation

OBJECTIVE

The aim of this study was to assess the photodynamic effect of nanoparticles loaded with a photosensitizing nanomedicine, 5-aminolevulinic acid (5-ALA), on T24 bladder cancer cells in vitro.

MATERIAL AND METHODS

The nanoprecipitation technique was successfully used to prepare the drug-loaded polymeric nanoparticles. The drug loading rate and the drug loading efficiency were determined by ultraviolet spectrophotometry. The size and morphology of nanoparticles were detected using dynamic light scattering (DLS) and transmission electron microscopy. Cytotoxicity to T24 bladder cancer cells was assessed by coincubating 5-ALA-loaded nanoparticles of different concentrations with T24 bladder cancer cells. The cell growth inhibitory rate was measured after irradiation by a 650 nm wavelength diode laser.

RESULTS

The drug loading rate of 5-ALA-loaded nanoparticles was 7% with a loading efficiency of 85%. The T24 cell growth inhibitory rates after incubation with 5.0, 10.0, 25.0 and 50.0 μg/ml 5-ALA-loaded nanoparticles were 73.19%, 79.95%, 83.86% and 89.74%, respectively, which demonstrated significantly higher cytotoxicity than those in the empty nanoparticle groups and 5-ALA free drug groups (p < 0.05).

CONCLUSIONS

5-ALA-loaded nanoparticles were successfully prepared and had a significantly enhanced photodynamic tumoricidal effect on bladder cancer cells in vitro.

Comparison of surveillance strategies for low-risk bladder cancer patients

OBJECTIVE

Low-grade noninvasive disease comprises approximately half of incident bladder cancer cases. These lesions have exceedingly low rates of progression to aggressive, muscle-invasive bladder cancer, and there is salient discordance with regard to management recommendations for these patients between the principal clinical practice guidelines. In this context, we compare the international guidelines with alternative surveillance strategies for low-risk bladder cancer patients.

METHODS

We used a partially observable Markov model based on states that defined patient risk levels associated with recurrence and progression of bladder cancer. The model also included states defining the effects of treatment, death from bladder cancer, and all other-cause mortality. Simulation was done to estimate quality-adjusted life years (QALYs), expected lifelong progression probability, and lifetime number of cystoscopies.

RESULTS

We compared current international guidelines and additional proposed surveillance strategies on the basis of QALYs. We conducted a bicriteria analysis to compare expected lifelong progression rate v. the number of cystoscopies. One-way sensitivity analysis was used to evaluate the influence of model parameters, including a patient's disutility associated with cystoscopy, bladder cancer mortality, and all other-cause mortality.

CONCLUSIONS

Age and comorbidity significantly affect the optimal surveillance strategy. Results suggest that younger patients should be screened more intensively than older patients, and patients having comorbidity should be screened less intensively.

Disease specific mortality in patients with low risk bladder cancer and the impact of cystoscopic surveillance

PURPOSE

We determined the risk of disease specific mortality in patients with primary, low risk, noninvasive (G1pTa) bladder cancer and compared it to disease specific mortality in age and gender matched general populations.

MATERIALS AND METHODS

We identified all patients with primary low risk cancer at our institution. We excluded those with adverse pathological features and then matched histopathology, pharmacy, hospital episode and Cancer Registry records. We reviewed case notes on patients with subsequent muscle invasion (progression) or disease specific mortality. Patients underwent post-resection surveillance and treatment using standard regimens. National and regional disease specific mortality rates were calculated from appropriate data.

RESULTS

A total of 699 patients met study inclusion criteria. Median followup was 61 months (IQR 24-105). Of the patients 17 (2.4%) died of bladder cancer, including 13 of 14 with progression to muscle invasion and 4 of 19 with grade progression to high grade, nonmuscle invasive disease. On Cox regression analyses low grade dysplasia in the initial resection specimen and tumor weight were associated with disease specific mortality (p <0.003). Disease specific mortality in these patients was 5 times the background rate in matched populations. Limitations of this study include its retrospective nature and the low frequency of adverse events.

CONCLUSIONS

Patients with low risk bladder cancer rarely progress to muscle invasion but they are at higher risk for disease specific mortality than the general population. Current surveillance regimens appear ineffective for detecting progression in time to alter prognosis.

Update on the management of non-muscle invasive bladder cancer

Non-muscle invasive bladder cancer (NMIBC) is a heterogeneous population of tumours accounting for 80% of bladder cancers. Over the years, the management of this disease has been changing with improvements in results and outcomes. In this review, we focus on the latest updates on the management of NMIBC.

Decreased galectin-8 is a strong marker for recurrence in urothelial carcinoma of the bladder

OBJECTIVE

To investigate galectin-8 expression patterns in normal urothelium and bladder cancer specimens and to elucidate its prognostic value.

MATERIALS AND METHODS

162 samples of non-muscle-invasive transitional cell carcinoma, 25 samples of muscle-invasive transitional cell carcinoma and 10 samples of normal urothelium were investigated by immunohistochemistry using tissue microarrays. Complete patient and tumor characteristics were compared with galectin-8 staining patterns. The likelihood of tumor recurrence and progression was analyzed based on a 3-year follow-up.

RESULTS

Loss of galectin-8 was associated with the likelihood of tumor recurrence in univariate (p < 0.05) and multivariate analyses (p < 0.01). No significance was observed for tumor progression. Patients whose specimens showed weak galectin-8 expression had a shorter recurrence-free interval (42 vs. 12 months; p < 0.01, log-rank test). All of the 10 normal urothelium samples showed high galectin-8 expression. Decreased staining was found to be associated with higher tumor stages and grades (p < 0.0001, one-way ANOVA). A significant difference was found comparing normal urothelium with any tumor stage (p < 0.01), pTa vs. pT1 tumors (p < 0.05) and non-muscle-invasive vs. muscle-invasive tumors (p < 0.0001).

CONCLUSIONS

Loss of galectin-8 might be an early step in the development of malignant lesions of the bladder and is a significant independent predictor of recurrence.

Low-grade papillary urothelial carcinoma of the urinary bladder: a clinicopathologic analysis of a post-World Health Organization/International Society of Urological Pathology classification cohort from a single academic center

CONTEXT

Few large cohort studies have addressed outcome in patients with noninvasive low-grade papillary urothelial carcinoma (LG-UrCa) following implementation of the 2004 World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification.

OBJECTIVE

To evaluate our cohort of LG-UrCa cases classified according to 2004 WHO/ISUP to reassess outcome and interobserver agreement.

DESIGN

Files were searched for all patients diagnosed with LG-UrCa between 1998 and 2008. All sections were reevaluated for accuracy of classification.

RESULTS

A total of 112 cases initially diagnosed as LG-UrCa were identified. Of those, 8 of 55 cases (15%) initially diagnosed by nonurologic pathologists were reclassified as high-grade papillary urothelial carcinoma and were excluded. The mean length of follow-up was 40.1 months (range, 2-113 months). Tumor recurrence was encountered in 56 of 104 patients (53.8%), including 37 (35.6%) with LG-UrCa or lower-grade tumors and 19 (18.3%) with high-grade papillary urothelial carcinoma. Of the 19 patients demonstrating grade progression, 7 (37%) also developed stage progression (invasive carcinoma, n = 5; metastatic carcinoma, n = 2). Seven patients eventually underwent radical cystectomy. None of the 104 patients died of bladder cancer. The mean number of recurrence episodes was 3.11. The mean durations of time to first recurrence and time to grade progression were 13.9 months and 25.1 months, respectively. The mean size of initial tumors was 1.73 cm. There was no significant correlation between tumor size, patient age, sex, or smoking history and the likelihood for recurrence or grade progression. A significantly higher rate of recurrence was seen in patients with multiple tumors at initial diagnosis (P = .04).

CONCLUSIONS

A tendency to underdiagnose high-grade papillary urothelial carcinoma continues to exist. More than half (53.8%) of patients with LG-UrCa developed recurrence, with an 18.3% incidence of grade progression and a 6.7% incidence of stage progression. Patients with multiple initial tumors had significantly higher risk of developing recurrence.

Y chromosome loss is a frequent early event in urothelial bladder cancer

AIMS

Y chromosome losses have been described in 10-40% of bladder cancers and were suggested to be age-related. The clinical significance of chromosome Y losses is largely unknown, since only small sets of male bladder cancer patients have been evaluated in previous studies. The aim of this study was to further clarify the potential relevance of Y chromosome losses in bladder cancer with respect to clinical outcome and patient age.

METHODS

A pre-existing bladder cancer tissue microarray (TMA) with clinical follow-up data including 516 urothelial bladder cancers from male patients was utilised in this study. Y chromosome losses were analysed by multicolour fluorescence in situ hybridisation (FISH) using a centromere Y probe and a centromere X probe. p53 immunostaining data were available for all patients from a previous study.

RESULTS

Y chromosome losses were seen in 23% of 477 interpretable cancers from male patients. There was no significant difference in patient age in tumours with (67.4 +/- 4.3 years) or without (67.3 +/- 2.3 years) Y chromosome losses (p = 0.9068). Y chromosome losses were equally frequent in tumours of all grades (p = 0.7831) and stages (p = 0.6140). There was also no association with p53 immunostaining (p = 0.4092). Y chromosome losses were not associated with survival in 224 invasive urothelial cancers (pT2-4; p = 0.2324), an increased risk for recurrences in 197 pTa tumours (p = 0.7649) or increased progression risk in 76 pT1 tumours (p = 0.4582).

CONCLUSION

The data of this study show that Y chromosome losses are frequent in urothelial bladder cancer of all grades and stages, which could imply that loss of the Y chromosome is an early event in bladder cancer development. p53 mediated genomic instability is evidently not required for the development of Y chromosome losses. Since there was no correlation between Y chromosome losses and clinical outcome, detection of Y losses has no clinical relevance in urothelial bladder cancer.

Audit of safety, efficacy, and cost-effectiveness of local anaesthetic cystodiathermy

INTRODUCTION

The aim of this study was to audit our experience of cystodiathermy under local anaesthetic (LA) at the time of flexible cystoscopy for recurrent superficial bladder transitional cell carcinoma (TCC).

PATIENTS AND METHODS

A total of 264 flexible cystoscopies were performed on patients with a past history of TCC. The number and site of recurrences were recorded and selected patients were offered cystodiathermy. Patient tolerability was noted. At follow-up, any recurrence was recorded.

RESULTS

Eighty patients (30%) had 91 procedures showing one or more recurrences. Fifty-one of the 80 patients (64%) were treated with cystodiathermy under LA. All completed treatment. Forty-five (88%) tolerated the procedure well. Forty-seven (92%) treatments were completed within 5 min. At a median follow-up of 15 weeks, 30 (59%) treated patients had no recurrence and three (6%) had recurrence at the site of treatment.

CONCLUSIONS

LA cystodiathermy is an effective and well-tolerated alternative to general anaesthetic cystodiathermy that enables treatment at the time of detection and may, thereby, reduce patient anxiety.

Maspin protein expression correlates with tumor progression in non-muscle invasive bladder cancer

Maspin is a 42-kDa protein that belongs to the family of serine protease inhibitors. It is involved in various physiological processes. In cancer tissue, Maspin was found to influence angiogenesis, tumor growth, metastasis and the prognosis of tumor patients. This study was performed to analyze the involvement of Maspin in transitional cell carcinoma of the bladder as well as its prognostic impact in a large patient cohort. Specimens from 162 non-muscle invasive bladder cancer patients (pTa, 91; pT1, 71) treated by transurethral resection with a minimum 3-year follow-up (median 58.5 months) were included in the present investigation. Tissue microarrays were constructed, and the specimens were immunohistochemically stained for Maspin protein expression. Each tissue specimen was assessed on a staining scale ranging from 0 (no staining) to 300 (strong staining) and correlated with various clinicopathological parameters. Maspin protein expression predicted progression with a sensitivity of 95% and a specificity of 70% (p<0.001). In predicting recurrence, Maspin staining showed 52% sensitivity and 67% specificity (p<0.05). Kaplan-Meier analyses were performed, and a low Maspin protein expression was correlated with a higher incidence of tumor progression (p<0.0001). However, expression levels of Maspin protein did not distinguish between pTa and pT1 specimens. Multivariate analyses indicated Maspin expression as an independent factor for predicting progression (p<0.0001) and recurrence (p<0.05). The present results suggest that the Maspin protein expression is an independent prognostic indicator for predicting recurrence and progression to muscle invasive disease. This study further emphasizes a possible clinical role of this novel tumor suppressor gene in transitional cell carcinoma of the bladder.

Prognostic significance of the 2004 WHO/ISUP classification for prediction of recurrence, progression, and cancer-specific mortality of non-muscle-invasive urothelial tumors of the urinary bladder: a clinicopathologic study of 1,515 cases

To verify prognostic significance of the 2004 World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grading systems, we retrospectively studied the tumors of 1,515 patients who underwent transurethral resection of primary non-muscle-invasive urothelial tumors (pTa, 1,006 patients; pT1, 509 patients) confined to the bladder. Cases were classified according to the 2004 WHO/ISUP systems as 212 cases of papillary urothelial neoplasm of low malignant potential (PUNLMP), 706 low-grade papillary urothelial carcinomas (LPUCs), and 597 high-grade papillary urothelial carcinomas (HPUCs). PUNLMP showed the statistically significantly lowest recurrence cumulative incidence compared with the other tumor types. There were significant differences and trends for higher progression and cancer-specific mortality cumulative incidence in the following order: PUNLMP, LPUC, pTa HPUC, and pT1 HPUC. No differences of progression and cancer-specific mortality cumulative incidence were found between pTa and pT1 LPUC. Our study validates the usefulness of the 2004 WHO/ISUP system to classify urothelial tumors into prognostically distinct categories that would contribute to the design of therapeutic and monitoring strategies for patients with non-muscle-invasive bladder urothelial tumors.

Expression signature of E2F1 and its associated genes predict superficial to invasive progression of bladder tumors

PURPOSE

In approximately 20% of patients with superficial bladder tumors, the tumors progress to invasive tumors after treatment. Current methods of predicting the clinical behavior of these tumors prospectively are unreliable. We aim to identify a molecular signature that can reliably identify patients with high-risk superficial tumors that are likely to progress to invasive tumors.

PATIENTS AND METHODS

Gene expression data were collected from tumor specimens from 165 patients with bladder cancer. Various statistical methods, including leave-one-out cross-validation methods, were applied to identify a gene expression signature that could predict the likelihood of progression to invasive tumors and to test the robustness of the expression signature in an independent cohort. The robustness of the gene expression signature was validated in an independent (n = 353) cohort.

RESULTS

Supervised analysis of gene expression data revealed a gene expression signature that is strongly associated with invasive bladder tumors. A molecular classifier based on this gene expression signature correctly predicted the likelihood of progression of superficial tumor to invasive tumor.

CONCLUSION

We present a molecular signature that can predict, at diagnosis, the likelihood of bladder cancer progression and, possibly, lead to improvements in patient therapy.