Ki-67 index enhances the prognostic accuracy of the urothelial superficial bladder carcinoma risk group classification

Non-muscle invasive bladder cancer biomarkers beyond morphology

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

Estrogen receptors in urogenital schistosomiasis and bladder cancer: Estrogen receptor alpha-mediated cell proliferation

Estrogen-like metabolites have been identified in S. haematobium, the helminth parasite that causes urogenital schistosomiasis (UGS) and in patients´ blood and urine during UGS. Estrogen receptor (ER) activation is enriched in the luminal molecular subtype bladder cancer (BlaCa). To date, the significance of ER to these diseases remains elusive. We evaluated ERα and ERβ expression in UGS-related BlaCa (n = 27), UGS-related non-malignant lesions (n = 35), and noninfected BlaCa (n = 80). We investigated the potential of ERα to recognize S. haematobium-derived metabolites by docking and molecular dynamics simulations and studied ERα modulation in vitro using 3 BlaCa cell lines, T24, 5637 and HT1376. ERα was expressed in tumor and stromal cells in approximately 20% noninfected cases and in 30% of UGS-related BlaCa, predominantly in the epithelial cells. Overall, ERα expression was associated with features of tumor aggressiveness such as high proliferation and p53 positive expression. ERα expression correlated with presence of schistosome eggs. ERβ was widely expressed in both cohorts but weaker in UGS-related cases. molecular dynamics simulations of the 4 most abundant S. haematobium-derived metabolites revealed that smaller metabolites have comparable affinity for the ERα active state than 17β-estradiol, while the larger metabolites present higher affinity. Our in vitro findings suggested that ERα activation promotes proliferation in ERα expressing BlaCa cells and that this can be reverted with anti-estrogenic therapy. In summary, we report differential ER expression between UGS-related BlaCa and noninfected BlaCa and provide evidence supporting a role of active ERα during UGS and UGS-induced carcinogenesis.

Evaluation of topoisomerase II, ki-67, and P53 expression in non-muscle-invasive urothelial carcinoma and their clinical significance

Background

Transurethral resection of tumor is the main treatment of non-muscle-invasive urothelial carcinoma, but it is associated with high rate of recurrence and/or progression and this arouses the need for adjuvant therapy. Topoisomerase II (Top II), KI-67, and P53 are proliferation and cell cycle regulation markers that may predict tumor response to therapy.

Aim

This study aimed to assess Top II, KI-67, and P53 expression and their effect on clinical outcome and response to therapy of non-muscle-invasive urothelial carcinoma.

Materials and Methods

Fifty cases of non-muscle invasive urothelial carcinoma were collected; Top II, KI-67, and P53 expression was evaluated. Patients received treatment then tumor recurrence was correlated with the expression of previous markers.

Results

There was a significant association between high Top II score, P53, and KI-67 and high tumor grade (P = 0.0001, 0.001, and 0.0001), submucosal infiltration (P = 0.0001 and 0.01), and recurrence (P = 0.01, 0.001, and 0.001).

Conclusion

Top II, P53, and KI-67 may predict tumor response to therapy and the clinical outcome in non-muscle-invasive urothelial carcinoma.

Progressive tissue biomarker profiling in non-muscle-invasive bladder cancer

INTRODUCTION

The recurrence rate of non-muscle-invasive bladder cancer (NMIBC) is up to 60% within the first year of therapy. Accurate risk stratification is necessary for patient counselling, follow-up scheduling and individualized therapeutic decision making. Current prognostic models rely on clinicopathologic features, but their discrimination remains limited when in external cohorts. Despite intense efforts regarding the value of biomarkers in prognosticating outcomes in NMIBC, clinical utility remains suboptimal. It is clear that a single biomarker is not enough for the prediction of disease recurrence. Therefore, panels of non-redundant biomarkers have been created and integrated in clinical prognostic model further research relying on high throughput technologies is required. Areas covered: We performed a systematic research of the English-language literature on tissue biomarkers for prediction of NMIBC outcomes up to December 2017. Expert commentary: Despite the essential milestones achieved in our knowledge and understanding of the molecular biology underlying NMIBC, no biomarker has been implemented together with clinical feature in clinical practice. Integration of such biomarkers into predictive and prognostic model could, however, improve our accuracy, thereby paving the way for personalized medicine in the management of NMIBC.

Prognostic value of ki67 in BCG-treated non-muscle invasive bladder cancer: a meta-analysis and systematic review

OBJECTIVES

The aim of this study was to explore the prognostic value of ki67 as a marker in patients with non-muscle invasive bladder cancer (NMIBC) treated with BCG.

METHODS

Studies were systematically retrieved from the relevant databases (Web of Science, PubMed, Cochrane Library and Embase), and the expiry date was May 2017. The research steps referred to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.

RESULTS

A total of 11 studies that complied with the inclusion criteria were included. The expression of ki67 was not statistically significantly associated with recurrence-free survival (RFS) (HR 1.331; 95% CI 0.980 to 1.809). No significant heterogeneity was found among all included studies (I² =36.7%, p=0.148). The expression of ki67 was statistically significantly associated with progression-free survival (PFS) (HR 2.567; 95% CI 1.562 to 4.219), and the overexpression of ki67 was the risk factor for PFS. Significant heterogeneity was noted among all the included studies (I² =55.6%, p=0.021). The studies that might cause heterogeneity were excluded using the Galbraith plot, and then the meta-analysis was performed again. The results showed that the expression of ki67 was still associated with PFS (HR 2.922; 95% CI 2.002 to 4.266).

CONCLUSIONS

The overexpression of ki67 was the risk factor for PFS, and the relationship between the expression of ki67 and RFS was not statistically significant in patients with NMIBC treated with BCG intravesical immunotherapy. Well-designed, prospective, with a large sample size are still needed to validate the findings.

Impact of the Ki-67 labeling index and p53 expression status on disease-free survival in pT1 urothelial carcinoma of the bladder

Background

The identification of protein biomarkers to guide treatment decisions regarding adjuvant therapies for high-risk non-muscle-invasive bladder cancer (NMIBC) has been of increasing interest. Evidence of the impact of tumor suppressor gene product p53 and cell proliferation marker Ki-67 on oncologic outcomes in bladder cancer patients at highest risk of recurrence and progression is partially contradictory. We sought to mirror contemporary expression patterns of p53 and Ki-67 in a select cohort of patients with pT1 bladder cancer.

Methods

Patients from four Northern German institutions with a primary diagnosis of pT1 bladder cancer between 2009 and 2016 and complete data regarding p53 or Ki-67 expression status were included for final analyses. Baseline patient characteristics (age, gender, age-adjusted Charlson comorbidity index) and tumor characteristics [diagnostic sequence, tumor focality, concomitant carcinoma in situ, 1973 World Health Organization (WHO) grading, lymphovascular invasion, adjuvant instillation therapy] were abstracted by retrospective chart review. Immunohistochemistry for detection of p53 and Ki-67 expression was performed according to standardized protocols. Microscopic analyses were performed by central pathologic review. First, we compared patients with positive vs. negative p53 expression and Ki-67 labeling index [>40% vs. ≤40%; cutoffs based on best discriminative ability in univariable Cox regression analysis with disease-free survival (DFS) as endpoint] with regard to baseline and tumor characteristics. Second, we evaluated the effect of biomarker positivity on DFS by plotting univariable Kaplan-Meier curves and performing uni- and multivariable Cox regression analyses.

Results

Of 102 patients with complete information on p53 status, 44 (43.1%) were p53 positive, and they more often harbored concomitant carcinoma in situ (50.0% vs. 27.6%; P=0.032) and 1973 WHO grade 3 (97.7% vs. 69.0%; P=0.001) compared to their p53 negative counterparts. Of 79 patients with complete information on Ki-67 expression status, 30 (38.0%) had a labeling index >40%. Mean Ki-67 labeling index was higher in WHO grade 3 vs. grade 2 tumors (45.8 vs. 29.7; P=0.004). At a median follow-up of 51.0 months, 31/91 patients with complete follow-up information (34.1%) suffered from disease recurrence or progression. In univariable Kaplan-Meier analyses, no difference regarding DFS was found in p53 positive vs. negative (P=0.8) or Ki-67 labeling index >40% vs. ≤40% (P=0.078) patients. In multivariable analyses, Ki-67 labeling index >40% remained an independent predictor of DFS [hazard ratio (HR), 2.66; 95% confidence interval (CI), 1.02–6.95; P=0.046], after adjusting for p53 expression and lymphovascular invasion. However, p53 status was not associated with our endpoint (P=0.8).

Conclusions

While we found an association of a Ki-67 labeling index >40% and shorter DFS in pT1 bladder cancer patients, this did not hold true for p53 positivity. Future research is needed to identify additional microscopic and molecular risk factors and biomarker panels to improve risk stratification and guide adjuvant therapies in those patients.

Significance of Ki-67 in non-muscle invasive bladder cancer patients: a systematic review and meta-analysis

Purpose

This meta-analysis evaluated the prognostic significance of Ki-67 in non-muscle invasive bladder cancer (NMIBC).

Materials and Methods

We selected 39 articles including 5,229 patients from Embase, Scopus, and PubMed searches. The primary outcomes, recurrence-free survival (RFS), progression-free survival (PFS), disease-specific survival (DSS), and overall survival (OS) were determined using time-to event hazard ratios (HRs) with 95% confidence intervals (CIs). Study heterogeneity was tested by chi-square and I² statistics. Heterogeneity sources were identified by subgroup meta-regression analysis.

Results

Two studies were prospective; 37 were retrospective. Immunohistochemistry was performed in tissue microarrays or serial sections. A wide range of antibody dilutions and Ki-67 positivity thresholds were used. Study heterogeneity was attributed to analysis results in studies of RFS (p < 0.0001). Meta-regression analysis revealed that region and analysis results accounted for heterogeneity in PFS studies (p = 0.00471, p < 0.0001). High Ki-67 expression was associated with poor RFS (pooled HR, 1.78; 95% CI, 1.48–2.15), poor PFS (pooled HR, 1.28; 95% CI, 1.13–2.15), poor DSS (pooled HR, 2.24; 95% CI, 1.47–2.15), and worse OS (pooled HR, 2.29; 95% CI, 1.24–4.22).

Conclusions

The meta-analysis found that current evidence supports the prognostic value of Ki-67 in NMIBC patients.

Loss of Stromal Antigen 2 (STAG2) Expression in Upper Urinary Tract Carcinoma: Differential Prognostic Effect According to the Ki-67 Proliferating Index

BACKGROUND

Inactivating mutation and consequent expression loss of stromal antigen 2 (STAG2, also known as SA2), a component of the cohesion complex, is one of the most common genetic aberrations in urothelial carcinoma. However, the clinicopathologic or prognostic significance of STAG2 alterations in upper tract urothelial carcinoma (UTUC) is largely unknown.

METHODS

This study immunohistochemically examined the expression of STAG2 in 171 patients with UTUC. The correlations of STAG2 loss with clinicopathologic features and patients' prognoses were examined.

RESULTS

Loss of STAG2 expression was observed in 28 cases (16%). Loss of STAG2 was significantly correlated with histological low grade, papillary architecture, noninvasive tumors, absence of concomitant carcinoma in situ, and lower Ki-67 expression. Loss of STAG2 alone was not significantly associated with patients' prognoses in either the uni- or multivariate analysis. However, STAG2 loss was significantly associated with worse clinical outcome in UTUC with high Ki-67 proliferation indexes, but not in UTUC with low Ki-67 expression.

CONCLUSIONS

Loss of STAG2 was generally associated with less aggressive features in UTUC. However, the STAG2 loss was an ominous sign in the subpopulation with higher Ki-67 proliferation indexes. Examining both STAG2 and Ki-67 status may be useful for identifying aggressive clinical behavior of UTUC.

High Ki-67 Immunohistochemical Reactivity Correlates With Poor Prognosis in Bladder Carcinoma: A Comprehensive Meta-Analysis with 13,053 Patients Involved

Ki-67 is considered as one of prime biomarkers to reflect cell proliferation and immunohistochemical Ki-67 staining has been widely applied in clinical pathology. To solve the widespread controversy whether Ki-67 reactivity significantly predicts clinical prognosis of bladder carcinoma (BC), we performed a comprehensive meta-analysis by combining results from different literature. A comprehensive search was conducted in the Chinese databases of WanFang, China National Knowledge Infrastructure and Chinese VIP as well as English databases of PubMed, ISI web of science, EMBASE, Science Direct, and Wiley online library. Independent studies linking Ki-67 to cancer-specific survival (CSS), disease-free survival (DFS), overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were included in our meta-analysis. With the cut-off values literature provided, hazard ratio (HR) values between the survival distributions were extracted and later combined with STATA 12.0. In total, 76 studies (n = 13,053 patients) were eligible for the meta-analysis. It was indicated in either univariate or multivariate analysis for survival that high Ki-67 reactivity significantly predicted poor prognosis. In the univariate analysis, the combined HR for CSS, DFS, OS, PFS, and RFS were 2.588 (95% confidence interval [CI]: 1.623-4.127, P < 0.001), 2.697 (95%CI: 1.874-3.883, P < 0.001), 2.649 (95%CI: 1.632-4.300, P < 0.001), 3.506 (95%CI: 2.231-5.508, P < 0.001), and 1.792 (95%CI: 1.409-2.279, P < 0.001), respectively. The pooled HR of multivariate analysis for CSS, DFS, OS, PFS, and RFS were 1.868 (95%CI: 1.343-2.597, P < 0.001), 2.626 (95%CI: 2.089-3.301, P < 0.001), 1.104 (95%CI: 1.008-1.209, P = 0.032), 1.518 (95%CI: 1.299-1.773, P < 0.001), and 1.294 (95%CI: 1.203-1.392, P < 0.001), respectively. Subgroup analysis of univariate analysis by origin showed that Ki-67 reactivity significantly correlated with all 5 clinical outcome in Asian and European-American patients (P < 0.05). For multivariate analysis, however, the pooled results were only significant for DFS, OS, and RFS in Asian patients, for CSS, DFS, PFS, and RFS in European-American patients (P < 0.05). In the subgroup with low cut-off value (<20%), our meta-analysis indicated that high Ki-67 reactivity was significantly correlated with worsened CSS, DFS, OS, PFS, and RFS on univariate analysis (P < 0.05). For multivariate analysis, the meta-analysis of literature with low cut-off value (<20%) demonstrated that high Ki-67 reactivity predicted shorter DFS, PFS, and RFS in BC patients (P < 0.05). In the subgroup analysis of high cut-off value (≥20%), our meta-analysis indicated that high Ki-67 reactivity, in either univariate or multivariate analysis, significantly correlated with all five clinical outcomes in BC patients (P < 0.05). The meta-analysis indicates that high Ki-67 reactivity significantly correlates with deteriorated clinical outcomes in BC patients and that Ki-67 can be considered as an independent indicator for the prognosis by the meta-analyses of multivariate analysis.

Preclinical pharmacodynamic evaluation of antibiotic nitroxoline for anticancer drug repurposing

The established urinary antibiotic nitroxoline has recently regained considerable attention, due to its potent activities in inhibiting angiogenesis, inducing apoptosis and blocking cancer cell invasion. These features make nitroxoline an excellent candidate for anticancer drug repurposing. To rapidly advance nitroxoline repurposing into clinical trials, the present study performed systemic preclinical pharmacodynamic evaluation of its anticancer activity, including a methyl thiazolyl tetrazolium assay in vitro and an orthotopic urological tumor assay in vivo. The current study determined that nitroxoline exhibits dose-dependent anti-cancer activity in vitro and in urological tumor orthotopic mouse models. In addition, it was demonstrated that the routine nitroxoline administration regimen used for urinary tract infections was effective and sufficient for urological cancer treatment, and 2 to 4-fold higher doses resulted in obvious enhancement of anticancer efficacy without corresponding increases in toxicity. Furthermore, nitroxoline sulfate, one of the most common metabolites of nitroxoline in the urine, effectively inhibited cancer cell proliferation. This finding increases the feasibility of nitroxoline repurposing for urological cancer treatment. Due to the excellent anticancer activity demonstrated in the present study, and its well-known safety profile and pharmacokinetic properties, nitroxoline has been approved to enter into a phase II clinical trial in China for non-muscle invasive bladder cancer treatment (registration no. CTR20131716).

P53 and cancer-associated sialylated glycans are surrogate markers of cancerization of the bladder associated with Schistosoma haematobium infection

BACKGROUND

Bladder cancer is a significant health problem in rural areas of Africa and the Middle East where Schistosoma haematobium is prevalent, supporting an association between malignant transformation and infection by this blood fluke. Nevertheless, the molecular mechanisms linking these events are poorly understood. Bladder cancers in infected populations are generally diagnosed at a late stage since there is a lack of non-invasive diagnostic tools, hence enforcing the need for early carcinogenesis markers.

METHODOLOGY/PRINCIPAL FINDINGS

Forty-three formalin-fixed paraffin-embedded bladder biopsies of S. haematobium-infected patients, consisting of bladder tumours, tumour adjacent mucosa and pre-malignant/malignant urothelial lesions, were screened for bladder cancer biomarkers. These included the oncoprotein p53, the tumour proliferation rate (Ki-67>17%), cell-surface cancer-associated glycan sialyl-Tn (sTn) and sialyl-Lewisa/x (sLea/sLex), involved in immune escape and metastasis. Bladder tumours of non-S. haematobium etiology and normal urothelium were used as controls. S. haematobium-associated benign/pre-malignant lesions present alterations in p53 and sLex that were also found in bladder tumors. Similar results were observed in non-S. haematobium associated tumours, irrespectively of their histological nature, denoting some common molecular pathways. In addition, most benign/pre-malignant lesions also expressed sLea. However, proliferative phenotypes were more prevalent in lesions adjacent to bladder tumors while sLea was characteristic of sole benign/pre-malignant lesions, suggesting it may be a biomarker of early carcionogenesis associated with the parasite. A correlation was observed between the frequency of the biomarkers in the tumor and adjacent mucosa, with the exception of Ki-67. Most S. haematobium eggs embedded in the urothelium were also positive for sLea and sLex. Reinforcing the pathologic nature of the studied biomarkers, none was observed in the healthy urothelium.

CONCLUSION/SIGNIFICANCE

This preliminary study suggests that p53 and sialylated glycans are surrogate biomarkers of bladder cancerization associated with S. haematobium, highlighting a missing link between infection and cancer development. Eggs of S. haematobium express sLea and sLex antigens in mimicry of human leukocytes glycosylation, which may play a role in the colonization and disease dissemination. These observations may help the early identification of infected patients at a higher risk of developing bladder cancer and guide the future development of non-invasive diagnostic tests.

Expression and role of GPR87 in urothelial carcinoma of the bladder

The orphan GPR87 has recently been matched with its ligand LPA, which is a lipid mediator with multiple physiological functions, including cancer cell proliferation. This study aimed to clarify the role of GPR87 in urothelial carcinoma of the bladder. GPR87 expression was assessed in seven human bladder cancer cell lines. A replication-deficient recombinant adenoviral vector expressing shRNA targeting GPR87 (Ad-shGPR87), was constructed. Gene silencing was carried out using Ad-shGPR87. Immunohistochemical analysis was performed for transurethral resection of bladder tumor samples from 71 patients with non-muscle-invasive bladder cancer. We observed GPR87 expression in five of the seven cell lines, and silencing GPR87 gene expression significantly reduced cell viability. GPR87 expression was positive in 38 (54%) of 71 tumors. Ki-67 index was associated with positive GPR87 staining status (p < 0.0001). Patients with GPR87-positive tumors had shorter intravesical recurrence-free survival than those with GPR87-negative tumors (p = 0.010). Multivariate analysis revealed that GPR87 staining status was an independent prognostic parameter for intravesical recurrence (p = 0.041). Progression from non-muscle-invasive to muscle-invasive tumor was more frequently observed in patients with GPR87-positive tumors, although this trend did not reach statistical significance (p = 0.056). These results warrant further prospective studies to clarify the role of GPR87 expression in intravesical recurrence and progression in bladder cancer.

Overexpression of tumour-associated carbohydrate antigen sialyl-Tn in advanced bladder tumours

Little is known on the expression of the tumour-associated carbohydrate antigen sialyl-Tn (STn), in bladder cancer. We report here that 75% of the high-grade bladder tumours, presenting elevated proliferation rates and high risk of recurrence/progression expressed STn. However, it was mainly found in non-proliferative areas of the tumour, namely in cells invading the basal and muscle layers. STn was also found in tumour-adjacent mucosa, which suggests its dependence on a field effect of the tumour. Furthermore, it was not expressed by the normal urothelium, demonstrating the cancer-specific nature of this antigen. STn expression correlated with that of sialyltransferase ST6GalNAc.I, its major biosynthetic enzyme. The stable expression of ST6GalNAc.I in the bladder cancer cell line MCR induced STn expression and a concomitant increase of cell motility and invasive capability. Altogether, these results indicate for the first time a link between STn expression and malignancy in bladder cancer. Hence, therapies targeting STn may constitute new treatment approaches for these tumours.

A novel molecular grading model: combination of Ki67 and VEGF in predicting tumor recurrence and progression in non-invasive urothelial bladder cancer

PURPOSE

To assess efficacy of Ki67 combined with VEGF as a molecular grading model to predict outcomes with non-muscle invasive bladder cancer (NMIBC).

MATERIALS

72 NMIBC patients who underwent transurethral resection (TUR) followed by routine intravesical instillations were retrospectively analyzed in this study. Univariate and multivariate analyses were performed to confirm the prognostic values of the Ki67 labeling index (LI) and VEGF scoring for tumor recurrence and progression.

RESULTS

The novel molecular grading model for NMIBC contained three molecular grades including mG1 (Ki67 LI≤25%, VEGF scoring≤8), mG2 (Ki67 LI>25%, VEGF scoring≤8; or Ki67 LI≤25%, VEGF scoring>8), and mG3 (Ki67 LI>25%, VEGF scoring>8), which can indicate favorable, intermediate and poor prognosis, respectively.

CONCLUSIONS

The described novel molecular grading model utilizing Ki67 LI and VEGF scoring is helpful to effectively and accurately predict outcomes and optimize personal therapy.

Claudins and ki-67: potential markers to differentiate low- and high-grade transitional cell carcinomas of the urinary bladder

Updated classification of urothelial cell cancer differentiates low-grade and high-grade cancers, which determines potential clinical outcome. Substantial interobserver variability necessitates new biomarkers to ensure classification. Claudins' specific expression pattern characterizes normal tissues, different tumor types, and defined grades of tumor differentiation. The aim of this study was to examine the expression pattern of claudins and proliferation marker Ki-67 in low-grade and high-grade urothelial cell cancers compared with independent control samples of non-tumorous urothelium, as well as to reveal the predictive usefulness of claudins. The expression of claudins-1, -2, -3, -4, -5, -7, and -10 and Ki-67 was studied with quantitative immunohistochemistry and real-time RT-PCR with relative quantification in 103 samples: 86 urothelial cell cancers (27 low grade, 59 high grade) and 17 non-tumorous urothelia. Results were analyzed regarding overall survival and recurrence-free period as well. High-grade tumors overall showed significantly higher claudin-4 and Ki-67 and significantly lower claudin-7 expression when compared with low-grade ones. High-grade tumors revealed significantly shorter overall survival in Kaplan-Meier analysis. Claudin-4, claudin-7, and Ki-67 might be used as potential markers to differentiate low-grade and high-grade urothelial cell cancers, thereby possibly enhancing accuracy of pathological diagnosis and adding further information to clinical outcome.

Enhanced antitumor effect of coincident intravesical gemcitabine plus BCG therapy in an orthotopic bladder cancer model

OBJECTIVES

To evaluate the antitumor effect of the coincident administration of intravesical gemcitabine (Gem) plus bacillus Calmette-Guérin (BCG) in an orthotopic bladder cancer model.

METHODS

We evaluated the cytotoxic effect of gemcitabine against MBT-2 cells in vitro. Orthotopic tumors were established by implanting MBT-2 cells into the bladder of syngeneic female C3H mice. Intravesical Gem administration was evaluated at various doses: 0 mg (control); 1, 2, 4, and 8 mg (n = 8 for each group). Next, a comparative evaluation of tumor growth among the control, Gem-alone, BCG-alone, and combined Gem + BCG groups was performed (n = 16 for each group). Therapy was administered at 3-day intervals starting on day 5 and repeated 6 times. To evaluate the proliferative activity among the groups, Ki-67 immunostaining of the tumor was performed.

RESULTS

Gemcitabine exhibited a dose-dependent antitumor effect. Of the 8 mice in each group treated with a dose of 0, 1, 2, 4, or 8 mg of Gem, 1, 4, 4, 4, 5, and 4 mice failed to develop tumors and survived, respectively. The combination of Gem + BCG (54.1 ± 9.4 days) provided a significant survival advantage compared with BCG-alone (39.0 ± 16.4 days) (P = .02). Ki-67 expression, representing tumor proliferation, was significantly lower in the combined Gem + BCG group than in the BCG-alone group (P < .01).

CONCLUSIONS

Our results suggest that intravesical Gem + BCG treatment induces an enhanced antitumor effect against bladder tumors.

Enhanced antitumor effect of combination intravesical mitomycin C and bacillus Calmette-Guerin therapy in an orthotopic bladder cancer model

Intravesical immunotherapy with bacillus Calmette-Guerin (BCG) is currently the most successful adjuvant agent for the treatment and/or prophylaxis of non-muscle-invasive bladder cancer (NMIBC). However, NMIBCs recur in 60-70% of cases and 30% of these recurrent tumors present with a higher grade and more invasive properties. Patients that do not respond to intravesical BCG therapy are considered to be a challenge for urologists. Thus, novel conservative possibilities should be explored. To test the efficacy of a novel therapeutic approach, we examined the antitumor effect of combination therapy by intravesical administration of mitomycin C (MMC) plus BCG, infusing the two drugs simultaneously, in an orthotopic bladder cancer model. Intravesical BCG and MMC administration showed a dose-dependent survival (n=8 per group). The combination of MMC and BCG provided a significant survival advantage compared to the BCG-alone (p=0.035) and MMC-alone groups (p=0.040) (n=8 per group). The group with combined MMC/BCG exhibited a survival period similar to that achieved with an amount eight times higher that of BCG (n=10 per group). Ki-67 labeling index of cancer cells, showing tumor proliferation, was significantly lower in the combined group compared to the BCG-alone (p<0.05), MMC-alone (p<0.01) and control groups (p<0.01). No difference was detected between the combined group and the BCG-alone group with regard to CD3, T-cell infiltration and CD68 macrophage activity. The combined MMC/BCG treatment decreased the tumor appearance rate, improved the survival period and reduced the cellular proliferation rate in tumors compared to the BCG-alone treatment. The results suggest that the combined intravesical MMC/BCG treatment induced an enhanced antitumor effect against bladder tumors. The combined MMC/BCG treatment also showed a survival period similar to that achieved using a dose eight times higher of BCG-alone.

Biological similarities between murine chemical-induced and natural human bladder carcinogenesis

The present study investigated the similarities between rodent and human urothelial carcinogenesis models using DNA content, p53 and Ki-67 immunoexpression as surrogate markers of bladder carcinogenesis. Following N-butyl-N-(4-hydroxybutyl)-nitrosamine exposure, 49 human cystectomy specimens of bladder cancer and 53 rat bladder specimens were studied. All of the tumours and adjacent mucosa present in each specimen were evaluated. High similarities were observed between the rodent urothelium carcinogenesis process and the corresponding process in humans, in regards to the histopathological features and biological alteration profile: DNA aneuploidy, p53 overexpression and high proliferative index measured by Ki-67 immunoexpression. Despite these similarities, a higher frequency of alterations was observed in earlier stages in the rat chemical-induced carcinogenesis, namely in 5c aneuploid cells, p53 overexpression and higher Ki-67 labelling index. These results confirm that this experimental animal model is a suitable and reproducible model of bladder carcinogenesis, particularly in regards to high-risk non-invasive and invasive urothelial carcinomas. These features mandate its use in the identification of new molecular targets and evaluation of tumour response to new cytotoxic drugs or drug combinations in bladder cancer therapeutic intervention.

Clinical implications and prognostic values of topoisomerase-II alpha expression in primary non-muscle-invasive bladder cancer

OBJECTIVES

To investigate the association between expression levels of topoisomerase-II alpha (TOP-2alpha) and prognosis in primary non-muscle-invasive bladder cancer (NMIBC). TOP-2alpha, a marker of cell proliferation, has been assessed as a prognostic indicator in several types of cancer. However, currently available data on the role of TOP-2alpha in prognosis are inconsistent.

METHODS

Top-2alpha messenger ribonucleic acid (mRNA) levels were examined in 103 tumor specimens from patients with primary NMIBC by real-time polymerase chain reaction. Immunohistochemical staining was performed on 39 matched tumor samples. The median follow-up period for all patients was 51.8 months (range, 3.2-137).

RESULTS

The mRNA expression levels of TOP-2alpha were significantly elevated in subjects with high-grade (P<.001) and high-stage (P=.041) tumors as compared with subjects with low-grade and low-stage tumors. Kaplan-Meier estimates revealed significant variation in tumor recurrence and progression depending on the level of TOP-2alpha expression (log-rank test, P<.05). Multivariate Cox regression analysis revealed that the level of TOP-2alpha expression is a strong predictor of recurrence (hazard ratio, 2.507; 95% confidence interval, 1.228-5.116; P=.012) and progression (hazard ratio, 4.192; 95% confidence interval, 1.002-17.536; P=.049) for NMIBC. The results of immunohistochemical staining generally correlated with mRNA expression levels.

CONCLUSIONS

Enhanced expression of TOP-2alpha is positively associated with a high rate of recurrence and progression in NMIBC. Thus, TOP-2alpha represents a promising marker of prognosis for NMIBC.

CIS is a surrogate marker of genetic instability and field carcinogenesis in the urothelial mucosa

OBJECTIVE

To investigate whether carcinoma in situ (CIS) lesion could be considered a surrogate marker of urothelium genetic instability and field carcinogenesis or not, we evaluated DNA content, p53 overexpression, and proliferative index (Ki-67 expression) in primary tumor, in tumor-adjacent mucosa, and distant urothelial mucosa with and without presence of CIS.

PATIENTS AND METHODS

A retrospective study in radical cystectomy specimens from 49 patients was carried out. All the lesions present in each cystectomy specimen were studied, including the tumor area and the adjacent mucosa (AM). Whenever possible, the distant mucosa (DM) was also studied. When CIS was detected, this lesion and the surrounding normal mucosa were also studied. The 49 tumor areas included high grade papillary urothelial carcinoma (HGP) in 19 cases (38.8%) and invasive urothelial cell carcinomas in 30 cases (61.2%). The nuclear DNA content of cancer cells was evaluated using image cytometry allowing the determination of the DNA ploidy and 5cER parameters. The p53 and Ki-67 immunoexpression was evaluated by immunohistochemistry.

RESULTS

CIS lesions were observed in the AM and DM of both tumor groups: 15.8% and 15.4% in AM and DM, for each one of them, in HGP group and 26.7% and 22.2% in AM and DM, for each one of them, in invasive tumors group. In CIS lesion aneuploid DNA content, p53 overexpression and high proliferative labeling index were observed. The so-called normal mucosa (AM and DM) with and without focus of CIS lesions were compared for genetic instability and molecular alterations profile. Statistical differences were observed between the normal mucosa with and without CIS: the so-called normal mucosa areas with focus of CIS revealed significantly higher frequencies of DNA content alterations, p53 overexpression, and higher proliferative index. These differences were significantly different in the invasive UCC group, but this profile it is also present in HPG group.

CONCLUSION

This study points out that CIS is a marker of genetic instability of the urothelium mucosa. The CIS surrounding morphologically normal urothelium showed a high frequency of abnormal DNA content, with high percentage of clear aneuploid cells (high 5cER), p53 mutated protein expression, and a proliferative status underlying a field carcinogenesis. These alterations in normal mucosa were not found when CIS was not present.

Effect of sirolimus on urinary bladder cancer T24 cell line

Background

Sirolimus is recently reported to have antitumour effects on a large variety of cancers. The present study was performed to investigate sirolimus's ability to inhibit growth in T24 bladder cancer cells.

Methods

T24 bladder cancer cells were treated with various concentrations of sirolimus. MTT assay was used to evaluate the proliferation inhibitory effect on T24 cell line. The viability of T24 cell line was determined by Trypan blue exclusion analysis.

Results

Sirolimus inhibits the growth of bladder carcinoma cells and decreases their viability. Significant correlations were found between cell proliferation and sirolimus concentration (r = 0.830; p < 0.01) as well as between cell viability and sirolimus concentration (r = -0.896; p < 0.01).

Conclusion

Sirolimus has an anti-proliferation effect on the T24 bladder carcinoma cell line. The information from our results is useful for a better understanding sirolimus's anti-proliferative activity in the T24 bladder cancer cell line.

Large-scale analysis of cell cycle regulators in urothelial bladder cancer identifies p16 and p27 as potentially useful prognostic markers

AIMS

We investigated the value of multiple cell cycle markers for their prognostic impact on overall survival and recurrence-free survival in urothelial carcinoma (UC).

METHODS

A tissue microarray consisting of 99 UCs was evaluated for the expression of p53, p16, p21, p27, cyclin D1, cyclin E , Bcl-2, Ki-67 and PCNA. Statistical analysis was performed applying Kaplan-Meier and Cox regression models using receiver operator characteristic curves for determination of markers' cutoffs.

RESULTS

Expression above the cutoffs of Ki-67, p53 and p27, particularly in high-grade and early-stage UC, was associated with worse overall survival, while expression of p16 indicated a better outcome in low-grade and low-stage tumors. Recurrence-free survival was better in patients with high-grade UC expressing PCNA, p16 and cyclin E, and low-grade UC expressing Bcl-2 above the cutoffs, but worse in all tumors with high Ki-67.

CONCLUSION

Cell cycle deregulation in UC is complex and the prognostic value of the various involved proteins should be differentially regarded with respect to this complexity and other tumor characteristics such as grade and stage. Our results point towards the role of p16- and p27-associated pathways in tumor progression and indicate that, by using standardized approaches for tissue antigen expression, evaluation and cutoff determination, single potentially useful prognostic markers could be identified.

[Pronostic factors on recurrence and progression of superficial bladder cancer. Risk groups (part II)]

INTRODUCTION

We try to establish risk groups combining the characteristics of each bladder tumour, for a better monitoring of these patients.

MATERIAL AND METHODS

Once known the variables implied in recurrence and progression we analyze the data to establish the extreme groups, so, the one with the worse and the one with the better prognostic, remaining a residual group that would correspond of the tumours of intermediate prognostic.

RESULTS

From the results obtained, we can establish three risk groups: Bad prognostic group (high risk) : High grade tumours (G3), isolated or associated Tis and multiple or recurrent grade 2 tumours that were recurred in less than 6 months; Intermediate prognostic group: multiple TaG1 tumours, as well as not multiple Ta-1G2 and T1GI (less than 3 tumours) and Group of low risk: Single TaG1 tumours.

DISCUSSION

According to these results the group of badly risk, involves a high risk of recurrence and progression. The most effective treatment was the BCG (bacillus Calmette-Guerin) with maintenance, requiring a long-term control, more intense in the 2 first years after the RTU. In the group of intermediate risk, the rates of long-term superficial recurrence were as high as those of the high risk group, being needed a long-term control, in this group was effective the treatment with chemotherapy or BCG being preferably the maintenance. Finally in the group of good risk we don't objectify progressions being the time to the recurrence the longest one, with stabilization of the rate of recurrences after one year.

Prediction of recurrence in Ta urothelial cell carcinoma by real-time quantitative PCR analysis: a microarray validation study

Accurate prediction of tumor recurrence in patients with superficial urothelial cell carcinoma (UCC) might result in a significant reduction of invasive follow-up cystoscopies. A recent study identified a panel of 26 genes from a large cDNA microarray analysis of bladder tumors that discriminated between early- and late-recurring patients with superficial Ta tumors (Dyrskjøt et al., Nat Genet 2003;33:90-6). We aimed to validate this panel of genes in 44 primary Ta UCCs (23 and 21 tumors from patients with short or prolonged recurrence-free periods, respectively), by real-time quantitative PCR. Statistical analysis showed marginal significant different mRNA expression levels between the 2 patient groups. To evaluate a supplementary effect of genes for the identification of patients with short or prolonged recurrence-free intervals, forward logistic regression analysis was applied. This revealed that a combination of the expression profiles of the genes HNRPK, LTB4DH and ANP32B resulted in the best performance, although the combination only marginally increased the predictive value of HNRPK alone. Comparing the receiver-operating-characteristic curves for HNRPK expression among patients with short or prolonged recurrence-free periods, revealed an area under the curve of 0.696 (95% CI, 0.537-0.855). Using the median HNRPK expression level as cut-off, a sensitivity of 69.6% and a specificity of 71.4% were obtained for the identification of patients with short or prolonged recurrence-free periods, respectively. In conclusion, we were not able to confirm the microarray gene expression pattern of the 26 genes shown by Dyrskjøt et al. The discovery of accurate recurrence predictive markers, therefore, remains a challenge.

Cytokeratin 20 and Ki-67 to Distinguish Carcinoma In Situ From Flat Non-neoplastic Urothelium

Urothelial carcinoma in situ (CIS) is a high-grade neoplasm and an indicator of recurrence and progression that requires specific treatment. The distinction of CIS from flat non-neoplastic urothelium, in particular dysplasia, on the basis of histologic features is often difficult, and this study aims to validate cytokeratin 20 (CK20) and Ki-67 as discriminatory markers for this purpose. Immunostaining of these markers was applied to 26 cases of CIS, 14 atypia of unknown significance, 4 dysplasia, 6 normal, and 9 hyperplastic urothelium. CIS showed CK20 staining of deep urothelial cells in 23/26 CIS compared with restricted staining in surface cells in all non-neoplastic lesions. CIS had significantly increased Ki-67 index with a mean of 53.37% compared with that of non-neoplastic urothelium, which was <10% (P<0.0001). The proliferating cells were distributed randomly in CIS, whereas in non-neoplastic urothelium, staining was confined to the basal layer. Among the cases of atypia, 3/14 displayed deep staining for CK20 and 6/14 had elevated Ki-67 counts. In dysplasia similar findings were present in 1/4 and 2/4 cases, respectively. These findings suggest that CK20 and Ki-67 are objective markers to distinguish CIS from non-neoplastic urothelium. In cases of "atypia of unknown significance" and "dysplasia," positivity for both markers should raise the possibility of CIS or preneoplastic change and identify those cases for follow-up.

Bladder cancer diagnosis and recurrence prognosis: Comparison of markers with emphasis on survivin

Expression of the anti-apoptotic protein survivin is hardly detectable or even absent in many differentiated adult tissues, but is upregulated in almost any type of cancer. Furthermore, high survivin mRNA or protein expression generally correlates with an adverse disease course. Both these important features of survivin expression have been investigated for diagnostic and prognostic purposes in many human cancers, including bladder cancer. In this review, the role of survivin in the detection of bladder tumors and the prediction of tumor recurrence in patients with superficial bladder cancer will be discussed and compared to that of other markers/tests. The most promising marker(s) will be outlined. Also, important requirements for a successful implementation of such markers in a hospital setting are discussed. Finally, future directions for the discovery of new diagnostic or prognostic candidate markers will be mentioned.

Cadherina E, Catenina Beta, Antígeno Ki-67 y proteína p53 en el pronóstico de la recidiva tumoral en los tumores superficiales de vejiga T1

INTRODUCTION

The natural history of the superficial carcinoma of bladder is characterized by his high rate of recurrence and by the aptitude to progress to higher stages. We are going to investigate the capacity of prediction for tumor recurrence of protein p53, antigen Ki-67, E Cadherin and Beta Catenin

MATERIAL AND METHOD

88 T1 tumors with a median of free time of disease of 36 months. 58% of the serie has received prophylactic treatment with BCG 81 mg. weekly for six weeks. Cut-oof level for For P53 and Ki-67 is 10 % of stained cells. For E Cadherin and Beta Catenin we have established two groups: one with the values 0-4 (negative), and other one with the values 5-8 (positive).

RESULTS

Recurrence rate 31%, stage progression 3%. Ki-67 expression is correlated with grade (p .002) and lymphatic permeation (p .028). Multiplicity is correlated with lack( of Cadherin and Catenin's expression. Only Ki-67 expression (p .049) and lack of Beta Catenin expression (p .039) reach statistical significance. In multivariant study only lack of Beta Catenin's expression shows independent recurrence value (p .049; O.R: 2,4-6,9)

CONCLUSIONS

The most useful prognmostic markers are Ki-67 and Catenina Beta Only Beta Catenin Beta shows independent value for tumour recurrence. Tumors wich lack expression for Catenin B or Cadherin E have lower recurrence free time.

Lycopene

Oxidative stress is now recognized as an important etiological factor in the causation of several chronic diseases including cancer, cardiovascular diseases, osteoporosis, and diabetes. Antioxidants play an important role in mitigating the damaging effects of oxidative stress on cells. Lycopene, a carotenoid antioxidant, has received considerable scientific interest in recent years. Epidemiological, tissue culture, and animal studies provide convincing evidence supporting the role of lycopene in the prevention of chronic diseases. Human intervention studies are now being conducted to validate epidemiological observations and to understand the mechanisms of action of lycopene in disease prevention. To obtain a better understanding of the role of lycopene in human health, this chapter reviews the most recent information pertaining to its chemistry, bioavailability, metabolism, role in the prevention of prostate cancer and cancer of other target organs, its role in cardiovascular diseases, osteoporosis, hypertension, and male infertility. A discussion of the most relevant molecular markers of cancer is also included as a guide to future researchers in this area. The chapter concludes by reviewing global intake levels of lycopene, suggested levels of intake, and future research directions.

Prognostic markers for bladder cancer: International Consensus Panel on bladder tumor markers

The International Consensus Panel on cytology and bladder tumor markers evaluated markers that have the ability to predict tumor recurrence, progression, development of metastases, or response to therapy or patient survival. This article summarizes those findings. The panel mainly reviewed articles listed in PubMed on various prognostic indicators for bladder cancer. Based on these studies, most of which were case-control retrospective studies, various prognostic indicators were classified into 6 groups: (1) microsatellite-associated markers, (2) proto-oncogenes/oncogenes, (3) tumor suppressor genes, (4) cell cycle regulators, (5) angiogenesis-related factors, and (6) extracellular matrix adhesion molecules. The panel concluded that although certain markers, such as Ki-67 and p53, appear to be promising in predicting recurrence and progression of bladder cancer, the data are still heterogeneous. The panel recommends that identifying definitive criteria for test positivity, a clearly defined patient population, standardization of techniques used to evaluate markers, and clearly specified endpoints and statistical methods will help to bring accurate independent prognostic indicators into the clinical management of patients with bladder cancer.

Immunohistochemical expression of p63, p53 and MIB-1 in urinary bladder carcinoma. A tissue microarray study of 158 cases

P63 is a member of the p53 family, which plays a role in the differentiation of urothelium and is supposed to play a role in urothelial carcinogenesis. P53 and MIB-1 are recognised in many studies as predictive markers of progression, but few studies in the literature have examined p63. The aims of our study were to explore the expression of p63 in bladder carcinomas and to compare this expression to p53 and MIB-1, as well as to stage and grade. Tissue microarrays were performed on 158 urothelial carcinomas (56 pTa, 45 pT1 and 57>or=pT2). Immunohistochemical studies were performed with p63, p53 and MIB-1 antibodies. In our study we observed that p63 immunostaining is present in all cell layers in papillary urothelial neoplasm of low malignant potential (PUNLMP), but partially lost in non-invasive papillary urothelial carcinoma low grade (NILGC) and in pT1/>or=pT2 bladder cancers. P53 and MIB-1 displayed lower expression in PUNLMP/NILGC vs non-invasive papillary urothelial carcinoma high grade (NIHGC)/pT1, but there was no correlation between the expression of p63, p53 and MIB-1. Our study demonstrates that p63 expression distinguishes between PUNLMP/NILGC and NIHGC/pT1 (p=4.10(5)). A statistical difference disserving pTa and pT1/>or=pT2 with a statistical significance (p<10(-6)) could also be observed. P63 should be considered as an additional biomarker that might help pathologists to classify their patients.

P53 as a prognostic marker for bladder cancer: a meta-analysis and review

BACKGROUND

P53 is the most widely investigated molecular marker in bladder cancer. We aimed to review comprehensively the evidence for use of changes in P53 to predict bladder-cancer recurrence, progression, and mortality.

METHODS

We reviewed 168 publications from 117 studies. Estimates of significance were extracted from association tests, and hazard ratios with 95% CI from actuarial curves and Cox regression analyses. A meta-analysis was done on the studies that applied Cox models.

FINDINGS

The methods used to assess significance varied widely between studies. 27% (nine of 34) of studies that assessed the prognostic value of P53 overexpression in recurrence by use of multivariate tests showed a significant association. The corresponding values for progression and mortality were 50% (12 of 24) and 29% (ten of 35), respectively. In the studies that used Cox models, the overall risk of recurrence was 1.6 (95% CI 1.2-2.1), of progression was 3.1 (1.9-4.9), and of mortality was 1.4 (1.2-1.7). These findings could be overestimates because of publication and reporting bias.

INTERPRETATION

After 10 years of research, evidence is not sufficient to conclude whether changes in P53 act as markers of outcome in patients with bladder cancer.

Molecular markers for predicting recurrence, progression and outcomes of bladder cancer (do the poster boys need new posters?)

PURPOSE OF REVIEW

Molecular markers for bladder cancer recurrence and progression continue to drive many research programmes. Translating the laboratory findings into the clinical environment where these markers are used in clinical decision making has proved problematic. In the clinical arena, stage and grade are still the main focus for decisions about patient management. There is however an evolution in bladder cancer research from single-marker/single-pathway research to a more global assessment of the tumour cell with DNA microarrays and proteomics.

RECENT FINDINGS

In the last year, DNA microarray assessment has revealed several interesting molecular markers such as p33ING1 and DEK. Parallel "conventional" single-pathway research has focused on new novel markers such as HER2/neu, survivin and matrix metalloproteinase 2 (MMP-2). Molecular markers that have a long-standing association with bladder cancer progression such as p53, E-cadherin and Ki-67 have been reviewed by both single-marker studies and by microarray studies and their status remains important.

SUMMARY

It is an exciting time in the molecular biology research of bladder cancer as the focus changes to assess the global genetic and protein expression within tumour cells. From such a wealth of information it is likely that molecular markers will make the translation from benchside to bedside.

Valor pronóstico de progresión de las moléculas reguladoras del ciclo celular en tumores vesicales T1G3

INTRODUCTION AND OBJECTIVE

Bladder tumor T1G3 constitutes the group of superficial tumors more aggressive. New prognostic factors in the field of the cytogenetics and molecular biology have been analyzed, with often contradictory results, being little the specific works in tumors T1G3. Our objective is to determine if in this group of tumors the immunohistochemical markers present predictive value of clinically useful progression, and therefore with validity to indicate more suitable a precocious therapeutic attitude.

MATERIAL AND METHODS

Retrospective study of a series of 83 patients affected of bladder tumor T1G3, on which we analyzed a total of 14 variables; between the new predictive factors: the immunohistochemical determination of regulating proteins of the cellular cycle: p53, p21 and bcl-2, as well as the Ki-67 protein like marker of cellular proliferation. By means of logistic regression analysis we establish the independent prognostic variables for tumorlike progression.

RESULTS

The cut point established for Ki67 and p53 was 40% of inmmunomarked cells, 20% for p21 and 10% for Bcl-2. The univariant analysis showed different rates from progression and free times of progression based on the immunohistochemistry of Ki67 and p53: nevertheless, the logistic regression demonstrated that single the immunohistochemistry of p53 presented independent predictive value.

CONCLUSIONS

The determination of p53 presents predictive value of clinically useful progression in bledder tumors T1G3, so that its determination can constitute a essential factor in the strategies of treatment of these tumors.

Lasermicrodissection--an important prerequisite for the molecular-genetic analysis of bladder cancer

The past 10 years have shown that a crucial point in the molecular-genetic analysis of malignant tumors is the exact histopathological definition and separation of the investigated lesions. Laser microdissection has become an important tool allowing for the study of specific histological entities and defined preneoplastic lesions. Reliable detection of tumor-specific alterations can be compromised by the presence of normal cells. This requires microdissection of pure tumor cell populations (>80%), necessary for detecting chromosomal alterations by loss of heterozygosity analysis (LOH) and fluorescence in situ hybridization (FISH). The combination of microdissection and molecular methods could also be useful for studying multifocal lesions of the urothelial tract. This article describes in detail the use of laser microdissection, whole genome amplification by Improved Primer Extension Preamplification (I-PEP)-PCR and subsequent LOH, FISH, and sequencing analyses for the investigation of urothelial tumors and their precursors, e.g. dysplasias and hyperplasias. The combination of the described methods allows for a wide spectrum of molecular investigations in lesions with a limited number of tumor cells, and might help to understand the fundamental alterations involved in urothelial carcinogenesis.