Genetic initiation, progression and prognostic markers in transitional cell carcinoma of the bladder: a summary of the structural and transcriptional changes, and the role of developmental genes

Stratification based on methylation of TBX2 and TBX3 into three molecular grades predicts progression in patients with pTa-bladder cancer

The potential risk of recurrence and progression in patients with non-muscle-invasive bladder cancer necessitates followup by cystoscopy. The risk of progression to muscle-invasive bladder cancer is estimated based on the European Organisation of Research and Treatment of Cancer score, a combination of several clinicopathological variables. However, pathological assessment is not objective and reproducibility is insufficient. The use of molecular markers could contribute to the estimation of tumor aggressiveness. We recently demonstrated that methylation of GATA2, TBX2, TBX3, and ZIC4 genes could predict progression in Ta tumors. In this study, we aimed to validate the markers in a large patient set using DNA from formalin-fixed and paraffin-embedded tissue. PALGA: the Dutch Pathology Registry was used for patient selection. We included 192 patients with pTaG1/2 bladder cancer of whom 77 experienced progression. Methylation analysis was performed and log-rank analysis was used to calculate the predictive value of each methylation marker for developing progression over time. This analysis showed better progression-free survival in patients with low methylation rates compared with the patients with high methylation rates for all markers (P<0.001) during a followup of ten-years. The combined predictive effect of the methylation markers was analyzed with the Cox-regression method. In this analysis, TBX2, TBX3, and ZIC4 were independent predictors of progression. On the basis of methylation status of TBX2 and TBX3, patients were divided into three new molecular grade groups. Survival analysis showed that only 8% of patients in the low molecular grade group progressed within 5 years. This was 29 and 63% for the intermediate- and high-molecular grade groups. In conclusion, this new molecular-grade based on the combination of TBX2 and TBX3 methylation is an excellent marker for predicting progression to muscle-invasive bladder cancer in patients with primary pTaG1/2 bladder cancer.

Does phosphorylation of cofilin affect the progression of human bladder cancer?

Background

We determined the differently expressed protein profiles and their functions in bladder cancer tissues with the aim of identifying possible target proteins and underlying molecular mechanisms for taking part in their progression.

Methods

We examined the expression of proteins by proteomic analysis and western blot in normal urothelium, non-muscle-invasive bladder cancers (NMIBCs), and muscle-invasive bladder cancers (MIBCs). The function of cofilin was analyzed using T24 human bladder cancer cells.

Results

The expression levels of 12 proteins were altered between bladder cancers and normal bladder tissues. Of these proteins, 14-3-3σ was upregulated in both NMIBCs and MIBCs compared with controls. On the other hand, myosin regulatory light chain 2, galectin-1, lipid-binding AI, annexin V, transthyretin, CARD-inhibitor of NF-κB-activating ligand, and actin prepeptide were downregulated in cancer samples. Cofilin, an actin-depolymerizing factor, was prominent in both NMIBCs and MIBCs compared with normal bladder tissues. Furthermore, we confirmed that cofilin phosphorylation was more prominent in MIBCs than in NMIBCs using immunoblotting and immunohistochemcal analyses. Epidermal growth factor (EGF) increased the phosphorylation of cofilin and elevated the migration in T24 cells. Knockdown of cofilin expression with small interfering RNA attenuated the T24 cell migration in response to EGF.

Conclusions

These results demonstrate that the increased expression and phosphorylation of cofilin might play a role in the occurrence and invasiveness of bladder cancer. We suspected that changes in cofilin expression may participate in the progression of the bladder cancer.

Analysis of factors predicting intravesical recurrence of superficial transitional cell carcinoma of the bladder without concomitant carcinoma in situ

BACKGROUND

The objective of this study was to investigate risk factors for intravesical recurrence in patients with superficial bladder cancer without concomitant carcinoma in situ (CIS).

METHODS

In this series, we analyzed data from patients with newly diagnosed superficial Ta or T1 transitional cell carcinoma (TCC) of the bladder without concomitant CIS who underwent complete transurethral resection (TUR) without any adjuvant intravesical instillation therapies. Multivariate analysis was used to determine significant risk factors affecting intravesical recurrence after TUR. Differences in clinicopathological features between primary and recurrent tumors were also characterized.

RESULTS

Among 341 patients undergoing TUR of Ta or T1 bladder cancer, 187 diagnosed as having concomitant CIS and/or treated with adjuvant intravesical therapy were excluded, and the remaining 154 were evaluated. Intravesical recurrence was detected in 64 of the 154 patients, showing a 5-year recurrence-free survival rate of 58.3%. Among several factors examined, only tumor size was significantly associated with intravesical recurrence. Multivariate analysis identified tumor size as an independent predictor for intravesical recurrence irrespective of other parameters including age, gender, multiplicity, growth pattern, grade and stage. Recurrent tumors were significantly smaller and of a lower grade and lower stage than primary tumors, despite the absence of differences in growth pattern and the multiplicity between them.

CONCLUSIONS

These findings suggest that primary tumor size could be used as a potential risk factor for predicting intravesical recurrence following TUR of superficial TCC of the bladder without concomitant CIS, and that the pathological characteristics of recurrent tumors are more favorable than those of primary tumors.

Aberrant expression and possible involvement of the leptin receptor in bladder cancer

OBJECTIVES

To explore the expression patterns and possible involvement of leptin and its receptor in the pathogenesis of urinary bladder cancer, with a focus on transitional cell carcinoma.

METHODS

Using reverse transcription-polymerase chain reaction, immunoblotting, and immunohistochemistry techniques, we correlated the expression patterns of leptin and its receptor with the occurrence of transitional cell carcinoma. We also applied transient transfection followed by BrdU labeling and immunofluorescent staining to address the effect of the leptin receptor on bladder cancer cell growth.

RESULTS

Although leptin was not detected in the bladder tissue specimens, a decreased expression of the leptin receptor was observed in most cancer tissue specimens we analyzed. Furthermore, the forced expression of the leptin receptor in T24 bladder cancer cells prevented them from entering the S phase.

CONCLUSIONS

Our data demonstrated for the first time that the leptin receptor is aberrantly expressed in bladder cancer tissue and is possibly involved in the carcinogenesis of bladder cancer.

Microstaging of pT1 transitional cell carcinoma of the bladder. Does it really differentiate two populations with different prognoses? (pT1 subcategory)

INTRODUCTION

Our objective was to evaluate the feasibility and value of microstaging in pT1 transitional cell carcinoma (TCC) of the bladder in a well-defined group of patients treated with transurethral resection (TUR) only.

MATERIALS AND METHODS

The clinical records of 152 patients who underwent TUR for the treatment of primary superficial TCC of the bladder between 1983 and 1997 were reviewed. Patients with primary carcinoma in situ and who received adjuvant intravesical treatments were excluded from study. We subclassified the pT1 tumors into two groups according to muscularis mucosae (MM) invasion (pT1 and pT1b). The recurrence and progression rate of cancers was analyzed according to the stage, grade, multiplicity and tumor size. Mean follow-up was 68 months. Estimation of the cumulative distribution of the disease-free interval in separate groups was calculated according to the Kaplan-Meier method. Multivariate analysis of the data was performed by using Cox regression method. A value of p < 0.05 was taken to be statistically significant with odds ratios.

RESULTS

Of the 152 patients, tumor stage was pTa in 62 (40.8%) patients and pT1 in 90 (59.2%) patients. Among those pT1 tumors, MM was identified in 50 (55.5%) of cases (pT1a = 34, pT1b = 16). In the remaining 40 (44.5%) patients, MM could not be assessed. Kaplan-Meier analysis revealed that recurrence and progression were statistically significant for stage, multiplicity and grade of tumor. However, multivariate analysis revealed that stage was the only prognostic factor for recurrence and progression (p = 0.0001).

CONCLUSION

The present study underscores the fact that pT1b tumors have a distinct natural history. If initial conservative treatment is selected, the patients must be followed very cautiously.

Progression to detrusor-muscle invasion in bladder carcinoma is associated with polysomy of chromosomes 1 and 8 in recurrent pTa/pT1 tumours

Transitional cell carcinoma (TCC) provides a unique model of cancer recurrence and progression. Sequential tumours (n=100) from 57 patients with an index pTa or pT1 TCC were studied using fluorescence in situ hybridisation (FISH), to determine aberrations of chromosomes 1 and 8. Thirty-seven patients experienced recurrences; eleven developed muscle invasive tumours (pT2+). Polysomy of chromosomes 1 or 8 was associated with pT1 TCC (P=0.0017 and P=0.0037, respectively), but not with recurrence. Progression was associated with polysomy of chromosomes 1 (P=0.003) and 8 (P=0.011) in pTa/pT1 recurrences, but not with stage. In conclusion, patients who subsequently developed invasive TCC (pT2+) had significantly higher rates of aneusomy (90%) in their superficial cancers than those patients who did not progress (P=0.009). Investigation of sequential tumours in patients with recurrent and progressive TCC showed that polysomy of chromosomes 1 and 8 were linked to subsequent detrusor muscle invasion, but not recurrence per se.

Proteomic strategies to reveal tumor heterogeneity among urothelial papillomas

Proteomics and immunohistochemistry were used to reveal tumor heterogeneity among urothelial papillomas (UPs) with the long term goal of predicting their biological potential in terms of outcome. First, we identified proteins that were deregulated in invasive fresh lesions as compared with normal urothelium, and thereafter we immunostained UPs with a panel of antibodies against some of the markers. Twenty-two major proteins showing variations of 2-fold or more in at least one-third of the invasive lesions were selected. Specific antibodies against several of the proteins were obtained, but only a few reacted positively in immunostaining. A panel consisting of antibodies against keratinocytes (CKs) 5, 13, 18, and 20 and markers of squamous metaplasia (CKs 7, 8, and 14) was used to probe normal urothelium and 30 UPs collected during a period of five years. Four UPs showed a normal phenotype, whereas the rest could be grouped in five major types that shared aberrant staining with the CK20 antibody. Type 1 heterogeneity (n = 4) showed preferred staining of the umbrella cells with the CK8 antibody. Type 2 (n = 11) was typified by the staining of the basal and intermediate layers with the CK20 antibody. Type 3 (n = 7) was characterized by the predominant staining of the basal cell layer with the CK5 antibody. Type 4 (n = 1) showed areas of CK7 negative cells, whereas type 5 (n = 3) showed loss of staining of the basal cells with the CK20. 29% of the patients experienced recurrences, but none progressed to invasive disease. Patients harboring phenotypic alterations in the basal cell compartment (types 3 and 5) showed the highest number of recurrences (4/7 and 2/3, respectively), and all type 3 lesions progressed to a higher degree of dedifferentiation. Even though a long term prospective study involving a larger sample size is required to assess the biological potential of these lesions, we believe that this approach will prove instrumental for revealing early phenotypic changes in different types of cancer.

Identification of loci associated with putative recurrence genes in transitional cell carcinoma of the urinary bladder

Following an earlier study linking monosomy 9 with recurrence of transitional cell carcinomas (TCCs) of the urinary bladder, 109 primary and recurrent TCCs (from 47 patients) were examined to explore genetic alterations at chromosome 9 associated with recurrence. Patient DNA was microdissected and extracted from archival tissue sections and analysed for loss of heterozygosity (LOH) at three regions on chromosome 9 where tumour suppressor genes (TSGs) are known to reside (INK 4A, DBC1, and TSC1). Patients were categorized into two groups, non-recurrent TCC (NR, n=18) and recurrent TCC (REC, n=29). It was noted that 12% of NR tumours, compared with 54% of REC primary tumours (p=0.01), had LOH at all informative markers spanning the TSC1 region. The risk of recurrence was significantly higher in patients with deleted TSC1 than in those who retained the TSC1 region (p=0.035). Levels of LOH at DBC1 or INK 4A were not significantly different in NR tumours than in REC primary tumours and recurrence-free survival was not affected by loss of either of these genes. Loss of all informative markers spanning chromosome 9 was observed in 0% of NR tumours compared with 25% of REC primary tumours (p=0.04). The probability of recurrence was also significantly increased in patients who had LOH at all informative markers spanning chromosome 9 (p=0.016), confirming earlier fluorescence in situ hybridization results. This study provides further evidence that recurrence in bladder cancer is a distinct event, with underlying molecular causes. It also identifies the TSC1 locus as a candidate for a TSG, which drives recurrence in a proportion of TCC patients. Loss of all informative markers, including those residing in the TSC1 region, spanning chromosome 9 was also linked to recurrence.

Loss of heterozygosity on chromosomes 11 and 17 are markers of recurrence in TCC of the bladder

Approximately 2/3 of patients diagnosed with superficial transitional cell carcinoma of the urinary bladder (TCC) will recur within 2 years. Loss of chromosome 9 and loss of heterozygosity (LOH) at 9q34 in index TCCs identify a subset of patients at high risk of recurrence. This study explores genetic alterations on chromosomes 4, 8, 11 and 17 as predictors of recurrence. A total of 109 carcinomas were investigated at 26 loci. DNA was extracted from microdissected archival normal/tumour tissue and was analysed for loss of heterozygosity (LOH). Fluorescent PCR was performed and genotyping carried out on a Perkin Elmer ABI377 sequencer. LOH of D11S490 or D17S928 was significantly more frequent in index carcinomas of patients who experienced recurrence compared to those with no recurrence (P = 0.004 and 0.019 respectively). These results suggest that loss of these regions is associated with recurrence of TCC. Further investigation is required to identify genes in these regions, which might be responsible for driving recurrence in TCC of the urinary bladder.

Interphase cytogenetics of bladder cancer progression: relationship between aneusomy, DNA ploidy pattern, histopathology, and clinical outcome

In the present study, different stages of transitional cell carcinoma of the bladder were analyzed by fluorescent in situ hybridization, using probes specific for pericentromeric classical satellite. Seventy primary tumors were evaluated for chromosomes 1, 7, 9, 17, and ploidy by flow cytometry. The results were correlated, after a mean follow-up period, with ploidy, histopathological characteristics, recurrence, and progression. Firstly, our data demonstrated that the sensitivity of fluorescence in situ hybridization in detecting quantitative DNA aberrations exceeds that of flow cytometry. The frequency of chromosome 1 and 9 aberrations was not significantly different in diploid and aneuploid tumors of different stage and grade. In contrast, the chromosome 7 and 17 aneusomy showed greater differences between pT1 and pT2-3 tumors (P<0.032 and P<0.0006, respectively) than between stage pTa and pT1. An increasing number of aberrations was observed in all chromosomes examined from tumors of patients that afterwards underwent cystectomy and/or had recurrent tumors. This study indicates that fluorescence in situ hybridization could be used to detect genetic changes relevant to patient outcome. These genetic changes could identify patients at high risk of recurrence and possible progression.

C-ERBB-2 gene amplification as a prognostic marker in human bladder cancer

OBJECTIVES

To evaluate c-erbB-2 gene amplification and its prognostic significance in transitional cell carcinoma of the bladder.

METHODS

Alterations in the gene copy number of c-erbB-2 were detected in 57 bladder tumor samples using a method based on the polymerase chain reaction.

RESULTS

Eighteen tumors (32%) showed gene amplification of c-erbB-2, which correlated with tumor grade and stage. A strong association of c-erbB-2 amplification with patient survival was also found. The amplification resulted in a significantly poorer prognosis among the patients with high-grade and/or invasive tumors. Multivariate analysis revealed that c-erbB-2 amplification and tumor grade were independent prognostic factors.

CONCLUSIONS

Our data indicate a possible role of the c-erbB-2 gene in the development of aggressive behavior in bladder tumors. Moreover, the use of c-erbB-2 gene amplification, together with tumor grade and stage, could provide an accurate basis for determining the prognosis of bladder cancer.