Detection of the c-myc gene product in urinary bladder cancer

Boosting bladder cancer treatment by intravesical nitazoxanide and bacillus calmette-guérin association

PURPOSE

Nitazoxanide (NTZ) has shown a promising antitumoral effect, the current study compared the anti-neoplastic effects of intravesical NTZ and BCG plus NTZ in NMIBC animal model.

METHODS

30 rats, Fisher 344 were instilled with 4 intravesical doses of 1.5 mg/kg of N-methyl-N-nitrosourea (MNU) every 15 days for BC induction. The animals were divided into 3 groups (Group BCG 10⁶ UFC - 1 mg of BCG; Group NTZ - 300 mg/kg of NTZ; Group NTZ + BCG - simultaneous treatment of BCG and NTZ) and received weekly intravesical treatment for 6 consecutive weeks. Animals were submitted to ultrasound imaging and euthanasia, their bladders were collected and histopathological, immunohistochemical tests (ki67 e c-Myc) and Western Blotting (PI3K, mTOR, and p-4E-BP) were performed.

RESULTS

Histopathological tests showed 66.67%, 62.5% and 37.5% incidence of BC in animals treated with BCG, NTZ, and NTZ + BCG, respectively. Nuclear positivity for ki-67 in BC animals were 12.4% (IC 10.1-14.6%), 13.2% (IC 10.5-15.9%) and 8.8% (IC 6.0-11.6%) in BCG, NTZ and NTZ + BCG group, respectively (p = 0.063). Between animals with carcinoma, c-Myc strong positive was 40.10% in NTZ, 32.2% in BCG and 19.90% in the NTZ + BCG group (p < 0.001). Blotting has shown mTOR (p = 0.0473) and PI3K inhibition (p = 0.0349) in the presence of BCG, added to 4-EBP inhibition in the presence of NTZ (p = 0.0004).

CONCLUSIONS

Results show the possible synergy between the gold standard BC treatment BCG and NTZ, in which multiple targets inhibition such as c-Myc and downstream mTOR, p-4E-BP and PI3K might play a role.

Prognostic Value of c-Myc Immunohistochemical Expression in Muscle Invasive Urothelial Carcinoma of the Urinary Bladder: A Retrospective Study

Objective:

This study aimed to investigate the immunohistochemical expression of c-Myc in muscle invasive urothelial carcinoma (MIUC) of the urinary bladder and to evaluate the correlation of c-Myc expression with different clinicopathological parameters and outcome, including a relatively new histopathological tumor characteristic that is the growth pattern of tumor invasion.

Methods:

A total of 66 formalin-fixed and paraffin-embedded sections of MIUC obtained from radical cystectomy specimens were enrolled. The sections were stained with c-Myc antibody using immunohistochemistry technique.

Results:

Tumor cells showed variability in nuclear c-Myc expression according to the growth pattern of invasion. The median H-score of nuclear expression of infiltrative pattern was significantly higher than that of non-infiltrative pattern (p<0.001). Nuclear expression of c-Myc in tumor tissue had a significant association with poor prognostic factors (sarcomatoid variant (p<0.001), perineural invasion (p=0.037), lymphovascular invasion (p<0.001), lymph node metastasis (p<0.001), distant metastasis (p=0.042) and advanced stage grouping (p=0.001). Kaplan Meier survival analysis demonstrated that c-Myc expression could not be significantly correlated with overall survival or disease free survival rates.

Conclusion:

Nuclear c-Myc seems to have a prominent role in epithelial to mesenchymal transition with consequential in tumor progression and metastasis, while it is not as much useful to predict the clinical behavior of patients with MIUC.

Biomarkers in Bladder Cancer: Present Status and Perspectives

Bladder cancers are a mixture of heterogeneous cell populations, and numerous factors are likely to be involved in dictating their recurrence, progression and the patient's survival. For any candidate prognostic marker to have considerable clinical relevance, it must add some predictive capacity beyond that offered by conventional clinical and pathologic parameters. Here, the current situation in bladder cancer research with respect to identification of suitable prognostic markers is reviewed. A number of individual molecular markers that might predict bladder cancer recurrence and progression have been identified but many are not sufficiently sensitive or specific for the whole spectrum of bladder cancer diseases seen in routine clinical practice. These limitations have led to interest in other molecular parameters that could enable more accurate prognosis for bladder cancer patients. Of particular interest is the epigenetic silencing of tumor suppressor genes. Since the methylation of these genes can correlate with a poor prognosis, the methylation profile may represent a new biomarker that indicates the risk of transitional cell carcinoma development. In addition, bladder cancer research is likely to be revolutionized by high-throughput molecular technologies, which allow rapid and global gene expression analysis of thousands of tumor samples. Initial studies employing these technologies have considerably expanded our ability to classify bladder cancers with respect to their survivability. Future microarray analyses are likely to reveal particular gene expression signatures that predict the likelihood of bladder cancer progression and recurrence, as well as patient's survival and responsiveness to different anti-cancer therapies, with great specificity and sensitivity.

CEBPD amplification and overexpression in urothelial carcinoma: a driver of tumor metastasis indicating adverse prognosis

The molecular aberrations responsible for the progression of urothelial carcinoma (UC) remain largely obscure. To search candidate driver oncogenes in UC, we performed array-based genomic hybridization (aCGH) on 40 UBUC samples. Amplification of 8q11.21 was preferentially identified in patients who developed disease-specific death (53.8%) and distal metastasis (50.0%) but was barely detected in non-eventful cases (3.7% and 0%, respectively). In order to quantify the expression of candidate genes harbored in 8q11.21, laser-capture microdissection coupled with RT-PCR was performed on 32 of the 40 cases submitted to aCGH. With this, we identified CEBPD mRNA expression as most significantly associated with gains of 8q11.21, suggesting amplification-driven expression. By performing CEBPD-specific FISH and immunohistochemistry on 295 UBUCs, we confirmed CEBPD amplification (21.3%) and overexpression (29.8%) were strongly related to each other (p<0.001). Moreover, both were associated with adverse clinicopathologic features and worse outcomes. Furthermore, the clinical significance of CEBPD expression was also confirmed in an independent cohort comprised of 340 UCs from the upper urinary tract. Interestingly, CEBPD knockdown suppressed cell proliferation, migration and, most significantly, cell invasion ability in UC cells. The latter phenotype is attributed to downregulation of MMP2 as identified by RT2 Profiler PCR array. Moreover, expression of CEBPD significantly enhanced MMP2 expression and transcriptional activation by directly binding to its promoter region, as confirmed by promoter reporter assay and chromatin immunoprecipitation assay. Conclusively, CEBPD amplification is a mechanism driving increased mRNA and protein expression that confers aggressiveness in UC through MMP2-mediated cell invasiveness.

The establishment of a growth-controllable orthotopic bladder cancer model through the down-regulation of c-myc expression

To properly evaluate the biological effects of immunotherapy, it is critical to utilize a model of cancer in immune-competent mice. Currently, MBT-2 is the most common murine bladder cancer cell line used in orthotopic bladder cancer models, even though this cell type often has an inappropriate genetic mutation landscape. In these models, after tumors are detected with in vivo imaging, the mouse usually dies within two to three weeks due to post-renal azotemia caused by the rapidly growing mass. This event prohibits the evaluation of tumor behavior upon intravesical drug treatment. We explored whether an shRNA-induced decrease in the expression of the c-myc oncogene in MBT-2 cells could slow down their in vitro proliferation and in vivo tumor growth. We transduced MBT-2 cells with shRNA lentiviruses that bound c-myc, established MBT2.cMYCshRNA and confirmed the retardation of the growth of tumors implanted in C3H/He mice. Accordingly, this study suggests that this novel orthotopic bladder cancer model in immune-competent mice may be more appropriate for the analysis of the effects of the intravesical instillation of immunotherapeutic agents.

Intravesical instillation of c-MYC inhibitor KSI-3716 suppresses orthotopic bladder tumor growth

PURPOSE

c-MYC is a promising target for cancer therapy but its use is restricted by unwanted, devastating side effects. We explored whether intravesical instillation of the c-MYC inhibitor KSI-3716 could suppress tumor growth in murine orthotopic bladder xenografts.

MATERIALS AND METHODS

The small molecule KSI-3716, which blocks c-MYC/MAX binding to target gene promoters, was used as an intravesical chemotherapy agent. KSI-3716 action was assessed by electrophoretic mobility shift assay, chromatin immunoprecipitation, transcription reporter assay and quantitative reverse transcriptase-polymerase chain reaction. Inhibition of cell proliferation and its mechanism was monitored by cell cytotoxicity assay, EdU incorporation assay and flow cytometry. The in vivo efficacy of KSI-3716 was examined by noninvasive luminescence imaging and histological analysis after intravesical instillation of KSI-3716 in murine orthotopic bladder xenografts.

RESULTS

KSI-3716 blocked c-MYC/MAX from forming a complex with target gene promoters. c-MYC mediated transcriptional activity was inhibited by KSI-3716 at concentrations as low as 1 μM. The expression of c-MYC target genes, such as cyclin D2, CDK4 and hTERT, was markedly decreased. KSI-3716 exerted cytotoxic effects on bladder cancer cells by inducing cell cycle arrest and apoptosis. Intravesical instillation of KSI-3716 at a dose of 5 mg/kg significantly suppressed tumor growth with minimal systemic toxicity.

CONCLUSIONS

The c-MYC inhibitor KSI-3716 could be developed as an effective intravesical chemotherapy agent for bladder cancer.

[Urine-based diagnostics: an update on the Kiel Tumor Bank]

The heterogeneity of bladder tumors in their ability to invade and metastasize and their frequent recurrence pose a challenge for physicians who treat bladder cancer patients and for the researchers who work on bladder cancer diagnosis, recurrence, and treatment-related areas. For most new bladder cancer cases, investigation begins when patients are symptomatic (i.e., hematuria or irritative voiding). This mode of detection is often inadequate for nearly 15-30% of these new cases with high-grade bladder cancer, since the tumor is already in the invasive stage at the time of diagnosis. Bladder cancer patients are on a mandatory 3-month to 6-month surveillance schedule because bladder tumors frequently recur. The current mode of detecting bladder cancer involves cystoscopy, which is an invasive and relatively expensive procedure. Voided urine cytology, the standard noninvasive marker, is highly tumor specific and has good sensitivity for detecting high-grade tumors. However, its sensitivity for detecting low-grade tumors is low; its accuracy depends on the examiner's expertise; and it is not available everywhere. Marker systems are readily available for use in practice. Their utility remains under discussion.

Molecular biomarkers in urothelial bladder cancer

Bladder cancers are a mixture of heterogeneous cell populations, and numerous factors are likely to be involved in dictating their recurrence, progression, and the patient's survival. For any candidate prognostic marker to have considerable clinical relevance, it must add some predictive capacity beyond that offered by the conventional clinical and pathological parameters. None of the biomarkers reported to date have shown sufficient sensitivity and specificity for detecting the whole spectrum of bladder cancer diseases in routine clinical practice. The limitations of established prognostic markers requires us to identify better molecular parameters that could be of interest in predicting the prognosis of bladder cancer patients, in particular, the high-risk patient groups that are at risk of progression and recurrence. Recent progress in epigenetic modification and gene silencing opened a new avenue for the identification of epigenetic markers, which appears to be more useful for cancer diagnosis and prognosis. Although epigenetic markers also have limitations, the combined epigenetic marker approach may increase sensitivity and reliability. The epigenetic silencing of tumor-suppressor genes is interesting from a clinical standpoint because of the possibility of reversing epigenetic changes and restoring gene function in a cell. In addition, microarray technology provides us with additional tools for the analysis of global gene-expression analysis of tumor samples. Future microarray analyses are likely to reveal particular gene-expression signatures that predict the likelihood of bladder cancer progression and recurrence, as well as a patient's survival and responsiveness to different anticancer therapies, with great specificity and sensitivity.

[Tumor markers for bladder cancer: up-to-date study by the Kiel Tumor Bank]

INTRODUCTION

The number of noninvasive diagnostic tests for bladder cancer has increased tremendously over the last years with a large number of experimental and commercial tests. Comparative analyses of tests for diagnosis, follow-up, and recurrence detection of bladder cancer were performed retrospectively as well as prospectively, unicentrically, and multicentrically.

METHODS

An analysis of multicentric studies with large patient numbers compared with our own Kiel Tumor Bank data is presented. The Kiel Tumor Bank data looked prospectively at 106 consecutive bladder tumor patients from the year 2006. Special focus was put on urine cytology as a reference test, as well as the commercial NMP 22 Bladder Chek.

RESULTS

The analysis of the NMP 22 Bladder Chek showed an overall sensitivity of 69% for all tumor grades and stages, with a specificity of 76%. Comparison to multicentric data with an overall sensitivity of 75% for all tumor grades and stages, with a specificity of 73%, showed results similar to those in the literature. Urine cytology showed a comparable overall sensitivity of 73% for all tumor grades and stages, with a specificity of 80%.

CONCLUSIONS

A large number of noninvasive tests for bladder cancer follow-up with reasonable sensitivity and specificity can currently be used. Because of limited numbers of prospective randomized multicentric studies, no single particular marker for bladder cancer screening can be recommended at this point in time.

Biomarkers in bladder cancer: present status and perspectives

Bladder cancers are a mixture of heterogeneous cell populations, and numerous factors are likely to be involved in dictating their recurrence, progression and the patient's survival. For any candidate prognostic marker to have considerable clinical relevance, it must add some predictive capacity beyond that offered by conventional clinical and pathologic parameters. Here, the current situation in bladder cancer research with respect to identification of suitable prognostic markers is reviewed. A number of individual molecular markers that might predict bladder cancer recurrence and progression have been identified but many are not sufficiently sensitive or specific for the whole spectrum of bladder cancer diseases seen in routine clinical practice. These limitations have led to interest in other molecular parameters that could enable more accurate prognosis for bladder cancer patients. Of particular interest is the epigenetic silencing of tumor suppressor genes. Since the methylation of these genes can correlate with a poor prognosis, the methylation profile may represent a new bio-marker that indicates the risk of transitional cell carcinoma development. In addition, bladder cancer research is likely to be revolutionized by high-throughput molecular technologies, which allow rapid and global gene expression analysis of thousands of tumor samples. Initial studies employing these technologies have considerably expanded our ability to classify bladder cancers with respect to their survivability. Future microarray analyses are likely to reveal particular gene expression signatures that predict the likelihood of bladder cancer progression and recurrence, as well as patient's survival and responsiveness to different anti-cancer therapies, with great specificity and sensitivity.

Superficial bladder cancer: part 1. Update on etiology, classification and natural history

Superficial 'nonmuscle-invasive' bladder tumors represent a heterogeneous group of cancers, which include those that are papillary in nature and limited to the mucosa (Ta), high grade, flat and confined to the epithelium (Tis) and those that invade the submucosa or lamina propria (T1). The natural history of these bladder cancers is that of disease recurrence and progression to higher grade and stage. Furthermore, recurrence and progression rates of superficial bladder cancer vary according to several tumor characteristics. The goal in the treatment of superficial bladder cancer is twofold: reducing tumor recurrence and the subsequent need for additional therapies, such as cystoscopy, transurethral resections, intravesical therapy and the morbidity associated with these treatments; and preventing tumor progression and the subsequent need for more aggressive therapy, such as radical cystectomy. The administration of intravesical chemotherapy and immunotherapy has become an important component in accomplishing these goals. This update is the first part of two articles reviewing important contemporary concepts in the etiology, classification and natural history of superficial bladder cancer, while part II of the series will review and highlight important aspects in management of superficial bladder cancer.

Role of bone morphogenetic proteins in transitional cell carcinoma cells

Bone morphogenetic proteins (BMPs) are pleiotropic growth factors that signal through an interaction with the membrane receptors-type--IA, -IB, and -II (BMP-RIA, -RIB, and -RII, respectively). Although the prototypical members of this group of growth factors were isolated as osteoinductive factors, recently accumulated data have suggested that these factors regulate malignant cells. Herein, we review the data concerning BMPs in transitional cell carcinoma cells.

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.

High-throughput tissue microarray analysis ofCMYC amplificationin urinary bladder cancer

Alterations of chromosome 8, preferentially deletions of 8p and gains of 8q, belong to the most frequent cytogenetic changes in bladder cancer. CMYC on 8q24 is a candidate oncogene in this region. Little is known about the clinical significance of CMYC copy number changes in urinary bladder cancer because its frequency is low and a limited numbers of tumors were analyzed so far. To investigate the impact of CMYC alterations on tumor progression and patient prognosis in bladder cancer, we applied FISH to a tissue microarray containing 2317 bladder cancer samples. Presence of CMYC copy number increase was associated with advanced stage and high grade. CMYC amplifications were seen in 3 of 467 pTa (0.6%), 10 of 247 pT1 (4%) and 11 of 201 pT2-4 urothelial carcinomas (5.5%; p < 0.0001), as well as in 1 of 123 G1 (0.8%), 8 of 470 G2 (1.7%) and 17 of 365 G3 urothelial carcinomas (4.7%; p < 0.0001). CMYC gains were present in 49 of 467 pTa (10.5%), 39 of 247 pT1 (15.8%) and 43 of 201 pT2-4 urothelial carcinoma (21.4%; p < 0.0001), as well as in 7 of 123 G1 (5.7%), 56 of 470 G2 (11.9%) and 72 of 365 G3 urothelial carcinomas (19.7%; p < 0.0001). CMYC copy number changes were unrelated to prognosis of bladder cancer patients. We conclude that alterations of the CMYC gene, including copy number gains and amplifications, are linked to genetically unstable bladder cancers that are characterized by a high histologic grade and/or invasive growth. Patient prognosis was not affected by CMYC gene copy number changes.

Molecular pathways in bladder cancer

The aim of this review is to provide a contemporary outline of our current understanding of the molecular and genetic events associated with tumorigenesis and the progression of bladder cancer. A comprehensive review of the literature was performed on the molecular alterations associated with transitional cell carcinoma (TCC) of the bladder. Intense research efforts are being made to better identify and characterize various bladder cancers and their true biologic potential. The need to predict which superficial tumors will recur or progress, and which invasive tumors will metastasize has led to a much better understanding of the molecular pathways associated with bladder cancer. The molecular changes that occur in TCC of the bladder are numerous and can be categorized into: (1) chromosomal alterations leading to carcinogenesis, (2) loss of cell cycle regulation accounting for cellular proliferation, and (3) metastasis, guided by events such as angiogenesis. It is becoming apparent that the accumulation of genetic and molecular changes ultimately determines a tumors phenotype and subsequent clinical behavior. At the present time, conventional histopathologic evaluation of bladder cancer (tumor grade and stage) is inadequate to accurately predict the behavior of most bladder tumors. While new laboratory techniques have allowed us to better understand how bladder cancer develops and ultimately progresses, few of these techniques are currently available for use in the clinical setting. The ultimate goal is to develop reliable prognostic markers which will accurately predict not only the expected clinical course of an individual bladder tumor but also the response of that tumor to currently available therapies. More importantly, this information may be employed in the future to dictate altogether new treatments for the prevention and/or stabilization of the early molecular events that lead to the development of bladder cancer.

Molecular biology of transitional cell carcinoma

Transitional cell carcinoma (TCC) is the fifth most common solid malignancy in the USA. Radical cystectomy will cure a substantial fraction of patients with minimally invasive TCC, but approximately 50% of patients with muscle-invasive or extravesical disease treated by radical cystectomy alone die of metastatic TCC. Transitional cell carcinoma have a diverse collection of biologic and functional characteristics. This is reflected in a differing clinical course. The limited value of established prognosticators, make the analysis of new molecular parameters of interest in predicting the prognosis of bladder cancer patients; in particular, high-risk patient groups that are at risk of progression and recurrence. Over the past decade, there had been major progress in the elucidation of the molecular genetic changes leading to the development of TCC. This review will highlight these important advances and emphasize the ways in which molecular biology is likely to affect the development of future therapies.

Molecular prognostication in bladder cancer--a current perspective

The optimal management of bladder cancer depends on the accurate assessment of the tumour's biological potential. Advances in molecular biology and cytogenetics have spurred intense research in identifying and characterising prognostic markers for patients with transitional cell carcinoma (TCC) of the bladder. The molecular changes that occur can be categorised into (1) chromosomal alterations leading to carcinogenesis, (2) cellular proliferation as a result of dysregulation of cell cycle control, and (3) growth control processes such as angiogenesis leading to metastasis. The accumulation of these changes ultimately determines a tumour's clinical behaviour and response to therapy. As the understanding of bladder cancer evolves, novel molecular markers for prognostication will make their way from the research laboratory to the clinical setting with the promise to improve patient care and outcomes.

Current understanding of the biology of advanced bladder cancer

Transitional cell carcinoma (TCC) is reported to be the fifth most common solid malignancy in the U.S. Although radical cystectomy will cure a substantial number of patients with minimally invasive TCC, many patients with deeply muscle-invasive or extravesical disease who are treated with radical cystectomy alone die of metastatic TCC, as do patients with metastatic disease. The differing clinical course and the limited value of established prognosticators make analysis of new molecular parameters of interest in predicting the prognosis of patients with bladder cancer, particularly those in high-risk groups who are at risk of disease progression and recurrence. In the current review, a comprehensive MEDLINE/PubMed search of articles pertaining to the biology of TCC from 1965 to the present was performed, as well as a bibliographic review of cross references. TCC follow the general concept of multistep carcinogenesis and proceed through two distinct genetic pathways responsible for generating different TCC morphologies, namely the inactivation of cyclin-dependent kinase inhibitors in low-grade TCC and early p53-mediated abnormalities in high-grade TCC. TCC progression correlates with genetic instability and the accumulation of collaborative genetic lesions mainly involving p53, retinoblastoma, and growth factors. The bulk of these data are derived from cases of localized/locally advanced disease and none are ready yet for routine clinical application; however, the current knowledge has led to the clinical testing of novel biologic observations in several important trials. Understanding of the molecular biology of advanced bladder cancer continues to improve. It is likely that in the new millennium, real breakthroughs in the identification and therapy of high-risk, poor-prognosis patients will come from an integration of molecular modalities in the clinical application.

Molecular aspects of bladder cancer III. Prognostic markers of bladder cancer

The current pathological and clinical parameters provide important prognostic information, yet still have limited ability to predict the true malignant potential of most bladder tumors. In the last years, investigation of the basic mechanisms involved in carcinogenesis and tumor progression by molecular biology has provided a host of markers which are of potential diagnostic or prognostic value for bladder carcinoma. These markers may serve as tools for early and accurate prediction of tumor recurrence, progression and development of metastases and for prediction of response to therapy. The precise prediction of tumor biological behavior would facilitate treatment selection for patients who may benefit from radical surgical treatment or adjuvant therapy. We provide a current, comprehensive review of the literature on bladder tumor markers with a special emphasis on their prognostic potential. The literature suggests that currently no single marker is able to accurately predict the clinical course of bladder tumors and thus would serve as a reliable prognosticator. A combination of prognostic markers could predict which superficial tumors need an aggressive form of therapy and which invasive tumors require adjuvant therapy. Altogether, the most promising markers are, at this point, Ki-67 and p53 expression as well as matrixmetalloproteinase complex and angiogenesis.

Chromosomal imbalances in small cell carcinomas of the urinary bladder

Small cell carcinomas (SCCs) represent a rare histological subtype of urinary bladder cancer. Little is known abut the genetic alterations in these tumours. To identify chromosomal aberrations that are typically present in SCC of the urinary bladder, ten tumours were analysed by comparative genomic hybridization (CGH). CGH allows screening for all relative DNA copy number gains and losses present in a tumour. SCCs of the bladder were characterized by a high number of genomic alterations (mean: 11.3 per tumour). Deletions were most frequent at 10q (7 of 10 tumours deleted), 4q, 5q (5/10 each), and 13q (4/10). These regions may carry tumour suppressor genes with relevance for this particular tumour type. Gains of DNA sequences were most prevalent at 8q (5/10), 5p, 6p, and 20q (4/10 each). High level amplifications were found at 1p22-32, 3q26.3, 8q24, and 12q14-21. These loci may pinpoint the localization of oncogenes with relevance for small cell bladder cancer. The analysis of one tumour having areas of both SCC and transitional cell carcinoma strongly suggests that SCC can develop from TCC through the acquisition of additional genetic alterations.

Over-expression and amplification of the c-myc gene in human urothelial carcinoma

To understand the mechanisms underlying increased expression of Myc protein in human urinary bladder cancer, expression of c-myc mRNA and the copy number of the c-myc gene were determined. Expression of mRNA was measured by quantitative RT-PCR in 40 urothelial carcinomas and in 18 histologically normal mucosae. Mean expression in tumors was significantly increased (3.23+/-2.63 AU vs. 1.90+/-0.95 AU, p < 0.023) and exceeded the highest level in normal mucosa in 15 (37.5%) tumors. The c-myc gene copy number was higher than in leukocytes and normal bladder mucosa in 14 of 40 tumors, but only 3 among these showed a more than 4-fold increase indicative of gene amplification. Most, but not all, tumors with elevated expression displayed an increased gene copy number (p < 0.0001). In line with other studies of the protein level, no significant association either of c-myc mRNA over-expression or of increased gene copy number with tumor stage or grade was observed. The data indicate that elevated mRNA expression as a consequence of increases in c-myc gene copy number often underlies Myc protein over-expression in bladder cancer. This increase may be a consequence of, most frequently, chromosome 8q gain and, occasionally, gene amplification, while in some tumors deregulation of mRNA expression occurs without evident changes in the c-myc gene copy number.

Predictive value of molecular alterations for the prognosis of urothelial carcinoma

Accumulation of p53 and C-Myc overexpression are frequently found in advanced urothelial carcinomas. The prevalence and predictive value of both molecular alterations was investigated in 61 patients with superficial urothelial tumors. Distinct patterns of p53 accumulation and C-Myc overexpression were observed in superficial urothelial carcinoma of different stages. For instance, 67% of carcinomata in situ displayed accumulation of p53, but only 44% showed C-Myc overexpression, whereas in pT1 tumors the corresponding percentages were 25 and 75%. Similarly, while p53 accumulation was significantly (p = 0.02) associated with tumor grade, C-Myc overexpression did not correlate with grade. In multivariate analysis, p53 accumulation was found to be an independent predictor of tumor progression (p = 0.0096), whereas C-Myc overexpression did not correlate with the course of disease. Alterations in both markers together predicted neither tumor recurrence nor tumor progression better than p53 accumulation on its own. Sufficient expression of C-Myc may be a general requirement for proliferative competence in urothelial tumors, barring its use as a predictive marker. The predictive value of p53 accumulation for tumor progression was further underlined by the finding that in a distinct group of 52 patients with progressive urothelial carcinoma 73% of the recurrent tumors displayed p53 accumulation.

Prognostic markers in bladder cancer: a contemporary review of the literature

PURPOSE

We provide a contemporary review of bladder tumor markers and summarize their role as prognostic indicators.

MATERIALS AND METHODS

A comprehensive review of the literature on prognostic markers for transitional cell carcinoma of the bladder was performed.

RESULTS

Intense research efforts are being made to identify and characterize better various bladder cancers and their true biological potential. The need to predict which superficial tumors will recur or progress and which invasive tumors will metastasize has led to the identification of a variety of potential prognostic markers. Blood group antigens, tumor associated antigens, proliferating antigens, oncogenes, peptide growth factors and their receptors, cell adhesion molecules, tumor angiogenesis and angiogenesis inhibitors, and cell cycle regulatory proteins have recently been identified. The potential clinical applications of these tumor markers are under active investigation. Recent attention has focused on which tumor markers may predict the responsiveness of a particular bladder cancer to systemic chemotherapy.

CONCLUSIONS

At present conventional histopathological evaluation of bladder cancer (tumor grade and stage) cannot predict accurately the behavior of most bladder tumors. With a better understanding of the cell cycle, and cell to cell and cell to extracellular matrix interactions as well as improved diagnostic techniques (immunohistochemistry), progress is being made to identify and characterize other potential prognostic markers for transitional cell carcinoma of the bladder. The ultimate goal is to develop reliable prognostic markers that will accurately predict not only the course but also the response of a tumor to therapy. This information may then be used to dictate more aggressive treatment for tumors that are likely to progress and less aggressive treatment for those that are unlikely to progress. In the future these biological markers may also be used in gene therapy for the treatment of bladder cancer.

Tumour cells surviving in vivo cisplatin chemotherapy display elevated c-myc expression

The c-myc oncogene has been extensively implicated in cell proliferation, cell differentiation and programmed cell death. Aberrant expression of the c-myc gene product has been observed in a range of tumours and has also been implicated in cisplatin (cis-dichlorodiammineplatinum)-mediated chemoresistance. A solid transplantable tumour model in syngeneic DA rats was subjected to treatment with cisplatin to determine the impact of such therapy on endogenous c-myc gene expression. Serially transplanted tumours were intravenously treated with a single cisplatin dose (1 mg/kg) and c-myc expression analysed 2 and 7 days after treatment. The surviving tumour cells display a significant 2-fold elevation in c-myc expression at 48 h and 7 days after treatment. Primary cell cultures have been derived from untreated in vivo tumours of the same model and subjected to treatment with a c-myc phosphorothioate antisense oligomer. Administration of 5 microM c-myc antisense oligomer directed at the initiation codon and first four codons of c-myc mRNA results in total inhibition of c-myc expression and coincident suspension of cell growth for a period of 4 days in culture. Antisense therapies directed at the c-myc gene may well prove an effective tool for treating tumours in conjunction with cisplatin as these findings show that tumour cells surviving cisplatin chemotherapy display elevated c-myc expression.

c-myc copy number gains in bladder cancer detected by fluorescence in situ hybridization

Amplification and overexpression of c-myc have been suggested as prognostic markers in human cancer. To assess the role of c-myc gene copy number alterations in bladder cancer, 87 bladder tumors were examined for c-myc aberrations by fluorescence in situ hybridization. Dual labeling hybridization with a repetitive pericentromeric probe specific for chromosome 8 and a probe for the c-myc locus (at 8q24) was performed to analyze c-myc copy number in relation to chromosome 8 copy number on a cell by cell basis. A clear-cut c-myc amplification (up to 40 to 150 copies per cell) was found in 3 tumors. There was a low level c-myc copy number increase in 32 of the remaining 84 tumors. There was no association of low level c-myc copy number increase with c-myc protein overexpression. This suggests that a c-myc gene copy number gain as detected by fluorescence in situ hybridization does not necessarily reflect a disturbed c-myc gene function but may indicate a structural chromosome 8 abnormality including gain of distal 8q. The strong association of low level c-myc (8q) gains with tumor grade (P < 0.0001), stage (P < 0.0001), chromosome polysomy (P < 0.0001), p53 protein expression (P = 0.0019), p53 deletion (P = 0.0403), and tumor cell proliferation (Ki67 labeling index; P = 0.0021) is consistent with a role of chromosome 8 alterations in bladder cancer progression.

Expression of tumour-suppressor gene Rb, apoptosis-suppressing protein Bcl-2 and c-Myc have no independent prognostic value in renal adenocarcinoma

The expression of retinoblastoma (Rb), c-Myc and Bcl-2 proteins was studied by immunohistochemical methods in 104 cases of renal adenocarcinoma. One tumour was completely negative for Rb protein and altered expression pattern was detected in 36% of cases. A low fraction of Rb-positive nuclei was related to high grade (P = 0.016) and high mitotic index (P = 0.012). Twenty-eight per cent of the tumours expressed c-Myc in cancer cell nuclei and 87% showed cytoplasmic positivity. Cytoplasmic expression of c-Myc was related to high grade (P = 0.002), while nuclear expression of c-Myc was related to small tumour diameter (P = 0.034), low T category (P = 0.04), low mitotic index (P = 0.019) and expression of c-ErbB-2 (P = 0.0007). Overexpression of c-myc predicted favourable outcome in M0 tumours (P = 0.0157). Bcl-2 was expressed in 20% of tumours and it was related to small tumour size (P < 0.0001), low T category (P < 0.0001), lack of venous invasion (P = 0.008), node negativity (P = 0.015) and absence of metastasis (P = 0.017). In multivariate analysis the expression of Rb, Bcl-2 and c-Myc had no independent prognostic value over T category (P < 0.001), mitotic index (P = 0.008) and combined nuclear grade (P = 0.056).

Expression of c-myc protein is related to cell proliferation and expression of growth factor receptors in transitional cell bladder cancer

Archival biopsy specimens from transitional cell bladder tumours (n = 185) were analysed immunohistochemically for expression of c-myc protein. The results were compared with histopathological and clinical parameters and survival. Forty-three per cent of the tumours were negative for c-myc protein and weak, moderate, or strong cytoplasmic expression was found in 34, 14, and 9 per cent of cases, respectively. Nuclear positivity for c-myc protein was detected in 35 per cent of tumours and nuclear positivity was related to overexpression of c-erb B-2 (P = 0.01) and a high proportion of nuclei were also positive for p53 oncoprotein (p < 0.05). Cytoplasmic expression of c-myc protein was related to histological grade (P = 0.005), papillary status (P = 0.007), the S-phase fraction (P = 0.008), the mitotic index (P = 0.021), overexpression of epidermal growth factor receptor (P = 0.045), and c-erb B-2 (P = 0.17). Expression of c-myc protein was not significantly related to the progression of tumours and it had no prognostic value in survival analysis. Independent predictors were the T-category (P < 0.001), papillary status. (P = 0.001), and S-phase fraction (P = 0.061). The results show that while c-myc gene product participates in growth regulation of human bladder cancer cells, it has no independent prognostic significance.

Enhancement of sensitivity of urinary bladder tumor cells to cisplatin by c-myc antisense oligonucleotide

BACKGROUND

Tumor cells have different degrees of sensitivity and resistance to anticancer agents. The acquisition of drug resistance is a major concern in cancer treatment. Because the c-myc oncogene has been implicated in the poor prognosis of some human tumors including urinary bladder tumor (UBT), the resistance of such tumors to anticancer drugs may correlate with c-myc expression. The present study tested this hypothesis by examining the effect of c-myc antisense oligonucleotide treatment on the sensitivity of human UBT cells to anticancer chemotherapeutic agents.

METHODS

Cytotoxicity determined by a 1-day microculture tetrazolium dye assay. C-myc mRNA was examined by Northern blot analysis.

RESULTS

The T24 human UBT cell line constitutively expresses c-myc mRNA. Treatment of T24 cells with the c-myc antisense oligonucleotide resulted in a significant inhibition of the expression of c-myc mRNA. Treatment of T24 cells with the c-myc antisense oligonucleotide in combination with mitomycin C, Adriamycin, or 5-fluorouracil (5-FU) did not overcome their resistance to these anticancer chemotherapeutic agents. However, combination treatment with the c-myc antisense oligonucleotide and CDDP resulted in a synergistic cytotoxic effect on T24 cells and two freshly derived UBT cells. Further, treatment of CDDP-resistant T24 cells (T24/CDDP) with c-myc antisense oligonucleotide and CDDP reversed the resistance. Pretreatment of T24 cells with either agent and then treatment with the second agent resulted in the same cytotoxic activity as achieved in the presence of the two agents. The combination of c-myc antisense oligonucleotide and carboplatin also resulted in a synergistic cytotoxic effect on T24 cells, and the combination of c-myc antisense oligonucleotide and trans-diamminedichloro-platinum resulted in an additive cytotoxic effect. Incubation of T24 or T24/CDDP cells with the c-myc antisense oligonucleotide increased the intracellular accumulation of CDDP, but not the accumulation of 5-FU.

CONCLUSIONS

This study demonstrates that combination treatment with c-myc antisense oligonucleotide and CDDP can overcome the CDDP-resistance of UBT cells and that the increased intracellular accumulation of CDDP by c-myc antisense oligonucleotide may play a role in the enhanced cytotoxicity obtained. The synergistic effect obtained with established UBT cells and freshly isolated UBT cells suggests that combination treatment with c-myc antisense oligonucleotide and CDDP may have clinical application in the therapy of CDDP-resistant UBT.

The changing importance of prognostic factors in bladder cancer during a long-term follow-up

A cohort of 505 patients with a transitional cell bladder cancer were followed up for over 9 years and clinical, histological and morphometric factors were related to survival. Several survival analyses were done by moving the start of the follow-up so that the first analysis started at the time of primary therapy and the last one after 9 years follow-up. T-category, WHO grade, papillary status and the density of tumour infiltrating lymphocytes had independent short-term prognostic value whereas mitotic index and standard deviation (S.D.) of nuclear area were independent long-term predictors up to 7 years after diagnosis. In papillary tumours S.D. of nuclear area and mitotic index were independent long-term predictors in contrast to T-category and WHO grade which were both short-term prognostic factors. In superficial tumours only mitotic index had independent long-term prognostic value. The results show that the prognostic information from the primary tumour biopsy specimen has long-term prognostic significance in transitional cell bladder cancer. The results particularly emphasize the importance of factors related to cancer cell proliferation as long-term predictors.