Detection of circulating uroplakin-positive cells in patients with transitional cell carcinoma of the bladder

Comparison of RNAscope and immunohistochemistry for evaluation of the UPK2 status in urothelial carcinoma tissues

BACKGROUND

UPK2 exhibits excellent specificity for urothelial carcinoma (UC). UPK2 evaluation can be useful in making the correct diagnosis of UC. However, UPK2 detection by immunohistochemistry (IHC) has relatively low sensitivity. This paper aimed to compare the diagnostic sensitivity of RNAscope and IHC for evaluation of the UPK2 status in UC.

METHODS

Tissue blocks from 127 conventional bladder UCs, 45 variant bladder UCs, 24 upper tract UCs and 23 metastatic UCs were selected for this study. IHC and RNAscope were used to detect the UPK2 status in UCs. Then, comparisons of the two methods were undertaken.

RESULTS

There was no significant difference between RNAscope and IHC for the evaluation of the UPK2 positivity rate in UC (68.0% vs. 62.6%, P = 0.141). Correlation analysis revealed a moderate positive correlation for detection of UPK2: RNAscope vs. IHC (P < 0.001, R = 0.441). Our results showed a trend toward a higher positive UPK2 rate detected by RNAscope (53.3%) than by IHC (35.6%) in variant bladder UCs. Disappointingly, the P value did not indicate a significant difference (P = 0.057).

CONCLUSIONS

RNAscope for UPK2 appeared to perform similarly to IHC, with a marginally higher positive rate, suggesting it could be used as an alternative or adjunct to UPK2 IHC.

Potential of the cell-free blood-based biomarker uroplakin 2 RNA to detect recurrence after surgical resection of lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer, and ~30% of patients with LUAD develop cancer recurrence after surgery. The present study aimed to identify and validate biomarkers that may be used to monitor recurrence following LUAD surgery. Data from patients with LUAD were downloaded from The Cancer Genome Atlas database and postoperative recurrence samples were selected. Subsequently, weighted gene co-expression network analysis (WGCNA) was subsequently performed to identify key co-expression gene modules. Additionally, enrichment analysis of the key gene modules was performed using the Database for Annotation, Visualization and Integrated Discovery. Furthermore, survival analysis was performed on the most notable biomarker, uroplakin 2 (UPK2), which was downloaded from the Oncomine database, and its effect on prognosis was assessed. WGCNA identified 39 gene modules, of which one was most associated with recurrence. Among them, UPK2, kelch domain containing 3, galanin receptor 2 and tyrosinase-related protein 1 served a central role in the co-expression network and were significantly associated with the survival of patients. A total of 132 blood samples were collected from patients with LUAD with free UPK2 in the plasma. The expression levels of UPK2 relative to GADPH were 0.1623 and 0.2763 in non-relapsed and relapsed patients, respectively. Receiver operating characteristic curve analysis was used to detect free UPK2 mRNA in the blood in order to monitor postoperative recurrence, resulting in an area under the curve of 0.767 and a 95% CI of 0.675-0.858. Patients with high free UPK2 mRNA expression had unfavorable survival outcomes compared with those with low UPK2 expression. Therefore, free UPK2 mRNA expression in the plasma may have the potential to act as an indicator of postoperative recurrence in patients with early stage LUAD.

Circulating tumor cells in bladder cancer: Emerging technologies and clinical implications foreseeing precision oncology

CONTEXT

Circulating tumor cells (CTC) in peripheral blood of cancer patients provide an opportunity for real-time liquid biopsies capable of aiding early intervention, therapeutic decision, response to therapy, and prognostication. Nevertheless, the rare and potentially heterogeneous molecular nature of CTC has delayed the standardization of robust high-throughput capture/enrichment and characterization technologies.

OBJECTIVE

This review aims to systematize emerging solutions for CTC analysis in bladder cancer (BC), their opportunities and limitations, while providing key insights on specific technologic aspects that may ultimately guide molecular studies and clinical implementation.

EVIDENCE ACQUISITION

State-of-the-art screening for CTC technologies and clinical applications in BC was conducted in MEDLINE through PubMed.

EVIDENCE SYNTHESIS

From 200 records identified by the search query, 25 original studies and 1 meta-analysis met the full criteria for selection. A significant myriad of CTC technological platforms, including immunoaffinity, biophysical, and direct CTC detection by molecular methods have been presented. Despite their preliminary nature and irrespective of the applied technology, most studies concluded that CTC counts in peripheral blood correlated with metastasis. Associations with advanced tumor stage and grade and worst prognosis have been suggested. However, the unspecific nature, low sensitivity, and the lack of standardization of current methods still constitutes a major drawback. Moreover, few comprehensive molecular studies have been conducted on these poorly known class of malignant cells.

CONCLUSION

The current rationale supports the importance of moving the CTC field beyond proof of concept studies toward molecular-based solutions capable of improving disease management. The road has been paved for identification of highly specific CTC biomarkers and novel targeted approaches, foreseeing successful clinical applications.

The current status and clinical value of circulating tumor cells and circulating cell-free tumor DNA in bladder cancer

Urothelial carcinoma of the bladder (UCB) is a complex disease, which is associated with highly aggressive tumor biologic behavior, especially in patients with muscle-invasive and advanced tumors. Despite multimodal therapy options including surgery, radiotherapy and chemotherapy, UCB patients frequently suffer from poor clinical outcome. Indeed, the potential of diverse opportunities for modern targeted therapies is not sufficiently elucidated in UCB yet. To improve the suboptimal treatment situation in UCB, biomarkers are urgently needed that help detecting minimal residual disease (MRD), predicting therapy response and subsequently prognosis as well as enabling patient stratification for further therapies and therapy monitoring, respectively. To date, decision making regarding treatment planning is mainly based on histopathologic evaluation of biopsies predominantly derived from the primary tumors and on clinical staging. However, both methods are imperfect for sufficient outcome prediction. During disease progression, individual disseminated tumor cells and consecutively metastases can acquire characteristics that do not match those of the corresponding primary tumors, and often are only hardly assessable for further evaluation. Therefore, during recent years, strong efforts were directed to establish non-invasive biomarkers from liquid biopsies. Urine cytology and serum tumor markers have been established for diagnostic purposes, but are still insufficient as universal biomarkers for decision-making and treatment of UCB patients. To date, the clinical relevance of various newly established blood-based biomarkers comprising circulating tumor cells (CTCs), circulating cell-free nucleic acids or tumor-educated platelets is being tested in cancer patients. In this review we summarize the current state and clinical application of CTCs and circulating cell-free tumor DNA originating from blood as biomarkers in patients with different UCB stages.

The prognostic and diagnostic value of circulating tumor cells in bladder cancer and upper tract urothelial carcinoma: a meta-analysis of 30 published studies

There are inconsistent conclusions in the association between circulating tumor cells (CTCs) and urothelial cancer (UC). We performed a meta-analysis to assess the prognostic and diagnostic value of CTCs in UC. We search Medline, Embase and Web of science for relevant studies. The study was set up according to the inclusion/exclusion criteria. 30 published studies with a total of 2161 urothelial cancer patients were included. Meta-analysis showed that CTC-positive was significantly associated with tumor stage (≤ II vs III, IV) (OR = 4.60, 95% CI: 2.34-9.03), histological grade (I, II vs III) (OR = 2.91, 95% CI: 1.92-4.40), metastasis (OR = 5.12, 95% CI: 3.47-7.55) and regional lymph node metastasis (OR = 2.47, 95% CI: 1.75-3.49). It was also significantly associated with poor overall survival (OS) (HR = 3.98, 95% CI: 2.20-7.21), progression/disease-free survival (PFS/DFS) (HR = 2.22, 95% CI: 1.80-2.73) and cancer-specific survival (CSS) (HR = 5.18, 95% CI: 2.21-12.13). Overall sensitivity and specificity of CTC detection assays were 0.35 (95% CI: 0.28-0.43) and 0.97 (95% CI: 0.92-0.99) respectively. In summary, our meta-analysis suggests that the presence of CTCs in the peripheral blood is an independent predictive indicator of poor outcomes for urothelial cancer patients. It can also be used as a noninvasive method for the confirmation of cancer diagnosis. More studies are required to further explore the role of this marker in clinical practice.

Circulating Biomarkers in Bladder Cancer

Bladder cancer is a molecularly heterogeneous disease characterized by multiple unmet needs in the realm of diagnosis, clinical staging, monitoring and therapy. There is an urgent need to develop precision medicine for advanced urothelial carcinoma. Given the difficulty of serial analyses of metastatic tumor tissue to identify resistance and new therapeutic targets, development of non-invasive monitoring using circulating molecular biomarkers is critically important. Although the development of circulating biomarkers for the management of bladder cancer is in its infancy and may currently suffer from lower sensitivity of detection, they have inherent advantages owing to non-invasiveness. Additionally, circulating molecular alterations may capture tumor heterogeneity without the sampling bias of tissue biopsy. This review describes the accumulating data to support further development of circulating biomarkers including circulating tumor cells, cell-free circulating tumor (ct)-DNA, RNA, micro-RNA and proteomics to improve the management of bladder cancer.

Uroplakins and their potential applications in urology

Introduction

Urothelium is a highly specialized type of epithelium covering the interior of the urinary tract. One of the structures responsible for its unique features are urothelial plaques formed from glycoprotein heteropolymers, the uroplakins. Four types of uroplakins are known – UPIa, UPIb, UPII, UPIII. Herein we review the current status of knowledge about uroplakins and discuss their potential clinical applications.

Material and methods

A PubMed search was conducted to find original and review papers about uroplakins.

Results

Uroplakins can be detected in tissue, urine and blood. The process of urothelial plaque formation is complex and its disturbances resulting in incorrect plaque formation might be responsible for some pathological states. Additionally, uroplakins might be associated with other pathological processes i.e. urothelial cancer or infections of the urinary tract.

Conclusions

Uroplakins as the end-product of urothelial cells have unique features and a complex structure. These glycoproteins can be involved in some diseases of the urinary tract and as such can be used as potential targets for intervention and markers of the disease.

Molecular markers in bladder cancer: Novel research frontiers

Bladder cancer (BC) is a heterogeneous disease encompassing distinct biologic features that lead to extremely different clinical behaviors. In the last 20 years, great efforts have been made to predict disease outcome and response to treatment by developing risk assessment calculators based on multiple standard clinical-pathological factors, as well as by testing several molecular markers. Unfortunately, risk assessment calculators alone fail to accurately assess a single patient's prognosis and response to different treatment options. Several molecular markers easily assessable by routine immunohistochemical techniques hold promise for becoming widely available and cost-effective tools for a more reliable risk assessment, but none have yet entered routine clinical practice. Current research is therefore moving towards (i) identifying novel molecular markers; (ii) testing old and new markers in homogeneous patients' populations receiving homogeneous treatments; (iii) generating a multimarker panel that could be easily, and thus routinely, used in clinical practice; (iv) developing novel risk assessment tools, possibly combining standard clinical-pathological factors with molecular markers. This review analyses the emerging body of literature concerning novel biomarkers, ranging from genetic changes to altered expression of a huge variety of molecules, potentially involved in BC outcome and response to treatment. Findings suggest that some of these indicators, such as serum circulating tumor cells and tissue mitochondrial DNA, seem to be easily assessable and provide reliable information. Other markers, such as the phosphoinositide-3-kinase (PI3K)/AKT (serine-threonine kinase)/mTOR (mammalian target of rapamycin) pathway and epigenetic changes in DNA methylation seem to not only have prognostic/predictive value but also, most importantly, represent valuable therapeutic targets. Finally, there is increasing evidence that the development of novel risk assessment tools combining standard clinical-pathological factors with molecular markers represents a major quest in managing this poorly predictable disease.

Downregulation of UPK1A suppresses proliferation and enhances apoptosis of bladder transitional cell carcinoma cells

Uroplakin 1A (UPK1A) is a specific marker of mammalian urothelium and one of major proteins contained in urothelial plaques. Many recent studies reported that UPK1A could be useful marker for diagnosis, detection and prognostic prediction of transitional cell carcinoma. However, relatively little is known about its exact roles in bladder transitional cell carcinoma (BTCC). We tried to explore the roles UPK1A plays in BTCC via the transfection of its antisense nucleotides (AS) into T24 cells to observe their changes of proliferation and apoptosis. After AS was successfully transfected into T24 cells, the percentages of proliferating T24 cells at 24 and 48 h after the treatment were 57.2 ± 6.8 and 44.7 ± 5.2%, significantly lower than that of control group, as shown by MTT (p < 0.05 and 0.01). At 24 h after transfection of AS, the percentage of apoptotic T24 cells was 26.87% measured by flow cytometry, significantly higher than that of control group (p < 0.01). Similarly, Hoechst 33258 staining showed that the percentage of apoptotic nuclei of T24 cells after 24 h treated by AS was 28.9%, significantly higher than that of control (p < 0.05). The most common and typical morphological changes of apoptosis, including shrink, pyknosis and karyorrhexis of T24 cells nuclei and DNA fragmentation were seen from Hoechst 33258 staining and DNA agarose gel electrophoresis. Taken together, inhibition of UPK1A can suppress proliferation and enhance apoptosis of BTCC T24 cells, suggesting it a potential target to treat this disease.

A newly developed uroplakin II antibody with increased sensitivity in urothelial carcinoma of the bladder

CONTEXT

Uroplakin II is a 15-kDa protein component of the urothelial plaques that enhance the permeability barrier and strength of the urothelium. Studies have shown uroplakin II messenger RNA to be expressed in bladder cancer tissues and peripheral blood of patients with urothelial carcinoma. Little is known about the protein expression of uroplakin II in urothelial carcinoma, possibly because of the absence of a commercially available uroplakin II antibody. Pathologists have used the uroplakin III antibody (AU1) to identify tumors of urothelial origin; however, the use of AU1 is limited because of its poor sensitivity.

OBJECTIVES

To evaluate a newly developed mouse monoclonal uroplakin II antibody (BC21) in urothelial carcinoma and to compare it with previously developed mouse monoclonal uroplakin III (BC17 and AU1).

DESIGN

Uroplakin II and III antibodies were optimized for staining using a horseradish peroxidase-polymer detection system and were visualized with 3,3'-diaminobenzidine.

RESULTS

BC21, BC17, and AU1 demonstrated sensitivities in urothelial carcinoma of the bladder of 79% (44 of 56), 55% (31 of 56) (P = .002), and 34% (19 of 56) (P < .001), respectively. Subsequently, the increased staining sensitivity and intensity of BC21, compared with BC17, was validated in a larger study (134 of 174; 77% and 94 of 174; 54%, respectively) (P < .001). BC21 was found to be highly specific when evaluated in various normal and neoplastic tissues, including prostatic and renal carcinomas.

CONCLUSIONS

The mouse monoclonal uroplakin II antibody (BC21) demonstrated superior sensitivity and specificity in urothelial carcinoma, compared with uroplakin III (BC17 and AU1), suggesting its advantages in the differential diagnosis of urothelial carcinoma and in the detection of tumors of unknown origin.

Bladder cancer detection and monitoring: assessment of urine- and blood-based marker tests

Bladder cancer is one of the most prevalent cancers worldwide, but the treatment and management of this disease can be very successful if the disease is detected early. The development of molecular assays that could diagnose bladder cancer accurately, and at an early stage, would be a significant advance. Ideally, such molecular assays would be applicable to non-invasively obtained body fluids, and be designed not only for diagnosis but also for monitoring disease recurrence and response to treatment. In this article, we assess the performance of current diagnostic assays for bladder cancer and discuss some of the emerging biomarkers that could be developed to augment current bladder cancer detection strategies.

Antitumor effects of bladder cancer-specific adenovirus carrying E1A-androgen receptor in bladder cancer

The high frequency of recurrence and poor survival rate of bladder cancer demand exploration of novel strategies. Gene therapy via adenovirus has shown promising potential for the treatment of tumors. We constructed a bladder cancer-specific adenovirus carrying E1A-androgen receptor (AR) under the control of UPII promoter and prostate stem cell antigen enhancer (PSCAE), designated as Ad/PSCAE/UPII/E1A-AR, and investigated its antitumor effects in vitro and in vivo. We demonstrated that Ad/PSCAE/UPII/E1A-AR could be selectively replicated in bladder tumor cell lines (5637, BIU87, EJ and T24) when compared with control adenovirus Ad/PSCAE/UPII/Luc. However, there was no evidence of cytotoxicity for normal human bladder cell line SV-HUC-1 and hepatoma cell line SMMC7721. AR agonist R1881 could strengthen the oncolytic effect of Ad/PSCAE/UPII/E1A-AR in bladder cancer cells. In addition, we demonstrated that intratumoral injection of Ad/PSCAE/UPII/E1A-AR into established subcutaneous human EJ tumors in nude mice could significantly regress the growth of tumor and markedly prolong survival for tumor-bearing mice; on the other hand, saline-treated tumors continued to grow rapidly. Our studies indicate that Ad/PSCAE/UPII/E1A-AR could effectively treat bladder cancer in vitro and in vivo. Furthermore, our findings provide a promising therapeutic modality for the treatment of bladder cancer.

Diagnostic value of circulating tumor cell detection in bladder and urothelial cancer: systematic review and meta-analysis

Background

The diagnostic value and prognostic significance of circulating tumor cell (CTC) detection in patients with bladder cancer is controversial. We performed a meta-analysis to consolidate current evidence regarding the use of CTC detection assays to diagnose bladder and other urothelial cancers and the association of CTC positivity with advanced, remote disease.

Methods

Studies that investigated the presence of CTCs in the peripheral blood of patients with bladder cancer and/or urothelial cancer were identified and reviewed. Sensitivities, specificities, and positive (LR+) and negative likelihood ratios (LR-) of CTC detection in individual studies were calculated and meta-analyzed by random effects model. Overall odds ratio of CTC positivity in patients with advanced disease versus those with organ-confined cancer was also calculated.

Results

Overall sensitivity of CTC detection assays was 35.1% (95%CI, 32.4-38%); specificity, LR+, and LR- was 89.4% (95%CI, 87.2-91.3%), 3.77 (95%CI, 1.95-7.30) and 0.72 (95%CI, 0.64-0.81). CTC-positive patients were significantly more likely to have advanced (stage III-IV) disease compared with CTC-negative patients (OR, 5.05; 95%CI, 2.49-10.26).

Conclusions

CTC evaluation can confirm tumor diagnosis and identify patients with advanced bladder cancer. However, due to the low overall sensitivity, CTC detection assays should not be used as initial screening tests.

Bladder cancer: translating molecular genetic insights into clinical practice

Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.

Disseminated and circulating tumor cells: Role in effective cancer management

Dissemination of tumor cells from primary tumors in the circulatory system is an early event in carcinogenesis. The presence of these single disseminated tumor cells (DTC) in peripheral blood, bone marrow and distant organs is the rationale for adjuvant systemic treatment. Detection of DTC in bone marrow aspirates from breast cancer patients and other solid tumors at the primary diagnosis impacts the prognosis of disease. In peripheral blood these cells are termed as circulating tumor cells (CTC). Due to technical difficulties the clinical significance of CTC detection at early stages is less established. This review focuses on available techniques for detection of DTC and CTC, recent technical advances in development of more sensitive microfluidic methods for capture of DTC and CTC and possibilities for further detection and their potential molecular characterization. Not only the clinical significance of DTC but also the presence of cancer stem cells in dissemination clearly demonstrates the need for development of sensitive technologies allowing for definition of biomarkers and molecular targets on cells in dissemination, thus eventually leading to optimization of systemic therapies.

Differentiation of a highly tumorigenic basal cell compartment in urothelial carcinoma

Highly tumorigenic cancer cell (HTC) populations have been identified for a variety of solid tumors and assigned stem cell properties. Strategies for identifying HTCs in solid tumors have been primarily empirical rather than rational, particularly in epithelial tumors, which are responsible for 80% of cancer deaths. We report evidence for a spatially restricted bladder epithelial (urothelial) differentiation program in primary urothelial cancers (UCs) and in UC xenografts. We identified a highly tumorigenic UC cell compartment that resembles benign urothelial stem cells (basal cells), co-expresses the 67-kDa laminin receptor and the basal cell-specific cytokeratin CK17, and lacks the carcinoembryonic antigen family member CEACAM6 (CD66c). This multipotent compartment resides at the tumor-stroma interface, is easily identified on histologic sections, and possesses most, if not all, of the engraftable tumor-forming ability in the parental xenograft. We analyzed differential expression of genes and pathways in basal-like cells versus more differentiated cells. Among these, we found significant enrichment of pathways comprising "hallmarks" of cancer, and pharmacologically targetable signaling pathways, including Janus kinase-signal transducer and activator of transcription, Notch, focal adhesion, mammalian target of rapamycin, epidermal growth factor receptor (erythroblastic leukemia viral oncogene homolog [ErbB]), and wingless-type MMTV integration site family (Wnt). The basal/HTC gene expression signature was essentially invisible within the context of nontumorigenic cell gene expression and overlapped significantly with genes driving progression and death in primary human UC. The spatially restricted epithelial differentiation program described here represents a conceptual advance in understanding cellular heterogeneity of carcinomas and identifies basal-like HTCs as attractive targets for cancer therapy.

Ceragenins: a class of antiviral compounds to treat orthopox infections

Eczema vaccinatum is a potentially fatal, disseminated viral skin infection that develops in individuals with atopic dermatitis after exposure to the vaccinia virus (VV). Despite advances in modern medicine, there are few options for those suffering from disseminated VV infections. Ceragenins (CSAs) are synthetic antimicrobial compounds designed to mimic the structure and function of endogenous antimicrobial peptides (AMPs). We show that CSA-13 exhibits potent antiviral activity against VV by (1) direct antiviral effects against VV; and (2) stimulating the expression of endogenous AMPs with known antiviral activity against VV. In addition, we show that a topical application of CSA-13 penetrates the skin and reduces subsequent satellite lesion formation. This suggests that treatment with CSA-13 may be an intervention for individuals with a disseminated VV skin infection.

Selection of optimal antisense accessible sites of uroplakin II mRNA for bladder urothelium

The optimal antisense accessible sites (AAS) of uroplakin II (UP II) mRNA, a specific gene expressed in bladder urothelium, were selected in order to provide a novel method for targeted therapy of transitional cell carcinoma (TCC) of bladder. The 20 mer random oligonucleotide library was synthesized, hybridized with in vitro transcripted total UP II cRNA, then digested by RNase H. After primer extension and autoradiography, the AAS of UP II were selected. The RNADraw software was used to analyze and choose the AAS with obvious stem-loop structures, according to which the complementary antisense oligonucleotides (AS-ODN) were synthesized. With the AS-ODN(0) designed only by RNADraw as a control, the AS-ODNs were transferred into UP II highly-expressing cell line RT(4). The cellular expression of UP II mRNA was detected by RT-PCR and Western blot. Twelve AAS of UP II mRNA were selected in vitro. Four AAS with stem-loop structures were chosen, locating at 558-577, 552-571, 217-236 and 97-116 bp of UP II mRNA respectively. After transfection with the corresponding AS-ODN (AS-ODN(1), AS-ODN(2), AS-ODN(3) and AS-ODN(4)) for 18 h, the UP II mRNA levels in RT(4) cells were reduced by 29.3%, 82.7%, 71.3% and 70.9%, while UP II protein levels were decreased by 20.2%, 78.5%, 65.2% and 64.4% respectively, which were significantly higher than those of AS-ODN(0) (14.3%, 12.1% respectively) (P<0.01). The AAS of UP II mRNA was effectively selected in vitro by random oligonucletide library/RNase H cleavage method in combination with computer software analysis, which had important reference values for further studying biological functions of UP II gene and targeted therapeutic strategy for TCC of bladder.

Uroplakins in urothelial biology, function, and disease

Urothelium covers the inner surfaces of the renal pelvis, ureter, bladder, and prostatic urethra. Although morphologically similar, the urothelia in these anatomic locations differ in their embryonic origin and lineages of cellular differentiation, as reflected in their different uroplakin content, expandability during micturition, and susceptibility to chemical carcinogens. Previously thought to be an inert tissue forming a passive barrier between the urine and blood, urothelia have recently been shown to have a secretory activity that actively modifies urine composition. Urothelial cells express a number of ion channels, receptors, and ligands, enabling them to receive and send signals and communicate with adjoining cells and their broader environment. The urothelial surface bears specific receptors that not only allow uropathogenic E. coli to attach to and invade the bladder mucosa, but also provide a route by which the bacteria ascend through the ureters to the kidney to cause pyelonephritis. Genetic ablation of one or more uroplakin genes in mice causes severe retrograde vesicoureteral reflux, hydronephrosis, and renal failure, conditions that mirror certain human congenital diseases. Clearly, abnormalities of the lower urinary tract can impact the upper tract, and vice versa, through the urothelial connection. In this review, we highlight recent advances in the field of urothelial biology by focusing on the uroplakins, a group of urothelium-specific and differentiation-dependent integral membrane proteins. We discuss these proteins' biochemistry, structure, assembly, intracellular trafficking, and their emerging roles in urothelial biology, function, and pathological processes. We also call attention to important areas where greater investigative efforts are warranted.

Detection of circulating tumor cells in bladder cancer patients

The methods employed for the detection of circulating bladder cancer cells (CBCs) and their use as a molecular staging tool in clinical settings are thoroughly reviewed. CBC isolation and enrichment methods are discussed according to their advantages and pitfalls along with the clinical data of PCR-based techniques used for CBC detection. In addition, we review the specificity of molecular markers that have been proposed so far for CBC identification, and we comment on the controversial clinical data, proposing laboratory approaches which may improve the clinical significance of CBC detection in bladder cancer.

Influence of the glycosaminoglycan layer on the permeation of hypericin in rat bladders in vivo

OBJECTIVE

To investigate the influence of a glycosaminoglycan (GAG) layer on the specific location of hypericin in superficial urothelial carcinoma lesions of the bladder after intravesical instillation.

MATERIALS AND METHODS

Fisher rat bladders were incubated with 15 or 30 microm hypericin for 2 h. To examine the influence of the GAG layer on the permeation of hypericin, bladders were pre-treated with chondroitinase ABC, n-dodecyl-beta-d-maltoside (DDM) or sodium dodecyl sulphate (SDS) to disrupt, or protamine to neutralise the GAG layer before incubating with hypericin. After incubation, the photosensitizer permeation was examined quantitatively in cryostat sections of the bladders, using fluorescence microscopy and image analysis.

RESULTS

Disrupting or neutralising the GAG layer in the bladder had no influence on the permeation of hypericin. Pre-treatment of the bladder with chondroitinase, DDM or SDS resulted in a significantly lower accumulation of hypericin, whereas neutralising the GAG layer in rats with protamine had no significant effect on the biodistribution of hypericin.

CONCLUSION

The GAG matrix causes no obstacle to the permeation of hypericin in the urothelium of the bladder, and modification of this GAG layer cannot explain the enhanced accumulation of hypericin in superficial bladder tumours.

Uroplakin II as a promising marker for molecular diagnosis of nodal metastases from bladder cancer: comparison with cytokeratin 20

PURPOSE

Current methods used to determine pathological examination of the lymphatics after radical cystectomy are tedious and costly. We performed a systemic study of uroplakin II (UP II) and cytokeratin 20 (CK 20) expression in pelvic lymph nodes on multiple sides in patients with bladder cancer.

MATERIALS AND METHODS

A total of 82 pelvic lymph node and 19 bladder tumor samples were obtained from 21 patients with bladder cancer by radical cystectomy with pelvic lymphadenectomy for reverse transcriptase-polymerase chain reaction assay.

RESULTS

Of the 19 bladder tumor tissue specimens 19 (100%) and 13 (68.4%) were positive for UP II and CK 20 mRNA expression, respectively. UP II mRNA was detected in 15 of 16 pelvic lymph node samples (93.8%) with pathologically proven metastases, whereas 9 (56.6%) were positive for CK 20 mRNA. The reverse transcriptase-polymerase chain reaction assay for UP II was statistically more sensitive than that for CK 20 in detecting not only primary tumors, but also metastatic pelvic lymph nodes (p = 0.0179 and 0.0373, respectively). Of 66 pelvic lymph node samples without metastasis UP II was detected in 6 (10%), while CK 20 was not. In addition, UP II and CK 20 mRNA could be detected in at least 50 and 500 bladder cancer HT1197 cells, respectively.

CONCLUSIONS

These results indicate that UP II might be a more useful marker than CK 20 for detecting micrometastases of bladder cancer in the pelvic lymph nodes, although a greater number of patients and longer followup are needed to come to a definitive conclusion.

Prospective evaluation of the prognostic relevance of molecular staging for urothelial carcinoma

BACKGROUND

Nearly 50% of urothelial carcinoma patients with lymph node-negative invasive cancers recur after radical surgery. In many cases, occult local or lymph node disease may be present but undetectable by current approaches. Reverse-transcriptase polymerase chain reaction (RT-PCR)-detectable mRNA of Uroplakin II (UPII), a urothelial-specific gene mRNA, was evaluated in perivesical and lymph node samples removed at radical surgery as a predictor of clinical recurrence.

METHODS

From November 1999 to August 2002, 46 patients with cTa-T4N0M0 urothelial bladder cancer enrolled in a prospective clinical trial and underwent radical cystectomy and pelvic lymphadenectomy. RT-PCR for UPII was performed on biopsies of the external surface of the bladder specimen and lymph nodes. Results were compared with conventional pathology. Patients were followed every 6 months for tumor recurrence.

RESULTS

Pathologically node-negative patients had a UPII RT-PCR perivesical positivity of 27% and a lymph node positivity rate of 33%. All 22 UPII RT-PCR node-negative patients were pathologically node-negative and all 13 with pathologically positive nodes had positive UPII RT-PCR lymph node signals. In all, 46% of UPII RT-PCR lymph node-positive patients were pathologically node-negative and 5% of pathologically node-negative/UPII RT-PCR node-negative patients had disease recurrence, whereas 91% of pathologically node-negative/UPII RT-PCR node-positive patients (P < .001) recurred. UPII RT-PCR node positivity was a significant predictor of tumor recurrence in multivariate analysis

CONCLUSIONS

Molecular determination of lymph node metastases by UPII RT-PCR node positivity apparently identifies patients with a poor prognosis and may be more predictive of disease recurrence than conventional pathologic analysis.

Urothelial umbrella cells of human ureter are heterogeneous with respect to their uroplakin composition: different degrees of urothelial maturity in ureter and bladder?

Urothelial umbrella cells are characterized by apical, rigid membrane plaques, which contain four major uroplakin proteins (UP Ia, Ib, II and III) forming UPIa/UPII and UPIb/UPIII pairs. These integral membrane proteins are thought to play an important role in maintaining the physical integrity and the permeability barrier function of the urothelium. We asked whether the four uroplakins always coexpress in the entire human lower urinary tract. We stained immunohistochemically (ABC-peroxidase method) paraffin sections of normal human ureter (n = 18) and urinary bladder (n = 10) using rabbit antibodies against UPIa, UPIb, UPII and UPIII; a recently raised mouse monoclonal antibody (MAb), AU1, and two new MAbs, AU2 and AU3, all against UPIII; and mouse MAbs against umbrella cell-associated cytokeratins CK18 and CK20. Immunoblotting showed that AU1, AU2 and AU3 antibodies all recognized the N-terminal extracellular domain of bovine UPIII. By immunohistochemistry, we found that in 15/18 cases of human ureter, but in only 2/10 cases of bladder, groups of normal-looking, CK18-positive umbrella cells lacked both UPIII and UPIb immunostaining. The UPIb/UPIII-negative cells showed either normal or reduced amounts of UPIa and UPII staining. These data were confirmed by double immunofluorescence microscopy. The distribution of the UPIb/UPIII-negative umbrella cells was not correlated with localized urothelial proliferation (Ki-67 staining) or with the distribution pattern of CK20. Similar heterogeneities were observed in bovine but not in mouse ureter. We provide the first evidence that urothelial umbrella cells are heterogeneous as some normal-looking umbrella cells can possess only one, instead of two, uroplakin pairs. This heterogeneity seems more prominent in the urothelium of human ureter than that of bladder. This finding may indicate that ureter urothelium is intrinsically different from bladder urothelium. Alternatively, a single lineage of urothelium may exhibit different phenotypes resulting from extrinsic modulations due to distinct mesenchymal influence and different degrees of pressure and stretch in bladder versus ureter. Additional studies are needed to distinguish these two possibilities and to elucidate the physiological and pathological significance of the observed urothelial and uroplakin heterogeneity.

Transcriptional control of the human urothelial-specific gene, uroplakin Ia

The transcriptional control elements of tissue-specific genes may be exploited in the design of therapeutic constructs for use in human gene therapy. The uroplakins are a family of four proteins which form the asymmetric unit membrane of the urothelium. We have cloned the human uroplakin Ia gene and defined its genomic structure and transcriptional start site. Using quantitative RT-PCR in an extended panel of normal tissues, we have demonstrated highly urothelial-specific expression of this gene. A Dual-Luciferase assay was used to assess the transcriptional activity of a variety of promoter fragments of the human uroplakin Ia gene. A highly specific promoter fragment (consisting of 2147 bp of 5'-flanking sequence, intron 1 and the 5' UTR) was identified which regulated urothelial-specific expression in vitro. The human uroplakin Ia promoter identified has potential use in future gene therapy strategies to restrict transgene expression to the urothelium.

Detection of Micrometastases in Pelvic Lymph Nodes in Patients Undergoing Radical Cystectomy for Focally Invasive Bladder Cancer by Real-time Reverse Transcriptase-PCR for Cytokeratin 19 and Uroplakin II

PURPOSE

The objective of this study was to clarify the significance of micrometastases in pelvic lymph nodes in patients who underwent radical cystectomy for bladder cancer.

EXPERIMENTAL DESIGN

We included 40 patients with locally invasive bladder cancer who underwent radical cystectomy and pelvic lymphadenectomy. Expression of cytokeratin 19 (CK19), uroplakin II (UP II), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in 760 lymph nodes were assessed by a fully quantitative real-time reverse transcription-PCR (RT-PCR) assay. The quantification value of CK19 or UP II mRNA was described as each value relative to GAPDH mRNA. In this study, we regarded specimen in which either CK19 or UP II mRNA was positive as "presence of micrometastasis."

RESULTS

Routine pathologic examinations detected tumor cells in 29 lymph nodes from six patients. Real-time RT-PCR identified positive expression of CK19 and UP II mRNAs in 49 lymph nodes from 10 patients and 98 lymph nodes from 16 patients, respectively. Of 633 lymph nodes from 34 patients with no pathologic evidence of nodal involvement, 13 nodes from five patients and 58 nodes from 10 patients were diagnosed as positive for CK19 and UP II mRNAs expression, respectively, by real-time RT-PCR. Presence of micrometastases was significantly associated with other conventional prognostic variables, including pathologic stage and microvascular invasion. Disease recurrence was occurred in eight patients, among whom four patients were negative for lymph node metastasis by routine pathologic examination and diagnosed as having micrometastasis by real-time RT-PCR assay. Furthermore, cause-specific survival rate in patients without micrometastasis was significantly higher than that in those with micrometastasis, irrespective of the presence of pathologic-positive nodes.

CONCLUSIONS

Approximately 30% of locally invasive bladder cancer shed cancer cells to pelvic lymph nodes, and disease recurrence after radical cystectomy could be explained, at least in part, by micrometastases in pelvic lymph nodes.

The management of lymph node metastasis from bladder cancer

AIM

The presence of pelvic lymph node metastasis from bladder cancer has traditionally been associated with a very poor prognosis. The aim of this paper is to review the literature with regard to the management of patients with nodal disease, particularly gross nodal metastasis and suggest a strategy for management of these patients.

METHODS

We performed a literature search in the PubMed database and the reference lists of relevant papers describing the management of locally advanced bladder cancer.

FINDINGS

There are no randomised studies relating specifically to the management of nodal metastasis in bladder cancer. It is clear however that a significant number of patients with micrometastatic nodal disease may be cured. Few studies exist which address the management of patients with gross nodal disease and consist of series from a limited number of institutions. In patients with gross nodal disease detected pre-operatively or at the time of surgery, a multimodality approach consisting of surgery, chemotherapy and possibly radiotherapy seems appropriate. The prognosis of such patients relates to the pathological stage of the primary tumour and the degree of lymph node involvement. In addition a good response to neoadjuvant chemotherapy may identify patients who are likely to survive longer.

CONCLUSIONS

The prognosis for patients with gross nodal disease from bladder cancer is poor although cure may be possible in a small number of patients. In such cases a multimodality approach is appropriate and management decisions should be made on an individual patient basis.

Detection and isolation of circulating tumor cells in urologic cancers: a review

The American Cancer Society has estimated that in 2003, there will be approximately 239,600 new cases of urologic cancer diagnosed and 54,600 urologic cancer-related deaths in the United States. To date, the majority of research and therapy design have focused on the microenvironment of the primary tumor site, as well as the microenvironment of the metastatic or secondary (target) tumor site. Little attention has been placed on the interactions of the circulating tumor cells and the microenvironment of the circulation (i.e., the third microenvironment). The purpose of this review is to present the methods for the detection and isolation of circulating tumor cells and to discuss the importance of circulating tumor cells in the biology and treatment of urologic cancers.

Cloning of human uroplakin II gene from Chinese transitional cell carcinoma of bladder and construction of its eukaryotic expression vector

To clone Uroplakin Ii gene from Chinese transitional cell carcinoma (TCC) of bladder and construct its eukaryotic expression vector, the molecular cloning method was used to extract total RNA from a GIII / T3N0M0 tissue sample of the bladder TCC patients. The primers were designed by Primer 5.0 software. Full length cDNA of Uroplakin II gene was amplified by reverse transcription polymerase chain reaction (RT-PCR), assayed by nucleic acid sequencing and then inserted between Xba I and Hind III restrictive sites of eukaryotic expression vector pcDNA3. 0. The recombinant was assayed by restricted enzyme digestion. Under the induction of Lipofectamine 2000, the recombinant was transfected into Uroplakin II negative bladder cancer cell line EJ. Cellular expression levels of Uroplakin II were detected by RT-PCR. The nucleic acid sequencing results indicated that Chinese Uroplakin II cDNA (555 bp) was successfully cloned. The BLAST analysis demonstrated that the cloned sequence is 100% homologous with sequences reported overseas. The GenBank accession number AY455312 was also registered. The results of restricted enzyme digestion indicated that eukaryotic vector pcDNA-UP II for Uroplakin II was successfully constructed. After being transferred with pcDNA-UP II for 72 h, cellular Uroplakin II mRNA levels were significantly improved (P < 0.01). It is concluded that human Uroplakin II gene was successfully cloned from Chinese TCC tissues, which provided a basis for further exploration of the roles of Uroplakin II gene in TCC biological behaviors and potential strategies for targeted biological therapy of TCC.

Cloning and analysis of human UroplakinII promoter and its application for gene therapy in bladder cancer

The differential expression of the desired gene product in the target tissue is central for gene therapy. One approach is to use a tissue-specific promoter to drive therapeutic gene expression. UroplakinII (UPII) is a urothelium-specific membrane protein. To investigate the feasibility of targeting gene therapy for bladder cancer, a DNA fragment of 2542-bp upstream of the UPII gene was amplified by PCR and linked to a promoterless firefly luciferase reporter gene. The transient transfection showed that the DNA fragment resulted in preferential expression in bladder carcinoma cells, with negligible expression in nonurothelium cells. Furthermore, the DNA segment located between -2545 and -1608 decided the tissue-specificity of the UPII promoter, the segment located between -328 and -4 being the core promoter of UPII. We generated two recombinant adenoviruses under the control of the UPII promoter: Ad-hUPII-GFP, carrying green fluorescence protein (GFP), and Ad-hUPII-TNF, carrying the tumor necrosis factor alpha (TNFalpha). ELISA revealed that the secretion of TNFalpha by Ad-hUPII-TNF-infected bladder cancer cells was significantly higher than Ad-hUPII-TNF-infected nonurothelium cells. The conditioned medium from Ad-hUPII-TNF-infected bladder cancer cells apparently inhibited the proliferation of L929 cells, a TNFalpha-sensitive cell line, comparing to Ad-hUPII-TNF-infected nonurothelium cells. Intravesical inoculation with Ad-hUPII-TNF inhibited tumor growth in the orthotopic human bladder cancer model. The sustained high level of TNFalpha in urine was identified with ELISA. Taken together, these data suggest that most of the cis elements that confer the bladder-specificity and differentiation-dependent expression of the human UPII gene reside in the 2542-bp sequence, and TNFalpha driven by the human UPII (hUPII) promoter is effective in the specific inhibition of bladder cancer growth both in vivo and in vitro. These results may yield a new therapeutic approach for bladder cancer and provide information on the molecular regulation of urothelial growth, differentiation, and disease.

Detection of circulating MUC7-positive cells by reverse transcription-polymerase chain reaction in bladder cancer patients

BACKGROUND

To determine whether MUC7 gene expression can be used as a bladder cancer marker in peripheral blood.

METHODS

Nested reverse transcription-polymerase chain reaction (RT-PCR) was performed on four types of bladder cancer cell lines (RT4, T24, EJ-1 and TCC) and the peripheral blood of 38 (31 superficial disease and seven invasive disease) bladder cancer patients and 18 subjects with urinary tract infections or other non-malignant conditions to determine the expression of MUC7.

RESULTS

No MUC7 gene expression was detected in control subjects. MUC7-positive cells were detected in all bladder cancer cell lines and in 18 of 38 (47.4%) peripheral blood samples of bladder cancer patients. Based on the tumor stage, MUC7 was detected in 11 of 29 (37.9%) patients with superficial disease (Ta and T1) and in seven of nine (77.7%) invasive disease patients (>/=T2). There was a significant difference between superficial and invasive disease (P = 0.042). Based on tumor grade, we could not detect MUC7 in five patients with grade 1, in five of 15 patients (33.3%) with grade 2 and in 13 of 18 patients (72.2%) with grade 3. There was a significant difference between grades 1 and 3 (P = 0.007) and grades 2 and 3 (P = 0.025).

CONCLUSIONS

These results suggest that MUC7 is a highly specific marker for bladder cancer and may be a useful method for the molecular staging and management of bladder cancer.

VALUE OF REVERSE TRANSCRIPTION POLYMERASE CHAIN ASSAY IN PERIPHERAL BLOOD OF PATIENTS WITH UROTHELIAL CANCER

PURPOSE

The nested reverse transcription polymerase chain reaction (RT-PCR) method was used to determine expression of uroplakin II (UP II) or cytokeratin 20 (CK-20) in cells separated from the peripheral blood of patients with urothelial cancer. We examine whether UP II or CK-20 expression can be used as a urothelial cancer marker for urothelial cancer in cells isolated from peripheral blood.

MATERIALS AND METHODS

Peripheral blood was taken from 20 healthy volunteers without a history of urothelial cancer, from 10 patients with a negative bladder biopsy for urothelial cancer and from 108 patients with urothelial cancer. Results of a nested RT-PCR assay were compared with pathological stage and recurrence.

RESULTS

None of the peripheral blood samples from the control subjects revealed a positive polymerase chain reaction result. Among 108 patients with transitional cell carcinoma of the bladder nested RT-PCR for UP II was positive in 25 (23%) versus 31 (29%) for CK-20 (p >0.05). Nested RT-PCR for UP II was positive in 5 (8%) patients with superficial stage disease (pTa and pT1) versus 8 (11%) positive for CK-20. Nested RT-PCR for UP II was positive in 15 (58%) patients with a stage of pT2 or advanced stages versus 17 (65%) positive for CK-20. Nested RT-PCR for UP II was positive in 13 (20%) and 10 (56%) patients with grades 2 and 3, respectively, versus 17 (27%) and 12 (67%) nested RT-PCR positive for CK-20. A significant difference in the Kaplan-Meier recurrence-free actuarial curve was noted among patients with superficial stage who were positive and negative on nested RT-PCR for UP II and CK-20 in peripheral blood, respectively, but not in the invasive stage. On multivariate analysis nested RT-PCR for UP II and CK-20 in peripheral blood were independent prognostic factors in patients with superficial stage disease but not with invasive stage disease. Lung and/or liver metastasis developed in 5 (80%) of 6 patients whose results after chemotherapy (consisting of cisplatin, doxorubicin hydrochloride, vinblastine sulfate and methotrexate) for nested RT-PCR for UP II and CK-20 remained positive.

CONCLUSIONS

These results seem to indicate that UP II and CK-20 mRNA in the blood may be useful tumor markers for predicting patient survival and the extent of urothelial cancer.

Detection of circulating cancer cells expressing uroplakins and epidermal growth factor receptor in bladder cancer patients

Our purpose was to determine the clinical relevance of the detection of circulating tumor cells (CTCs) expressing urothelial and epithelial markers in bladder cancer patients. Sixty-two patients who presented to Memorial Sloan-Kettering Cancer Center between July 2000 and September 2001 were studied. Peripheral blood was tested by nested RT-PCR assay for uroplakins (UPs) Ia, Ib, II and III as well as for epidermal growth factor receptor (EGFR). We determined the sensitivity and specificity of each individual marker and the combinations of UPIa/UPII and UPIb/UPIII. The latter strategy was based on our data, which showed that UPIa and UPIb form heterodimers with UPII and UPIII, respectively. Forty patients had clinically advanced bladder cancer and 22 had no evidence of disease at the time of assay. Eight of the 22 patients recurred during the follow-up period. All 8 patients were positive at presentation for UPIa/UPII. The combination of UPIa/UPII provided the best sensitivity (75%) of detecting CTCs, with a specificity of 50%. The combination of UPIb/UPIII was the most specific (79%) but had modest sensitivity (31%). Detection of EGFR-positive cells alone and in combination with UPs was inferior to that for UPIa/UPII. Combinations of urothelial markers are superior to single urothelial or epithelial markers in detecting CTCs in bladder cancer patients. Further efforts are under way to confirm the potential predictive value of these markers in a prospectively designed study of a larger cohort of patients.

Targeting gene expression of the mouse uroplakin II promoter to human bladder cells

Differential expression of the desired gene product in the target tissue is central to the concept of gene therapy. One approach is to use a tissue-specific promoter to drive therapeutic genes. To investigate the feasibility of tissue-specific gene therapy for bladder cancer using the mouse uroplakin II (UPII) promoter and its transcriptional control, the efficacy of this promoter as well as fragments in regulating gene expression were qualitatively and quantitatively analyzed in bladder and non-bladder tissue cell lines using DNA transfection. Our results demonstrate that the mouse UPII promoter actively drives gene expression in BIU-87, a bladder cancer cell line. Little promoter activity was detected in the non-bladder tissue cell lines. Furthermore, deleting the 5' end 1.5 kb of the UPII promoter by PCR, the activity was significantly decreased but was bladder-specific. However, deleting the 3' end 143-bp of the UPII promoter, the activity was hardly detected in any tissue cell lines. The activity of the 3' end 143-bp of the UPII promoter was detected in both bladder cancer and stomach cancer cell lines. These data demonstrate that the mouse UPII promoter has a high activity in human bladder cells and a low basal activity in human non-bladder cells. This suggests that targeting the gene expression of the mouse UPII promoter could be used to treat human bladder cancer. The enhancer was contained in the region of the 1.5 kb of the 5' end of the mouse UPII promoter. The core promoter was located in the region of the 143 bp of the 3' end.

Uroplakin gene expression in normal human tissues and locally advanced bladder cancer

The uroplakins are widely regarded as urothelium-specific markers of terminal urothelial cytodifferentiation. This study investigated the expression of the four uroplakin genes, UPIa, UPIb, UPII and UPIII, in a wide range of normal human tissues to determine tissue specificity and in advanced transitional cell carcinoma (TCC) to examine gene expression in primary and metastatic disease. In the urinary tract, all four uroplakins were expressed by urothelium and UPIII was also expressed by prostatic glandular epithelium. UPIa and UPII appeared to be urothelium-specific, but UPIb was detected in several non-urothelial tissues, including the respiratory tract, where it was associated with squamous metaplasia of tracheal and bronchial epithelia. The ten cases of primary TCC and corresponding lymph node metastases demonstrated that each uroplakin gene could be expressed at the mRNA level. No single uroplakin gene was expressed in all primary tumours or metastases, but 80% of the primary tumours and 70% of the lymph node metastases expressed at least one uroplakin gene. UPIII mRNA was often expressed in the absence of UPIII protein. These results confirm that in human tissues the expression of UPIa and UPII genes is highly specific to urothelium and suggest that the tight differentiation-restricted expression of uroplakin genes in normal urothelium is lost following malignant transformation.

Uroplakin expression in the urothelial tumors of cows

Expression of uroplakins (UPs) was investigated in 20 bladder tumors from cows that had been suffering from chronic enzootic hematuria for several years. In dysplastic urothelium and papillomatous proliferations, UP expression was evident both as luminal and intercellular staining. UPs appeared to clearly define the plasma membrane of luminal cells and the borders of cells placed in deeper layers, whether or not these intermediate cells were adjacent to superficial ones. Occasionally, some intermediate cells showed a remarkable cytoplasmic immunoreactivity. The pattern of UPs in grade I tumors was characterized by an evident discontinuity of luminal staining and by the presence of numerous intermediate cells showing a diffuse intracytoplasmic positivity for UPs. In grade II tumors, there was a decrease of luminal and intermediate cells showing UP expression and an apparent increase of clusters of intermediate cells with intracytoplasmic reactivity for UPs. In grade III tumors, immunoreactivity was heterogeneously distributed and a severe loss of UP-positive luminal and intermediate cells could be seen. Focally, superficial and deeper cells showed strong membraneous immunoreactivity that marked and delimited single cells, with complete circumferential peripheral staining clearly evident. UP expression in bladder tumors of cows reported in this study is similar to the UP pattern of some urothelial tumors in humans. Although UP expression is remarkably changed in bladder carcinogenesis of cattle, the UP gene(s) remains expressed during cell transformation and tumor progression.

Uroplakin as a marker for typing metastatic transitional cell carcinoma on fine-needle aspiration specimens

BACKGROUND

Immunohistological markers specific for a single type of epithelium are rare. Recently, urothelium tissue-specific genes were cloned. The genes encoded a family of transmembrane proteins, uroplakins, that are expressed only in urothelial mucosa. Using uroplakin antibodies on paraffin-embedded tissue, a previous study demonstrated positive staining in 66% of metastatic transitional cell carcinoma (TCC) cases and negative staining in all other tumors (including breast, ovarian, lung, and gastrointestinal carcinomas) tested. The current study addresses the diagnostic value of uroplakins in conventional fine-needle aspiration (FNA) material in establishing a diagnosis of metastatic TCC.

METHODS

Representative slides from 27 FNA cases of metastatic TCC and 52 non-TCC carcinomas were collected. The avidin-biotin-peroxidase method was utilized, using polyclonal antiuroplakin as the primary antibody on 95% ethanol-fixed, Papanicoloau-stained direct smears.

RESULTS

Twenty-five of 27 metastatic TCC cases (93%) were found to stain positively for uroplakin with a superficial membrane/microluminal staining pattern. A few cells with diffuse membranous staining also were noted in 48% of the positive metastatic TCC cases. The superficial membrane/microluminal staining pattern was not observed in any of the non-TCC carcinomas. However, approximately 6% of these cases (3 of 52 cases) did show rare tumor cells with diffuse membranous staining.

CONCLUSIONS

The application of uroplakin antibodies to 95% ethanol-fixed FNA direct smears has improved the sensitivity of the antibody for metastatic TCC while maintaining a specificity comparable to that of paraffin-embedded tissue. The authors believe that these antibodies have diagnostic potential in cytopathology in the evaluation of metastatic TCC.

Molecular detection and characterization of circulating tumor cells and micrometastases in prostatic, urothelial, and renal cell carcinomas

The detection and molecular characterization of circulating tumor cells (CTCs) and micrometastases in urinary tract and prostatic tumors may have important prognostic and therapeutic implications. In the last decade, numerous groups have attempted the detection of occult tumor cells in renal, prostatic, and urothelial carcinomas using the highly sensitive reverse-transcriptase polymerase chain reaction (RT-PCR). In prostatic carcinoma (PC), tissue-specific transcripts were detected with high specificity in the blood of patients with localized and advanced disease. PCR assays for PC detection were shown to be strong predictors of poorer outcome in some reports, while a lack of prognostic significance was found in other studies. There was a vast difference in the PCR positivity rates between various groups studying PC. This discrepancy could be due to variations in PCR methodology. In urothelial and renal cell carcinoma, the amount of research on the subject is still too limited. Currently, these assays for occult tumor cells are promising but are not yet ready to use in PC and urinary tract tumors. Because of the many limitations of PCR (e.g., false positives), many groups are developing new approaches for the detection of occult tumor cells. The most attractive technique involves immunomagnetic isolation of intact CTC and micrometastases prior to downstream analysis. The tumor-rich magnetic fraction can be subjected to RT-PCR, immunocytochemistry, and in situ hybridization. This will lead to better quantification and molecular characterization of these tumor cells.

Bladder cancer

There is a need for the development of reliable tumor markers in bladder cancer. A number of studies this past year focused on the evaluation of urinary markers that hold promise as noninvasive adjuncts to traditional diagnostic or surveillance techniques, principally urinary cytology and cystoscopy. Tests for bladder tumor antigen, NMP22, and fibrin degradation products, as well as the Immunocyt test, are commercially available. Other urinary marker tests discussed in this review include telomerase, cytokeratins, and vascular endothelial growth factor. Although these tests in many instances have improved sensitivity in detecting bladder cancer compared with urinary cytology, none have become widely accepted in routine clinical practice. Nonetheless, with further refinement and prospective validation in multicenter trials, markers such as these may provide information that would permit tailoring on an individual basis the type of as well as interval of surveillance examinations. Furthermore, they may also provide information allowing the appropriate selection of therapy based on predicted response. In addition to urinary markers, intense research efforts have also focused on developing clinically useful molecular prognostic markers. A number of cell-cycle regulatory proteins, including p53 and p21, have received much attention in this regard. Emerging data suggests that it may soon be possible to determine the molecular phenotype of both superficial and invasive bladder cancers, thereby providing information regarding tumor behavior on an individual basis. As with urinary markers, however, no molecular markers have been incorporated as yet into day-to-day patient care. Assurances of reproducibility, standardization, and prospective validation studies are urgently needed. It is only through this type of rigorous evaluation that the level of confidence sufficient to base treatment decisions on marker status will be attained.