Molecular detection of primary bladder cancer by microsatellite analysis

Microsatellite Instability in Urine: Breakthrough Method for Bladder Cancer Identification

Bladder cancer (BC) is the most common neoplasm of the urinary system and ranks tenth in global cancer incidence. Due to its high recurrence rate and the need for continuous monitoring, it is the cancer with the highest cost per patient. Cystoscopy is the traditional method for its detection and surveillance; however, this is an invasive technique, while non-invasive methods, such as cytology, have a limited sensitivity. For this reason, new non-invasive strategies have emerged, analyzing useful markers for BC detection from urine samples. The identification of tumor markers is essential for early cancer detection and treatment. Urine analysis offers a non-invasive method to identify these markers. Microsatellite instability (MSI) has been proposed as a promising marker for tumor cell detection and guided targeted therapies. Therefore, this review aims to explore the evidence supporting the identification of MSI in exfoliated bladder tumor cells (EBTCs) in the urine, emphasizing its potential as a non-invasive and clinically effective alternative for tumor identification. Furthermore, establishing clinical guidelines is crucial for standardizing its application in oncological screening and validating its clinical utility.

Results Obtained from a Pivotal Validation Trial of a Microsatellite Analysis (MSA) Assay for Bladder Cancer Detection through a Statistical Approach Using a Four-Stage Pipeline of Modern Machine Learning Techniques

Several studies have shown that microsatellite changes can be profiled in urine for the detection of bladder cancer. The use of microsatellite analysis (MSA) for bladder cancer detection requires a comprehensive analysis of as many as 15 to 20 markers, based on the amplification and interpretations of many individual MSA markers, and it can be technically challenging. Here, to develop fast, more efficient, standardized, and less costly MSA for the detection of bladder cancer, we developed three multiplex-polymerase-chain-reaction-(PCR)-based MSA assays, all of which were analyzed via a genetic analyzer. First, we selected 16 MSA markers based on 9 selected publications. Based on samples from Johns Hopkins University (the JHU sample, the first set sample), we developed an MSA based on triplet, three-tube-based multiplex PCR (a Triplet MSA assay). The discovery, validation, and translation of biomarkers for the early detection of cancer are the primary focuses of the Early Detection Research Network (EDRN), an initiative of the National Cancer Institute (NCI). A prospective study sponsored by the EDRN was undertaken to determine the efficacy of a novel set of MSA markers for the early detection of bladder cancer. This work and data analysis were performed through a collaboration between academics and industry partners. In the current study, we undertook a re-analysis of the primary data from the Compass study to enhance the predictive power of the dataset in bladder cancer diagnosis. Using a four-stage pipeline of modern machine learning techniques, including outlier removal with a nonlinear model, correcting for majority/minority class imbalance, feature engineering, and the use of a model-derived variable importance measure to select predictors, we were able to increase the utility of the original dataset to predict the occurrence of bladder cancer. The results of this analysis showed an increase in accuracy (85%), sensitivity (82%), and specificity (83%) compared to the original analysis. The re-analysis of the EDRN study results using machine learning statistical analysis proved to achieve an appropriate level of accuracy, sensitivity, and specificity to support the use of the MSA for bladder cancer detection and monitoring. This assay can be a significant addition to the tools urologists use to both detect primary bladder cancers and monitor recurrent bladder cancer.

Qualification of the Microsatellite Instability Analysis (MSA) for Bladder Cancer Detection: The Technical Challenges of Concordance Analysis

Bladder cancer (here we refer to transitional carcinoma of bladder) is a major cause of morbidity and mortality in the Western world, and recent understanding of its etiology, the molecular characteristics associated with its progression, renders bladder cancer an ideal candidate for screening. Cystoscopy is invasive and sometimes carries unwanted complications, but it is the gold standard for the detection of bladder cancer. Urine cytology, while the most commonly used test as an initial screening tool, is of limited value due to its low sensitivity, particularly for low-grade tumors. Several new "molecular assays" for the diagnosis of urothelial cancer have been developed over the last two decades. Here, we have established our new bladder cancer test based on an assay established for the Early Detection Research Network (EDRN) study. As a part of the study, a quality control CLIA/College of American Pathology (CAP) accredited laboratory, (QA Lab), University of Maryland Baltimore Biomarker Reference Laboratory (UMB-BRL), performed quality assurance analysis. Quality assurance measures included a concordance study between the testing laboratory (AIBioTech), also CLIA/CAP accredited, and the QA lab to ensure that the assay was performed and the results were analyzed in a consistent manner. Therefore, following the technical transfer and training of the microsatellite analysis assay to the UMB-BRL and prior to the initiation of analysis of the clinical samples by the testing lab, a series of qualification studies were performed. This report details the steps taken to ensure qualification of the assay and illustrates the technical challenges facing biomarker validation of this kind.

Development of Multiplex Polymerase Chain Reaction (PCR)-Based MSA Assay for Bladder Cancer Detection

Several studies have shown that microsatellite changes can be profiled in the urine to detect bladder cancer. Microsatellite analysis (MSA) of bladder cancer detection requires a comprehensive analysis of up to 15-20 markers based on amplifying and interpreting many individual MSA markers, which can be technically challenging. To develop fast, efficient, standardized, and less costly MSA to detect bladder cancer, we developed three multiplex polymerase chain reaction (PCR) based MSA assays, all of which were analyzed by a genetic analyzer. First, we selected 16 MSA markers based on nine publications. We developed MSA assays based on triplet or three-tube-based multiplex PCR (Triplet MSA assay) using samples from Johns Hopkins University (JHU Sample, first set of samples). In the second set of samples (samples from six cancer patients and fourteen healthy individuals), our Triplet Assay with 15 MSA markers correctly predicted all 6/6 cancer samples to be cancerous and 14/14 healthy samples to be healthy. Although we could improve our report with more clinical information from patient samples and an increased number of cancer patients, our overall results suggest that our Triplet MSA Assay combined with a genetic analyzer is a potentially time- and cost-effective genetic assay for bladder cancer detection and has potential use as a dependable assay in patient care.

Microsatellite Instability Analysis (MSA) for Bladder Cancer: Past History and Future Directions

Microsatellite instability (MSI), the spontaneous loss or gain of nucleotides from repetitive DNA tracts, is a diagnostic phenotype for gastrointestinal, endometrial, colorectal, and bladder cancers; yet a landscape of instability events across a wider variety of cancer types is beginning to be discovered. The epigenetic inactivation of the MLH1 gene is often associated with sporadic MSI cancers. Recent next-generation sequencing (NGS)-based analyses have comprehensively characterized MSI-positive (MSI+) cancers, and several approaches to the detection of the MSI phenotype of tumors using NGS have been developed. Bladder cancer (here we refer to transitional carcinoma of the bladder) is a major cause of morbidity and mortality in the Western world. Cystoscopy, a gold standard for the detection of bladder cancer, is invasive and sometimes carries unwanted complications, while its cost is relatively high. Urine cytology is of limited value due to its low sensitivity, particularly to low-grade tumors. Therefore, over the last two decades, several new "molecular assays" for the diagnosis of urothelial cancer have been developed. Here, we provide an update on the development of a microsatellite instability assay (MSA) and the development of MSA associated with bladder cancers, focusing on findings obtained from urine analysis from bladder cancer patients as compared with individuals without bladder cancer. In our review, based on over 18 publications with approximately 900 sample cohorts, we provide the sensitivity (87% to 90%) and specificity (94% to 98%) of MSA. We also provide a comparative analysis between MSA and other assays, as well as discussing the details of four different FDA-approved assays. We conclude that MSA is a potentially powerful test for bladder cancer detection and may improve the quality of life of bladder cancer patients.

Improvement of the Collection, Maintenance, and Analysis of Neoplastic Cells from Urine Specimens with the Use of CytoMatrix

Urine cytology is a non-invasive test used in combination with cystoscopy for screening and follow-up of urothelial carcinoma (UC). Although cytology can be used to efficiently identify high-grade UC, it has a lower accuracy for the diagnosis of low-grade UC or patients with presence of atypical urothelial cells (AUC). For these reasons, ancillary tests have been added to urine cytology in order to improve the accuracy. However, the poor abundance of neoplastic cells in most samples and the absence of a "tissue-like" structure remains a major challenge. We used a novel synthetic support called CytoMatrix which has the property of capturing and storing cells and micro-macro aggregates within its three-dimensional structure. The urine specimens were obtained from 12 patients: 6 with suspected urothelial neoplasia (low- and high-grade) and 6 with AUC or non-neoplastic samples. The first step is the urine samples preparation, through several centrifugation passages; the second step consists in absorbing cells on the CytoMatrix, and in the subsequent formalin fixation, standard processing and paraffin embedding to prepare FFPE-CytoMatrix block. In the final step, sections are consecutively cut, stained with hematoxylin-eosin (H&E), and analyzed via UroVysion FISH and immunohistochemistry (IHC). Using our simple and reliable protocol, we can improve the quality of urine specimens, allowing a better collection, maintenance, and analysis of cells, with the advantage of using ancillary tests to support cytological diagnosis and the advantage of storing cellular material in a FFPE-CytoMatrix block.

Trends in urine biomarker discovery for urothelial bladder cancer: DNA, RNA, or protein?

Urothelial bladder cancer is a complex disease displaying a landscape of heterogenous molecular subtypes, mutation profiles and clinical presentations. Diagnosis and surveillance rely on flexible cystoscopy which has high accuracy, albeit accompanied by a high-cost burden for healthcare providers and discomfort for patients. Advances in "omic" technologies and computational biology have provided insights into the molecular pathogenesis of bladder cancer and provided powerful tools to identify markers for disease detection, risk stratification, and predicting responses to therapy. To date, numerous attempts have been made to discover and validate diagnostic biomarkers that could be deployed as an adjunct to the cystoscopic diagnosis and long-term surveillance of bladder cancer. We report a comprehensive literature analysis using PubMed to assess the changing trends in investigating DNA, RNA, or proteins as diagnostic urinary biomarkers over a period of 5 decades: 1970-2020. A gradual shift has been observed in research away from protein biomarkers to nucleic acids including different classes of RNA, and DNA methylation and mutation markers. Until 2000, publications involving protein biomarker discovery constituted 87% of the total number of research articles with DNA comprising 6% and RNA 7%. Since 2000 the proportion of protein biomarker articles has fallen to 40%, and DNA and RNA studies increased to 32% and 28%, respectively. Clearly research focus, perhaps driven by technological innovation, has shifted from proteins to nucleic acids. We optimistically hypothesise that, following thorough validation, a clinically useful detection test for bladder cancer based on a panel of DNA or RNA markers could become reality within 5-10 years.

No evidence of EMAST in whole genome sequencing data from 248 colorectal cancers

Microsatellite instability (MSI) is caused by defective DNA mismatch repair (MMR), and manifests as accumulation of small insertions and deletions (indels) in short tandem repeats of the genome. Another form of repeat instability, elevated microsatellite alterations at selected tetranucleotide repeats (EMAST), has been suggested to occur in 50% to 60% of colorectal cancer (CRC), of which approximately one quarter are accounted for by MSI. Unlike for MSI, the criteria for defining EMAST is not consensual. EMAST CRCs have been suggested to form a distinct subset of CRCs that has been linked to a higher tumor stage, chronic inflammation, and poor prognosis. EMAST CRCs not exhibiting MSI have been proposed to show instability of di- and trinucleotide repeats in addition to tetranucleotide repeats, but lack instability of mononucleotide repeats. However, previous studies on EMAST have been based on targeted analysis of small sets of marker repeats, often in relatively few samples. To gain insight into tetranucleotide instability on a genome-wide level, we utilized whole genome sequencing data from 227 microsatellite stable (MSS) CRCs, 18 MSI CRCs, 3 POLE-mutated CRCs, and their corresponding normal samples. As expected, we observed tetranucleotide instability in all MSI CRCs, accompanied by instability of mono-, di-, and trinucleotide repeats. Among MSS CRCs, some tumors displayed more microsatellite mutations than others as a continuum, and no distinct subset of tumors with the previously proposed molecular characters of EMAST could be observed. Our results suggest that tetranucleotide repeat mutations in non-MSI CRCs represent stochastic mutation events rather than define a distinct CRC subclass.

Diagnostic value of a comprehensive, urothelial carcinoma-specific next-generation sequencing panel in urine cytology and bladder tumor specimens

BACKGROUND

Urine cytology can reliably diagnose high-grade urothelial carcinoma (HGUC) but not low-grade urothelial carcinoma (LGUC), and a more sensitive test is needed. Previously, a pilot study highlighted the possible diagnostic utility of next-generation sequencing (NGS) in identifying both LGUC and HGUC in urine cytology specimens.

METHODS

Twenty-eight urine ThinPrep cytology specimens and preceding or subsequent bladder tumor biopsy/resection specimens obtained within 3 months were included in the study (LGUC, n = 15; HGUC, n = 13). A customized, bladder-specific NGS panel was performed; it covered 69 frequently mutated or altered genes in urothelial carcinoma (UC) that were reported by The Cancer Genome Atlas and the Catalogue of Somatic Mutations in Cancer.

RESULTS

The sequencing results were compared between the urine cytology specimens and the corresponding bladder tumor biopsies/resections. TP53 was the most frequently identified mutation in HGUC cases (11 of 13 [85%]). PIK3CA and KDM6A were the most frequently identified mutations in LGUC: they occurred in 7 of 15 cases (47%) and in 6 of 15 cases (40%), respectively. Additional frequent mutations identified in the panel included ARID1A (n = 5), EP300 (n = 4), LRP1B (n = 3), ERBB2 (n = 2), STAG2 (n = 2), FGFR3 (n = 3), MLL (n = 2), MLL3 (n = 2), CREBBP1 (n = 1), RB1 (n = 1), and FAT4 (n = 1). Overall, the concordance between the cytology and surgical specimens was 75%. The sensitivity and specificity for identifying mutations in urine cytology specimens were 84% and 100%, respectively.

CONCLUSIONS

A bladder-specific NGS panel increases the sensitivity and specificity of urine cytology's diagnostic utility in both low- and high-grade tumors and may serve as a noninvasive surveillance method in the follow-up of patients with UC harboring known mutations.

Adding Rigor to Biomarker Evaluations-EDRN Experience

The cancer early-detection biomarker field was, compared with the therapeutic arena, in its infancy when the Early Detection Research Network (EDRN) was initiated in 2000. The EDRN has played a crucial role in changing the culture and the ways people conduct biomarker studies. The EDRN proposed biomarker developmental guidelines and biomarker pivotal trial study design standards, created biomarker reference sets and functioned as an unbiased broker for the field, implemented the most rigorous blinding policy in the biomarker field, developed an array of statistical and computational tools for early-detection biomarker evaluations, and developed a multidisciplinary team-science approach. We reviewed these contributions made by the EDRN and their impacts on maturing the field. Future challenges and opportunities in cancer early-detection biomarker translational research are discussed, particularly in strengthening biomarker discovery pipeline and conducting more efficient biomarker validation studies.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

The Diagnostic and Prognostic Performance of Urinary FGFR3 Mutation Analysis in Bladder Cancer Surveillance: A Prospective Multicenter Study

OBJECTIVE

To assess the diagnostic and prognostic performance of a noninvasive FGFR3 mutation analysis. After transurethral resection (TUR) of noninvasive bladder transitional cell carcinoma (B-TCC), recurrence occurs in 70% of patients, thus justifying cystoscopic surveillance.

MATERIALS AND METHODS

A prospective multicenter study was carried out with a 2-year follow-up of patients with superficial B-TCC. Urine samples were collected before TUR and then before each cystoscopy during follow-up. Screening for the most prevalent FGFR3 mutations was done using urinary cells. The prognostic significance of an FGFR3 mutation at the time of the initial diagnosis was determined. The performance of the test in diagnosing and/or predicting recurrence during follow-up was assessed by calculating sensitivity and specificity.

RESULTS

Of 191 patients studied, 74 (39%) had a positive analysis before TUR (FGFR3 mutation group). The presence of an FGFR3 mutation at the time of diagnosis was associated with a shorter time to recurrence (P = .02). During follow-up, 68 patients from the FGFR3 mutation group were evaluated. FGFR3 mutation analysis showed a sensitivity of 0.73 and a specificity of 0.87 when compared with the results of cystoscopy. A positive urine test was predictive of recurrence either at the time of the positive result or later during the 2-year follow-up, with a sensitivity of 0.70 and a specificity of 0.87.

CONCLUSION

Among patients with an FGFR3 mutation in the initial tumor, a noninvasive urine test during follow-up can be valuable in diagnosing or predicting subsequent recurrence.

EMAST is a Form of Microsatellite Instability That is Initiated by Inflammation and Modulates Colorectal Cancer Progression

DNA mismatch repair (MMR) function is critical for correcting errors coincident with polymerase-driven DNA replication, and its proteins are frequent targets for inactivation (germline or somatic), generating a hypermutable tumor that drives cancer progression. The biomarker for defective DNA MMR is microsatellite instability-high (MSI-H), observed in ~15% of colorectal cancers, and defined by mono- and dinucleotide microsatellite frameshift mutations. MSI-H is highly correlated with loss of MMR protein expression, is commonly diploid, is often located in the right side of the colon, prognosticates good patient outcome, and predicts poor efficacy with 5-fluorouracil treatment. Elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) is another form of MSI at tetranucleotide repeats that has been observed in multiple cancers, but its etiology and clinical relevance to patient care has only been recently illuminated. Specifically, EMAST is an acquired somatic defect observed in up to 60% of colorectal cancers and caused by unique dysfunction of the DNA MMR protein MSH3 (and its DNA MMR complex MutSβ, a heterodimer of MSH2-MSH3), and in particular a loss-of-function phenotype due to a reversible shift from its normal nuclear location into the cytosol in response to oxidative stress and the pro-inflammatory cytokine interleukin-6. Tumor hypoxia may also be a contributor. Patients with EMAST colorectal cancers show diminished prognosis compared to patients without the presence of EMAST in their cancer. In addition to defective DNA MMR recognized by tetranucleotide (and di- and tri-nucleotide) frameshifts, loss of MSH3 also contributes to homologous recombination-mediated repair of DNA double stranded breaks, indicating the MSH3 dysfunction is a complex defect for cancer cells that generates not only EMAST but also may contribute to chromosomal instability and aneuploidy. Areas for future investigation for this most common DNA MMR defect among colorectal cancers include relationships between EMAST and chemotherapy response, patient outcome with aneuploid changes in colorectal cancers, target gene mutation analysis, and mechanisms related to inflammation-induced compartmentalization and inactivation for MSH3.

Detection of specific chromosomal aberrations in urine using BCA-1 (oligo-CGH-array) enhances diagnostic sensitivity and predicts the aggressiveness of non-muscle-invasive bladder transitional cell carcinoma

Introduction

Bladder carcinoma (B-TCC) is the fifth most prevalent carcinoma in the United States (US) or Europe. In addition, B-TCC is the most expensive carcinoma per patient between diagnosis and death, because of its 50–80 % recurrence rate. B-TCC is an optimal carcinoma for which to detect DNA alterations in urine, which is easily obtainable. Chromosomal aberrations in tumors have been closely related to the carcinogenesis process.

Material and Methods

We developed a highly specific and sensitive oligo-CGH-array for the diagnosis and follow-up of B-TCC, based on the detection of chromosomal aberrations in urine samples. One hundred and sixty-four urine samples were analyzed. The qualitative results, including chromosomal aberrations, were obtained. Quantitative results are expressed as a percentage of chromosomal alterations on the autosomes.

Results

From the urine samples, we were able to differentiate B-TCC from non-malignant conditions with an accuracy of 100 % for patients without history of B-TCC. For follow-up of B-TCC in clinical practice, at least a deletion (8p; 9p; 9q) or a cut-off of >2 % of chromosomal imbalance was considered as a positive test. According to our criteria, 100 % of high-grade tumors were diagnosed, and the sensitivity to predict positive cystoscopy was 95 % (specificity 73 %). A cut-off >9 % was a strong signature of high-grade TCC (odds ratio 53 CI 95 % 7–417; p = 0.0002).

Conclusion

We developed a sensitive clinical tool for the detection of B-TCC using DNA extracted from patient urine. This tool is also able to identify low-grade B-TCC and identify high-risk patients harboring a high-grade disease.

Follow-up procedures for non-muscle-invasive bladder cancer: an update

Bladder carcinoma is the most common malignancy of the urinary tract. Approximately 75-85% of patients present with a disease that is confined to the mucosa (stage Ta, carcinoma in situ) or submucosa (stage T1). The stratification of patients to low-, intermediate- and high-risk groups represents the cornerstone for the indication of adjuvant and follow-up treatment. Owing to the high recurrence rate of bladder tumors, a surveillance protocol is recommended to all patients. Currently, the combination of cystoscopy, imaging and urinary cytology represent the follow-up. A systematic review of the recent English literature on follow-up procedures of non-muscle-invasive bladder cancer is performed. The authors review the existing follow-up procedures, with a focus on novel molecular-targeted approaches. At the present time, the additional use and utility of urine-based molecular markers in the follow-up of patients remains unclear and we have to rely on cystoscopic evaluation adapted to risk group classification.

Tumor-specific microsatellite instability: do distinct mechanisms underlie the MSI-L and EMAST phenotypes?

Microsatellite DNA sequences display allele length alterations or microsatellite instability (MSI) in tumor tissues, and MSI is used diagnostically for tumor detection and classification. We discuss the known types of tumor-specific MSI patterns and the relevant mechanisms underlying each pattern. Mutation rates of individual microsatellites vary greatly, and the intrinsic DNA features of motif size, sequence, and length contribute to this variation. MSI is used for detecting mismatch repair (MMR)-deficient tumors, which display an MSI-high phenotype due to genome-wide microsatellite destabilization. Because several pathways maintain microsatellite stability, tumors that have undergone other events associated with moderate genome instability may display diagnostic MSI only at specific di- or tetranucleotide markers. We summarize evidence for such alternative MSI forms (A-MSI) in sporadic cancers, also referred to as MSI-low and EMAST. While the existence of A-MSI is not disputed, there is disagreement about the origin and pathologic significance of this phenomenon. Although ambiguities due to PCR methods may be a source, evidence exists for other mechanisms to explain tumor-specific A-MSI. Some portion of A-MSI tumors may result from random mutational events arising during neoplastic cell evolution. However, this mechanism fails to explain the specificity of A-MSI for di- and tetranucleotide instability. We present evidence supporting the alternative argument that some A-MSI tumors arise by a distinct genetic pathway, and give examples of DNA metabolic pathways that, when altered, may be responsible for instability at specific microsatellite motifs. Finally, we suggest that A-MSI in tumors could be molecular signatures of environmental influences and DNA damage. Importantly, A-MSI occurs in several pre-neoplastic inflammatory states, including inflammatory bowel diseases, consistent with a role of oxidative stress in A-MSI. Understanding the biochemical basis of A-MSI tumor phenotypes will advance the development of new diagnostic tools and positively impact the clinical management of individual cancers.

Germline prognostic markers for urinary bladder cancer: obstacles and opportunities

Urinary bladder cancer is a heterogeneous disease with diverse genetic and environmental risk factors that can influence disease risk or clinical course for recurrence, progression, and survival. Therefore, identification of these factors is paramount for disease prevention and optimal clinical management of bladder cancer patients. Of particular interest is the need to identify molecular biomarkers that can give accurate assessment of tumor biological potential and to predict treatment response. Recent advances in molecular biology, cytogenetic, and genomic research have spurred discovery efforts for novel genetic, epigenetic, and proteomic biomarkers that are prognostic for cancer. This review focuses on some of the important germ line polymorphisms found to be correlated with clinical outcomes in bladder cancer. So far, most of the identified candidate loci were based on prior knowledge of pathogenesis and had not been validated for clinical applications. The future challenges are to analyze the wealth of information from whole-genome studies, to understand the underlying biological mechanisms of these associations, the network of gene-gene and gene-environment interactions, and to apply these markers for the identification of high-risk population for targeted, personalized therapy.

Telomerase activity Simplification of assay and detection in bladder tumor and urinary exfoliated cells

Detection of telomerase activity can differentiate malignant from benign cells. However, the original telomeric repeat amplification protocol (TRAP) methods had a number of limitations including a radioisotope labeling [α(32)P] dCTP [α(32)P] dGTP system. We developed digoxigenin labeled CX primer to detect telomerase activity without using radioisotope and attempted to detect telomerase activity of bladder tumor and exfoliated cells in bladder cancer patients. Telomerase activity was detected in 5 (71%) of 7 patients diagnosed with grade 1, 31 (97%) of 32 grade 2, and 11 (100%) of 11 grade 3 bladder tumors. In urinary exfoliated cells, 32 (82%) of 39 grades 1 or 2 bladder tumors were positive for telomerase activity but 20 (51%) of 39 were positive for urinary cytology (P < 0.01). Ten (91%) of 11 of grade 3 tumors were positive for telomerase activity and 11 (100%) of 11 were positive urinary cytology. Three of 100 noncancerous patients were positive for telomerase activity. Sensitivity, specificity, and positive predictive value of telomerase activity assay in urinary exfoliated cells were 84%, 97%, and 93%, respectively. Telomerase activity may be a useful diagnostic marker to detect the existence of immortal cancer cells in the urine.

Markers of bladder cancer State of the art

Biomarkers are increasingly being applied to the clinical management of patients with bladder cancer. The biomarkers in current clinical use focus on bladder cancer detection. Biomarkers for prognosis and as intermediate endpoints for chemoprevention are being evaluated in clinical trials. This review provides an overview of the performance characteristics of current clinical markers and other markers that are currently under evaluation.

Selection of microsatellite markers for bladder cancer diagnosis without the need for corresponding blood

Microsatellite markers are used for loss-of-heterozygosity, allelic imbalance and clonality analyses in cancers. Usually, tumor DNA is compared to corresponding normal DNA. However, normal DNA is not always available and can display aberrant allele ratios due to copy number variations in the genome. Moreover, stutter peaks may complicate the analysis. To use microsatellite markers for diagnosis of recurrent bladder cancer, we aimed to select markers without stutter peaks and a constant ratio between alleles, thereby avoiding the need for a control DNA sample. We investigated 49 microsatellite markers with tri- and tetranucleotide repeats in regions commonly lost in bladder cancer. Based on analysis of 50 blood DNAs the 12 best performing markers were selected with few stutter peaks and a constant ratio between peaks heights. Per marker upper and lower cut off values for allele ratios were determined. LOH of the markers was observed in 59/104 tumor DNAs. We then determined the sensitivity of the marker panel for detection of recurrent bladder cancer by assaying 102 urine samples of these patients. Sensitivity was 63% when patients were stratified for LOH in their primary tumors. We demonstrate that up-front selection of microsatellite markers obliterates the need for a corresponding blood sample. For diagnosis of bladder cancer recurrences in urine this significantly reduces costs. Moreover, this approach facilitates retrospective analysis of archival tumor samples for allelic imbalance.

Detection of loss of heterozygosity in patients with urinary bladder carcinoma: neoplastic tissue vs. urine sediment cells

Introduction

Loss of heterozygosity (LOH) is frequently observed in urinary bladder neoplasms. In the reported study, an attempt was undertaken to determine the loss of heterozygosity of TP53(17p13), RB1(13q14), CDKN2A/ ARF(9p21) genes in DNA from neoplastic tissue, collected from patients with diagnosed urinary bladder carcinoma, and to compare the results with those of LOH evaluation in DNA isolated from urine sediment cells.

Material and methods

After isolation, DNA was amplified (PCR) by means of primers to five polymorphic microsatellite markers, the products being then separated on agarose gel. Following the method, a total of 125 DNA samples were obtained, isolated from neoplastic cells, together with 125 corresponding DNA samples, isolated from urine sediment cells.

Results

The loss of heterozygosity in at least one marker was identified in 39.2%. (49/125) of DNA from studied tumors and in 34.3% (43/125) of DNA samples, isolated from urine sediment cells. An analysis of LOH from the DNA, isolated from urine sediment cells, allowed for identification of 81.8% of neoplastic tumors with 99.7% specificity.

Conclusions

Our observations have demonstrated that LOH within 13q14, 17p13 and 9p21 loci is more often observed in clinically more advanced neoplasms. LOH in 17p13 locus is more frequently found in tumors at high histopathological stage, while in low-stage neoplasms, LOH is most often observed on chromosome 9. The high sensitivity (81.8%) and specificity (99.7%) of LOH studies in DNA, isolated from urine sediment cells, make this technique an advantageous, non-invasive method for detection and screening of bladder cancer.

Evaluation of microsatellite instability in urine for the diagnosis of transitional cell carcinoma of the lower urinary tract in dogs

BACKGROUND

The accumulation of frame-shift mutations in microsatellites (MS), termed microsatellite instability (MSI), is associated with certain tumors. MSI and its detection in urine samples has been used to aid in the detection of human bladder cancer.

HYPOTHESIS

Evaluation of MSI in urine is a useful assay test for diagnosis of transitional cell carcinoma (TCC) in dogs and is more specific than the commercially available, veterinary bladder tumor analyte (V-BTA) test.

ANIMALS

Seventy-three dogs: healthy controls (n=21), proteinuric (n=12), lower urinary tract disease excluding TCC (n=17), and TCC (n=23).

METHODS

Prospective observational study. Urine samples collected from each animal were evaluated for MSI and using the V-BTA. For MSI detection, 22 MS sequences were polymerase chain reaction amplified from urine and blood, subjected to capillary electrophoresis, and the MS genotypes were compared. Aberration in ≥15% of MS was considered indicative of MSI.

RESULTS

MSI was detected in 11 of 23 (48%) urine samples from dogs with TCC. MSI was also detected in 12 of 50 (24%) of the control animals, including 29, 16, and 24% of healthy, proteinuric, and lower urinary disease dogs, respectively. In this population, sensitivity and specificity of MSI analysis was 48 and 76%, respectively, compared with 83 and 64%, respectively, for the V-BTA test.

CONCLUSIONS

MS analysis as performed in this study is not useful in the diagnosis of TCC.

Developing biomarkers for improved diagnosis and treatment outcome monitoring of bladder cancer

IMPORTANCE OF THE FIELD

A non-invasive marker for the follow-up and diagnosis of bladder cancer is highly needed. Several markers have been studied with regard to sensitivity and specificity in detecting bladder cancer. Comparison of studies is complicated by limited data on tumor characteristics and treatment details. Many studies do not differentiate between primary and recurrent tumors, nor is the performance of the studied marker assessed separately in superficial and invasive or high- versus low-grade tumors.

AREAS COVERED IN THIS REVIEW

The field of bladder cancer biomarker research from the past 15 years. WHAT THE READER GAIN: A summary of the current field of bladder biomarker research with concluding remarks on some specific challenges in developing biomarkers for improved diagnosis and monitoring the disease.

TAKE HOME MESSAGE

In general, the best new markers give higher sensitivity than urinary cytology, but specificity is usually lower. By using new markers, the intervals between follow-up cystoscopies can be increased and the detection of relapse can be improved. But to date no non-invasive biomarker has proven to be sensitive and specific enough available to replace cystoscopy, neither in the diagnosis nor in the follow-up of bladder cancer. However, new marker combinations and algorithms for risk assessment hold promise for the future.

Biomarkers in oncology research and treatment: early detection research network: a collaborative approach

Several important criteria are essential for the development of biomarkers in clinical oncology. First, the biomarkers should be easily measured using standardized and cost-efficient methods. Second, biomarkers should be easily attainable from clinical materials such as body fluids and cells. Third, biomarkers should have clearly defined cutoff values with high sensitivity and specificity. Lastly, the predictive value of biomarkers should be possible in strata as large as possible. Single biomarkers may not be able to meet all of these criteria, which necessitates the development of biomarker panels. High-throughput technologies will be necessary for measuring these biomarker sets and translation of these methods into a clinical setting will be necessary in order to employ these biomarkers in a healthcare setting. One of the most important aspects of biomarker development will be standardization and statistical evaluation of biomarker studies. Guidelines for biomarker studies need to be developed that will enable standardization to take place. The Early Detection Research Network has been in the forefront of this objective. Early detection of cancer through appropriately validated biomarkers will provide for decreased morbidity and mortality and allow for the development of new therapeutic tools targeted specifically toward eradication of these early malignancies, hopefully increasing the survival rate of patients diagnosed with early-stage cancer.

Analysis of fluorescence in situ hybridization, mtDNA quantification, and mtDNA sequence for the detection of early bladder cancer

We designed this study to test the sensitivities of cytology, the nuclear matrix protein 22 (NMP22) assay, and fluorescence in situ hybridization (FISH) in the early detection of urothelial carcinoma, and to identify mtDNA alterations in urinary epithelial cells. We collected 41 urine samples and 26 corresponding peripheral blood samples from patients with clinically suspected urothelial carcinoma. The FISH and NMP22 assays detected 92.1% of the cancers, and cytology detected 60.5%. In the low-grade group, NMP22 and FISH analyses were more sensitive than cytology, but in the high-grade group, all three methods showed approximately 90% sensitivity. Overall, the FISH and NMP22, or FISH and cytology assays combined detected 97.4% of cancers, while cytology with NMP22 detected 92.1%. In the low-grade group, the sensitivity of the three methods combined was above 80%, but in high-grade group, the combined sensitivity was approximately 100%. In the mtDNA control region, we detected characteristic heteroplasmic mtDNA substitution mutations in 1 patient and a mtDNA length heteroplasmic mutation in 303 polyC or 16184 poly C in 20 patients. Overall, urothelial carcinoma-specific mtDNA mutations were observed in 20 of the 26 patients (76.9%). The average mtDNA copy numbers in urine samples and corresponding peripheral blood samples (83.45 +/- 60.36 and 39.0 +/- 24.38, respectively) (mean +/- standard deviation [SD]) differed significantly (P < 0.001). The mtDNA copy numbers in the urine samples from patients with high-grade and low-grade tumors (81.83 +/- 67.78 and 86.49 +/- 46.69, respectively) did not differ significantly (P = 0.589). In conclusion, the FISH assay showed the highest sensitivity for detecting low-grade urothelial carcinoma, and mtDNA copy numbers in urine samples were higher than those in the corresponding peripheral blood samples. The frequency of mtDNA mutations in the D-loop region in patients with cancer was approximately 80% in our study. This report further supports the significance of genetic alteration in urothelial carcinoma and the clinical utility of the FISH, mtDNA quantitation polymerase chain reaction, mtDNA sequencing, and capillary electrophoresis for this purpose.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for use of tumor markers in liver, bladder, cervical, and gastric cancers

BACKGROUND

Updated National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

METHODS

Published reports relevant to use of tumor markers for 4 cancer sites--liver, bladder, cervical, and gastric--were critically reviewed.

RESULTS

Alpha-fetoprotein (AFP) may be used in conjunction with abdominal ultrasound for early detection of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or cirrhosis associated with hepatitis B or C virus infection. AFP concentrations >200 microg/L in cirrhotic patients with typical hypervascular lesions >2 cm in size are consistent with HCC. After a diagnosis of HCC, posttreatment monitoring with AFP is recommended as an adjunct to imaging, especially in the absence of measurable disease. Although several urine markers have been proposed for bladder cancer, none at present can replace routine cystoscopy and cytology in the management of patients with this malignancy. Some may, however, be used as complementary adjuncts to direct more effective use of clinical procedures. Although carcinoembryonic antigen and CA 19-9 have been proposed for use gastric cancer and squamous cell carcinoma antigen for use in cervical cancer, none of these markers can currently be recommended for routine clinical use.

CONCLUSIONS

Implementation of these recommendations should encourage optimal use of tumor markers for patients with liver, bladder, cervical, or gastric cancers.

Fibroblast growth factor receptor 3 mutation in voided urine is a useful diagnostic marker and significant indicator of tumor recurrence in non-muscle invasive bladder cancer

The fibroblast growth factor receptor (FGFR)-3 gene encodes a receptor tyrosine kinase that is frequently mutated in non-muscle invasive bladder cancer (NMIBC). A sensitive and quantitative assay using peptide nucleic acid-mediated real-time PCR was developed for detecting FGFR3 mutations in the urine samples and evaluated as a molecular marker for detecting intravesical recurrence of NMIBC in patients undergoing transurethral resection of bladder tumor. FGFR3 mutation was examined in tumor tissues and serially taken pre- and postoperative urine sediments in 45 NMIBC patients with a median follow up of 32 months. FGFR3 mutations were detected in 53.3% (24/45) of primary tumor tissues, among which intravesical recurrence developed in 37.5% (9/24) of cases. FGFR3 mutation in the primary tumor was not a significant prognostic indicator for recurrence, while the proportion of FGFR3 mutation (i.e. tumor cellularity was >or=11%) in the preoperative urine sediments was a significant indicator for recurrence in patients with FGFR3 mutations in the primary tumors. FGFR3 mutations were detected in 78% (7/9) of postoperative urine samples from recurrent cases with FGFR3 mutations in the tumor, while no mutations were detected in the urine of 15 non-recurrent cases. Urine cytology was negative in all cases with FGFR3 mutations in the primary tumors, while the sensitivity of cytological examination was as high as 56% (5/9) in cases showing wild-type FGFR3 in the primary tumors. Urine FGFR3 mutation assay and cytological examination may be available in the future as complementary diagnostic modalities in postoperative management of NMIBC.

Clinical states model for biomarkers in bladder cancer

Bladder cancer is a significant healthcare problem in the USA, with a high recurrence rate, the need for expensive continuous surveillance and limited treatment options for patients with advanced disease. Research has contributed to an understanding of the molecular pathways involved in the development and progression of bladder cancer, and that understanding has led to the discovery of potentially diagnostic, predictive and prognostic biomarkers. In this review, a clinical states model of bladder cancer is introduced and integrated into a paradigm for biomarker development. Biomarkers are systematically incorporated with predefined end points to aid in clinical management.

The utility of fluorescence in situ hybridization for detection of bladder urothelial carcinoma in routine clinical practice

To evaluate the ability of fluorescence in situ hybridization (FISH) in detecting bladder urothelial carcinoma (BUC), FISH and cytology were compared for the evaluation of 308 consecutive urine samples from patients suspected of having BUC. All patients underwent cystoscopy for identification of bladder lesions. The FISH results were compared with the cytology assessment. In all, 122 patients had confirmed BUC. Among them, 68 (55.7%) were FISH-positive, while only 33 (27%) were positive on cytology. According to disease stage (superficial vs. invasive) and grade (low vs. high), the sensitivities of FISH were also significantly higher than those of cytology in all categories. Moreover, in 36 patients who had no visible tumor with flat, erythematous mucosa (suspicious lesion), FISH was more sensitive than cytology for the detection of BUC (83.3% vs. 33.3%, P=0.002). The FISH was negative in 168 (90.3%) of 186 patients with no histological evidence of BUC or negative cystoscopy findings. The sensitivity of FISH for detecting BUC was superior to that of cytology, regardless of tumor stage and grade. FISH is a significant additional and complementary method for detection of BUC in patients who have suspicious lesions on cystoscopy.

Molecular markers for detection, surveillance and prognostication of bladder cancer

Many markers for the detection of bladder cancers have been tested and almost all urinary markers reported are better than cytology with regard to sensitivity, but they score lower in specificity. Currently molecular and genetic changes play an important role in the discovery of new molecular markers for detection, prognostication and surveillance. The purpose of this review is to highlight the most important urinary molecular biomarker developments that have been studied and reported recently. In the current review we have summarized the most recent and relevant published reports on molecular urinary markers. The results of this review show that the first generation of urinary markers did not add much to urinary cytology. The current generation of markers is better, but additional clinical trials are needed. Our knowledge of molecular pathways in bladder cancer is growing and new methods of marker development emerge, but the perfect marker is still to be found. Currently, there are not clinically usable molecular markers that can guide us in diagnosis or surveillance, nor guide us in lowering the frequency of urethrocystoscopy in bladder cancer.

Increase sensitivity in detecting superficial, low grade bladder cancer by combination analysis of hypermethylation of E-cadherin, p16, p14, RASSF1A genes in urine

OBJECTIVES

To identify a better set of DNA methylation markers to detect superficial, low grade cancer cell in urine sediment for improving cancer treatment, morbidity, and mortality.

MATERIALS AND METHODS

Methylation-specific PCR (MSP) assay was used to detect promoter hypermethylation in 4 genes (E-cadherin, p16, p14, and RASSF1A) to identify reliable biomarkers for bladder cancer diagnosis in primary tumor DNA and urine sediment DNA from 57 bladder cancer patients. Urine DNA was compared with 20 healthy controls.

RESULTS

Fifty-one (90%) tumor DNA and 47 urine DNA (83%) samples from bladder cancer patients revealed hypermethylation in at least 1 of the 4 analyzed genes, whereas all urine samples from normal controls were negative. The sensitivity of MSP assay for detecting E-cadherin, p16, p14 and RASSF1A in tumor cells in voided urine was 35%, 35%, 33%, and 65%, respectively. Diagnostic sensitivity was 75% for combining RASSF1A and p14, and 83% for RASSF1A, p14 and E-cadherin. Urine cytology, however, detect only 13 (28%) cases of cancer or suspicious cancer. For detecting superficial and invasive bladder tumor, urine cytology revealed a sensitivity of 23% (6/26) and 35% (7/20), respectively. In contrast, MSP detected hypermethylation in the urine of 80% (37/46) bladder cancer patients. Moreover, hypermethylation analysis of E-cadherin, p14 or RASSF1A genes in urine sediment DNA detected in 85% (22/26) of superficial, 85% (11/13) of low grade, 75% (15/20) of invasive and 79% (26/33) of high grade bladder cancers. Importantly, hypermethylation was detected in the urine DNA of 90% (18/20) superficial tumors with negative or atypia cytology.

CONCLUSIONS

Hypermethylation of E-cadherin, p14 or RASSF1A in urine sediment DNA is a potential biomarker for detecting superficial, low grade cancer. Besides, hypermethylation of these 3 genes is a valuable adjunct diagnostic marker to urine cytology, which can enhance the diagnostic accuracy and follow-up treatment of bladder cancer patients.

Microsatellite analysis of voided-urine samples for surveillance of low-grade non-muscle-invasive urothelial carcinoma: feasibility and clinical utility in a prospective multicenter study (Cost-Effectiveness of Follow-Up of Urinary Bladder Cancer trial [CEFUB])

BACKGROUND

Microsatellite analysis (MA) of voided-urine samples has been promoted as an alternative for cystoscopy surveillance (UCS) of patients with low-grade non-muscle-invasive papillary urothelial carcinoma (UC).

OBJECTIVE

To assess the feasibility and clinical utility of MA on voided-urine samples in a routine setting to detect or predict bladder cancer recurrences.

DESIGN, SETTING, AND PARTICIPANTS

We evaluated 228 patients monitored by MA of voided-urine samples and synchronous UCS who participated in a longitudinal prospective study in 10 hospitals. Follow-up started after diagnosis of a primary or recurrent pTa, pT1, grade 1 or grade 2 papillary UC.

MEASUREMENTS

Clinico-pathological parameters and fibroblast growth factor receptor 3 (FGFR3) gene mutation status of the inclusion tumour were determined. MA outcome was analysed in 1012 urine samples during a mean follow-up of 41 mo. Poor DNA quality prevented MA in 19% (197/1012) of the samples, leaving 815 visits for a cross-sectional analysis of sensitivity and specificity. We determined the predictive value (PPV) in a longitudinal analysis for 458 series with persistent MA results. Factors influencing diagnostic quality of MA were investigated. Kaplan-Meier analysis was performed to relate MA results to recurrence.

RESULTS AND LIMITATIONS

Cross-sectional sensitivity and specificity of MA for detection of a recurrence were 58% (49/84) and 73% (531/731), respectively. One pT1 grade 3 UC was missed. In a longitudinal analysis, the 2-yr risk to develop a recurrence reached 83% if MA outcome was persistently positive and 22% when MA was persistently negative. PPV of MA was higher with wild-type FGFR3 gene status and smoking habits. All four upper urinary tract tumours detected were preceded by a positive MA test.

CONCLUSIONS

Consecutive positive MA results are a strong predictor for future recurrences, but sensitivity needs to be improved, for example, by patient selection and testing of additional genetic markers in urine samples.

The role of helminth infections in carcinogenesis

This review examines the significant literature on the role of helminth infections in carcinogenesis. Both parasitic infections and cancer have complex natural histories and long latent periods during which numerous exogenous and endogenous factors interact to obfuscate causality. Although only two helminths, Schistosoma haematobium and Opisthorchis viverrini, have been proven to be definitely carcinogenic to humans, others have been implicated in facilitating malignant transformation. The known mechanisms of helminth-induced cancer include chronic inflammation, modulation of the host immune system, inhibition of intracellular communication, disruption of proliferation-antiproliferation pathways, induction of genomic instability and stimulation of malignant stem cell progeny. Approximately 16% of all cancer cases worldwide are attributable to pathogenic agents, including schistosomes and liver flukes. This equates to 1,375,000 preventable cancer deaths per year. Means to reduce the incidence of helminth-associated malignancies are discussed.

Urinary markers in bladder cancer

OBJECTIVES

Many markers for the detection of bladder cancers have been tested. Almost all urinary markers reported are better than cytology with regard to sensitivity, but they score lower in specificity. The purpose of this review is to highlight the most important urinary biomarkers studied and reported recently.

METHODS

Literature on bladder cancer markers has been reviewed regularly in the last few years. In the current review we have tried to summarise the most recent literature of urinary markers.

RESULTS

The results of this review show that the first-generation urinary markers did not add much to urinary cytology. The current generation of markers is promising but larger clinical trails are needed. The future of marker development is bright with new techniques emerging, but the perfect marker is still to be found.

CONCLUSION

Currently, no single marker can yet guide us in surveillance and lower the frequency of urethrocystoscopy.

Detection of bladder cancer from the urine using fluorescence in situ hybridization technique

The authors report on their first experiences with the UroVysion fluorescence in situ hybridization (FISH) kit developed for the detection of bladder cancer. This new non-invasive diagnostic application of the FISH technique in the field of urology was elaborated to replace cystoscopy. The special urine examination method detects genetic alterations of the urothelial cells found in the urine, using fluorescent directlabeled DNA probes binding to the peri-centromeric regions of chromosomes 3, 7 and 17 as well as on the 9p21 locus. We aimed to evaluate the utility of UroVysion test in the light of the histological diagnosis. Urine samples from 43 bladder cancer patients and 12 patients with no or benign alterations were studied using a new application of FISH technique: the UroVysion reagent kit. The obtained FISH results were compared with the histological findings of the transurethral surgical resection specimens. The study rated the specificity and sensitivity of the technique 100% and 87%, respectively. Therefore, the technique could well fit into the diagnostic process of bladder carcinomas. Statistical analyses showed significant correlation between tumor progression and the severity of the genetic alterations detected by this FISH technique. Furthermore, positive correlation was found between tumor grade and the proportion of tumor cells showing genetic abnormality. The noninvasiveness, the robustness of evaluation and the high specificity/sensitivity are all in favor of this technique. The disadvantages are the higher costs of the technical background and the required future clinical studies to determine whether this technique can replace cystoscopy.

Detailed technical analysis of urine RNA-based tumor diagnostics reveals ETS2/urokinase plasminogen activator to be a novel marker for bladder cancer

BACKGROUND

The noninvasive detection of RNA tumor markers in body fluids represents an attractive diagnostic option, but diagnostic performance of tissue-derived markers is often poorer when measured in body fluids rather than in tumors. We aimed to develop a procedure for measurement of tumor RNA in urine that would minimize donor-dependent influences on the results.

METHODS

RNA isolated from urinary cell pellet, cell-depleted fraction, and whole urine was quantified by reverse transcription quantitative-PCR. The donor-dependent influence of urine background on individual steps of the standardized procedure was analyzed using an external RNA standard. Using a test set of samples from 61 patients with bladder cancer and 37 healthy donors, we compared 4 putative RNA tumor markers identified in whole urine with 5 established, tissue-derived RNA tumor markers for the detection of bladder cancer.

RESULTS

Of the markers analyzed by this system, the RNA ratio of v-ets erythroblastosis virus E26 oncogene homolog 2 (avian; ETS2) to urokinase plasminogen activator (uPA) enabled the most specific (100%) and sensitive (75.4%) detection of bladder cancer from whole urine, with an area under the curve of 0.929 (95% CI 0.882-0.976).

CONCLUSIONS

The described methodology for RNA marker detection in urine appears to be clinically applicable. The ratio of ETS2 mRNA to uPA mRNA in urine is a potential marker for bladder cancer.

Patients' perceived burden of cystoscopic and urinary surveillance of bladder cancer: a randomized comparison

OBJECTIVE

To compare, in patients with non-muscle-invasive low-grade (pTa/pT1, G1/G2) urothelial cell carcinoma of the urinary bladder, the perceived burden of flexible cystoscopy or surveillance by microsatellite analysis (MA) in voided urine, as such patients are normally recommended to adhere to regular cysto-urethroscopic surveillance (CUS).

PATIENTS AND METHODS

In all, 220 participants of a randomized trial comparing CUS and surveillance by MA were asked to complete questionnaires 1 week after cystoscopy or urine sample collection. We assessed the discomfort and pain reported during CUS, experiences with MA, and physical symptoms, medical consumption and general functioning in the week after CUS/urine sampling.

RESULTS

We analysed data from 732 questionnaires (197 patients) completed after CUS and 184 (67 patients) after collecting urine. The introduction of the cystoscope was reported to cause discomfort in 39% and pain in 35% of the responses to the questionnaires; the waiting time for the results of MA was reported as burdensome in 19%. Painful micturition was significantly more frequent in the week after CUS than after MA (30% and 12%, respectively). The frequency of fever (1% and 2%) and haematuria (7% and 6%) was similar in both groups. Older patients reported significantly less pain and discomfort from cystoscopy, and this was not related to having more previous cystoscopies.

CONCLUSION

CUS caused pain and discomfort in about a third of patients. The burden of MA appeared fully attributable to the waiting time for the test result. The present results are a further motivation in the search for less invasive surveillance tests.

Gene methylation and early detection of genitourinary cancer: the road ahead

DNA methylation is a common mechanism of inactivation of tumour-suppressor and other cancer genes in neoplastic cells. The advantages of gene methylation as a target for the detection and diagnosis of cancer in biopsy specimens and non-invasive body fluids such as urine or blood has led to many studies of application in genitourinary cancer. Here, we consider the background, promise and status, challenges and future directions of gene methylation and its clinical utility for the early detection of genitourinary cancer. The challenges of, and strategies for, advancing gene-methylation-based detection are relevant to all types of cancer.

Nucleic acid-based marker approaches to urologic cancers

There are numerous molecular modifications known to occur in cancer. New nucleic acid-based biomarkers provide a unique approach to patient management in urologic oncology. Malignant transformation of a normal cell requires a series of epigenetic and genetic changes or "hits." Epigenetics produced by deoxyribonucleic acid methylation, adding a methyl group to the fifth position of cytosine within CpG dinucleotides, are important players in deoxyribonucleic acid repair, genome instability, and regulation of chromatin structure. Genetic alterations in cancer can include mutations, chromosome deletions, insertions, amplifications, and translocations. In addition, the modifications of telomeres are critical to the maintenance of chromatin structure, transcription, and cell function in cancer. We review only nucleic acid-based molecular biomarkers in urologic oncology that can assist the clinician in establishing the diagnosis of disease, or that can predict the behavior of the disease or the patient's survival.

Intérêt des marqueurs urinaires dans le diagnostic et le suivi des tumeurs urothéliales de vessie

Urothelial bladder tumours require regular surveillance: cystoscopy associated with urine cytology are reference examinations. Several new markers currently under evaluation or already validated have recently been proposed to replace cytology and potentially reduce or even replace unnecessary cystoscopies. The biological fluid studied for all of these markers is the same as that of urine cytology, i.e. urine. The authors review the results of recent studies on these new urinary markers. The results of these markers demonstrate a better global sensitivity than urine cytology, but often a lower specificity. In the majority of cases, these tests are performed during patient follow-up (NMP22, BTA, CYFRA 21-l., etc.), but do not replace cystoscopy, due to a large number of false-positives. Other techniques, such as FISH, uCyt+ or microsatellites appear to be more promising, especially for the diagnosis of low-grade tumours. The best solution in practice may consist of a combination of several markers to further improve sensitivity and to decrease the false-positive rate responsible for unnecessary cystoscopies.

Improved detection of bladder carcinoma cells in voided urine by standardized microsatellite analysis

Successful treatment of bladder cancer depends largely on early diagnosis of primary and recurrent disease. Sensitive, specific and noninvasive procedures for detection are especially needed for grade 1 and 2 bladder tumors, because of the relatively low sensitivity of cytology. Here we introduce a novel strategy to improve the sensitivity and reliability of microsatellite analyses by employing marker-specific threshold values for loss-of-heterozygosity (LOH) at 10 loci. These individual cut-offs were experimentally determined with 35 normal control tissues and subsequently validated in a retrospective study with bladder cancer biopsies from 86 patients. In a prospective analysis of voided urines samples and matched blood probes from 91 patients, LOH-analysis, UroVysion FISH and conventional urine cytology were compared with histological findings of consecutive transurethral biopsies. Whereas all samples could be analyzed by our LOH assay, only 56 samples were suitable for all 3 analyses. The highest sensitivity was obtained with our LOH-assay/cytology approach (G1-2: 72%; G3: 96%) being only surpassed by a combination of all 3 techniques (G1-2: 83%; G3: 100%). Since over 93% of the patients with recurrent disease were identified by LOH/cytology-analyses of their voided urine samples, a monitoring scheme alternating cystoscopy with LOH/cytology-examination could now be envisioned to reduce invasive interventions and consequently improve follow-up compliance, especially in patients with low grade tumors.

Molecular Markers of Urothelial Cancer and Their Use in the Monitoring of Superficial Urothelial Cancer

Multiple molecular markers have been described for use in bladder cancer patients. Some of these have been studied more extensively than others, and it is difficult for the clinician to maintain a perspective over the myriad findings that have been made. We have reviewed a selection of markers used for surveillance with an emphasis on clinical utility. The best studied markers and those with the most promising preliminary results were selected. Only studies that included surveillance for recurrence in patients with a history of bladder cancer were considered. Each marker is briefly described and its performance in monitoring bladder cancer patients is summarized. Several promising markers are available, although only four have obtained US Food and Drug Administration approval. The clinical applications that have been studied include replacement or reduction in the number of cystoscopies performed in the surveillance of bladder cancer patients, substitution for or complementary use with urinary cytology in the same setting, predicting disease recurrence and progression, and predicting and monitoring treatment response. None of the markers have been proved sensitive and specific enough to replace cystoscopy. Others, such as nuclear matrix protein 22 (NMP22) and UroVysion, appear to have some utility when used to complement or replace cytology. The other applications have not been adequately studied for any given marker. While multiple molecular markers exist for bladder cancer, their full clinical utility will not be realized until more multicenter prospective trials are conducted to verify their efficacy and safety in the monitoring of patients with superficial bladder cancer.

Toward critical evaluation of the role(s) of molecular biomarkers in the management of bladder cancer

Among genitourinary malignancies, bladder cancer is a common, potentially dangerous and exceedingly costly disease entity. Predicated on substantial gains in our understanding of the natural history and molecular biology of bladder cancer, recent years have seen an explosion of new applied technologies to aid clinicians in the management of bladder cancer. Herein we present a systematic overview of general conceptual issues and specific strategies of potential relevance to the clinical evaluation of patients with bladder cancer. A number of basic epidemiological issues provide the relevant background within which we should consider candidate biomarkers. Within this framework, we highlight a number of important recent research findings representative of the large number of candidate bladder cancer biomarkers that have emerged. With several markers already having obtained regulatory approval for clinical use, this topic is of clear relevance not only to researchers but also to the practicing physician. Bladder cancer is a common, costly, and potentially dangerous disease with the opportunity for significant technological inroads in the area of applied biomarkers. An appreciation of basic epidemiological considerations informs our consideration of the state of the art and identifies specific strategies amenable to further innovation.

Quantitation of promoter methylation of multiple genes in urine DNA and bladder cancer detection

BACKGROUND

The noninvasive identification of bladder tumors may improve disease control and prevent disease progression. Aberrant promoter methylation (i.e., hypermethylation) is a major mechanism for silencing tumor suppressor genes and other cancer-associated genes in many human cancers, including bladder cancer.

METHODS

A quantitative fluorogenic real-time polymerase chain reaction (PCR) assay was used to examine primary tumor DNA and urine sediment DNA from 15 patients with bladder cancer and 25 control subjects for promoter hypermethylation of nine genes (APC, ARF, CDH1, GSTP1, MGMT, CDKN2A, RARbeta2, RASSF1A, and TIMP3) to identify potential biomarkers for bladder cancer. We then used these markers to examine urine sediment DNA samples from an additional 160 patients with bladder cancers of various stages and grades and from an additional 69 age-matched control subjects. Data were analyzed on the basis of a prediction model and were internally validated using a jacknife procedure. All statistical tests were two-sided.

RESULTS

For all 15 patients with paired DNA samples, the promoter methylation pattern in urine matched that in the primary tumors. Four genes displayed 100% specificity. Of the 175 bladder cancer patients, 121 (69%, 95% confidence interval [CI] = 62% to 76%) displayed promoter methylation in at least one of these genes (CDKN2A, ARF, MGMT, and GSTP1), whereas all control subjects were negative for such methylation (100% specificity, 95% CI = 96% to 100%). A logistic prediction model using the methylation levels of all remaining five genes was developed and internally validated for subjects who were negative on the four-gene panel. This combined, two-stage predictor produced an internally validated ROC curve with an overall sensitivity of 82% (95% CI = 75 % to 87%) and specificity of 96% (95% CI = 90% to 99%).

CONCLUSION

Testing a small panel of genes with the quantitative methylation-specific PCR assay in urine sediment DNA is a powerful noninvasive approach for the detection of bladder cancer. Larger independent confirmatory cohorts with longitudinal follow-up will be required in future studies to define the impact of this technology on early detection, prognosis, and disease monitoring before clinical application.