A comparison between microsatellite analysis and cytology of urine for the detection of 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.

Antibody-modified hydroxyapatite surfaces for the efficient capture of bladder cancer cells in a patient's urine without recourse to any sample pre-treatment

In this study, we describe a sensitive protocol for the detection of bladder cancer cells in a patient's urine without pre-treatment of the urine sample using antibody-modified hydroxyapatite (HAp) micro/nanostructured surfaces converted from natural seashells under mild biomineralization conditions.

Use of polymerase chain reaction analysis of urinary DNA to detect bladder carcinoma

A cohort of 113 patients underwent prospective evaluation with a panel of seven microsatellites, on chromosomes 9, 13 and 17. Thirty-seven patients had histologically confirmed bladder tumors, 53 patients had a history of previous transitional cell carcinoma of the bladder (TCC) but normal cystoscopies (control Group 1), and 23 patients had no previous history of TCC and normal cystoscopies (control Group 2). Urinary DNA was considered to show a deletion if an allele was reduced by more than 50%, and this was considered diagnostic of bladder carcinoma. The sensitivity of the method was 50%, positive predictive value was 80%, and specificity was 93%. Reducing the threshold for defining allelic loss increases sensitivity, but reduces specificity. The concentration of urinary DNA in the sample did not influence detection rate. The grade and stage of the bladder tumor did not influence the likelihood of detection. This method detects bladder carcinoma with high specificity, and increasing the number of microsatellites used should increase sensitivity.

Microsatellite analysis of urine sediment versus urine cytology for diagnosing transitional cell tumors of the urinary bladder

The aim was to evaluate microsatellite analysis of urine sediment (MAUS) as an alternative method to urine cytology for routine diagnosis of patients with transitional cell tumors (TCT) of the urinary bladder. Urine cytology has the advantage of being non-invasive, fast and cheap, but is of limited value because of its low sensitivity. MAUS has previously been found to be a successful alternative method. However, the experimental set-up of such investigations implied exclusion of samples with unfavorable characteristics and use of a large number of markers. In the present study, MAUS was tested on all samples routinely available and a small panel of markers was selected. The urine sediments of 66 TCT patients and 24 controls were analyzed by MAUS with 16 fluorescent markers and by urine cytology. All samples were analyzed, including the ones of later micturition, with gross hematuria, leukocyturia or absence of visible sediment. In patients with tumors of low grade (grades I-II), MAUS was significantly more sensitive than urine cytology. The two methods were of equivalent diagnostic power in high-grade (grades III-IV), high-stage (pT1-pT4) tumors. A panel of the six most informative markers for MAUS was selected. Although MAUS has an advantage over routine cytology in low-grade, low-stage tumors, an overall sensitivity of 45% is not sufficient for routine clinical use.

Tumor markers in the diagnosis of primary bladder cancer. A systematic review

PURPOSE

We systematically reviewed the available evidence, and obtained and compared summary estimates of the sensitivity and specificity of cytology and the urine based markers bladder tumor antigen, BTA stat (Polymedco, Redmond, Washington), BTA TRAK (Polymedco), NMP22 (Matritech, Cambridge, Massachusetts), telomerase and fibrin degradation product in detecting primary bladder cancer.

MATERIALS AND METHODS

Studies on the diagnosis of primary bladder cancer published from 1990 through November 2001 in English and German were retrieved from MEDLINE and EMBASE data bases. In our research we included studies that evaluated 1 or more of the markers, used cystoscopy as the reference standard and allowed the construction of a 2 x 2 contingency table for a per patient analysis. The data plus items on study and clinical characteristics were extracted by 2 observers. Sensitivity and specificity for each marker were estimated using a bivariate random effect meta-analysis. A multivariable analysis was performed to explain study variation.

RESULTS

A total of 42 studies were included in our review. Only 2 studies were available on fibrin degradation product, hence a meta-analysis was not possible. Cytology had the best specificity at 94% (95% CI: 90% to 96%). This figure was significantly better than that of the other markers except for telomerase (specificity 86% [71% to 94%]). Telomerase had the best sensitivity (75% [71% to 79%]) but it was not significantly better than that of BTA stat (70% [66% to 74%]). Case control designs yielded lower values for sensitivity for the tumor markers cytology, bladder tumor antigen and BTA stat.

CONCLUSIONS

Cytology has the best specificity and telomerase the best sensitivity. However, none of the markers studied here is sensitive enough to be recommended for daily routine.