Application of multiplex FISH, CGH and MSSCP techniques for cytogenetic and molecular analysis of transitional cell carcinoma (TCC) cells in voided urine specimens

Urinary markers in the everyday diagnosis of bladder cancer

Bladder cancer (BC) represents the fourth most common neoplasia in men and the ninth most common cancer in women, with a significant morbidity and mortality. Cystoscopy and voided urine cytology (involving the examination of cells in voided urine to detect the presence of cancerous cells) are currently the routine initial investigations in patients with hematuria or other symptoms suggestive of BC. Around 75-85% of the patients are diagnosed as having non-muscle-invasive bladder cancer (NMIBC). Despite the treatment, these patients have a probability of recurrence at 5 years ranging from 50 to 70% and of progression to muscle invasive disease of 10-15%. Patients with NMIBC must undergo life-long surveillance, consisting of serial cystoscopies, possibly urine cytology and ultrasonography. Cystoscopy is unsuitable for screening because of its invasiveness and costs; serial cystoscopies may cause discomfort and distress to patients. Furthermore, cystoscopy may be inconclusive, falsely positive or negative. Although urine cytology has a reasonable sensitivity for the detection of high-grade BC, it lacks sensitivity to detect low-grade tumors (sensitivity ranging from 4 to 31%). The overall sensitivity and specificity of urine cytology range from 7 to 100 and from 30 to 70%, respectively. There is a need for new urine biomarkers that may help in BC diagnosis and surveillance. A lot of urinary biomarkers with high sensitivity and/or specificity have been investigated. Although none of these markers have proven to be powerful enough to replace standard cystoscopy, some of them may represent accurate predictors of BC. A review of recent studies is presented.

Identification of prefoldin amplification (1q23.3-q24.1) in bladder cancer using comparative genomic hybridization (CGH) arrays of urinary DNA

BACKGROUND

Array-CGH represents a comprehensive tool to discover genomic disease alterations that could potentially be applied to body fluids. In this report, we aimed at applying array-CGH to urinary samples to characterize bladder cancer.

METHODS

Urinary DNA from bladder cancer patients and controls were hybridized on 44K oligonucleotide arrays. Validation analyses of identified regions and candidates included fluorescent in situ hybridization (FISH) and immunohistochemistry in an independent set of bladder tumors spotted on custom-made tissue arrays (n = 181).

RESULTS

Quality control of array-CGH provided high reproducibility in dilution experiments and when comparing reference pools. The most frequent genomic alterations (minimal recurrent regions) among bladder cancer urinary specimens included gains at 1q and 5p, and losses at 10p and 11p. Supervised hierarchical clustering identified the gain at 1q23.3-q24.1 significantly correlated to stage (p = 0.011), and grade (p = 0.002). The amplification and overexpression of Prefoldin (PFND2), a selected candidate mapping to 1q23.3-q24.1, correlated to increasing stage and tumor grade by means of custom-designed and optimized FISH (p = 0.013 and p = 0.023, respectively), and immunohistochemistry (p ≤0.0005 and p = 0.011, respectively), in an independent set of bladder tumors included in tissue arrays. Moreover, PFND2 overexpression was significantly associated with poor disease-specific survival (p ≤0.0005). PFND2 was amplified and overexpressed in bladder tumors belonging to patients providing urinary specimens where 1q23.3q24.1 amplification was detected by array-CGH.

CONCLUSIONS

Genomic profiles of urinary DNA mirrowed bladder tumors. Molecular profiling of urinary DNA using array-CGH contributed to further characterize genomic alterations involved in bladder cancer progression. PFND2 was identified as a tumor stratification and clinical outcome prognostic biomarker for bladder cancer patients.

Biomarkers for detection and surveillance of bladder cancer

INTRODUCTION

Bladder cancer is the fourth most common cancer in men and the ninth most common cancer in women in Canada. Early detection of tumours is essential for improved prognosis and long-term survival. The standard method for detection and surveillance is cystoscopy together with urine cytology. Cystoscopy is relatively sensitive but is expensive and invasive. Urinary cytology is a noninvasive method that has poor sensitivity but high specificity; it is relied on for the detection of carcinoma in situ. Currently, several urinary-based bladder tumour biomarkers with USFDA/Health Canada approval are available commercially, but none have been widely adopted by urologists despite their offering high sensitivity and/or specificity. We present here a review of recent studies evaluating 7 commercial biomarker assays for the detection and/or surveillance of bladder cancer.

RESULTS

SENSITIVITY AND SPECIFICITY RANGES, RESPECTIVELY, FOR EACH MARKER WERE REPORTED AS FOLLOWS: BTA Stat (Polymedco), 52.5%-78.0% and 69.0%-87.1%; BTA Trak (Polymedco), 51%-100% and 73%-92.5%; cytology, 12.1%-84.6% and 78.0%-100%; hematuria dipstick, 47.0%-92.6% and 51.0%-84.0%; NMP22 Bladder Cancer Test (Matritech), 34.6%-100% and 60.0%-95.0%; NMP22 BladderChek (Matritech), 49.5%-65.0% and 40.0%-89.8%; ImmunoCyt/uCyt+ (DiagnoCure), 63.3%-84.9% and 62.0%-78.1%; ImmunoCyt/uCyt+ and cytology, 81.0%-89.3% and 61.0%-77.7%; and UroVysion (Abbott Molecular)/florescence in situ hybridization, 68.6%-100% and 65.0%-96.0%.

CONCLUSION

We find that no currently available bladder cancer urinary marker is sensitive enough to eliminate the need for cystoscopy. In addition, cytology remains integral to the detection of occult cancer. However, owing to their relatively high sensitivities, these markers may be used to extend the period between cystoscopies in the surveillance of patients with transitional cell carcinoma. Further study is required to determine which markers, alone or in panel, would best accomplish this.

Fluorescence in situ hybridization for detecting urothelial carcinoma: a clinicopathologic study

BACKGROUND

Because urothelial carcinoma (UC) is associated with a significantly high risk of disease recurrence and progression, patients with UC require long-term surveillance. Fluorescence in situ hybridization (FISH) has been shown to be more sensitive than cytology in the detection of UC. The current study evaluated the use of FISH for detecting UC.

METHODS

A pathology database was used to identify patients who had urine cytology and FISH performed at the study institution between 2004 and 2006. Urinary specimens were analyzed using UroVysion FISH probes for abnormalities in centromeric chromosomes 3, 7, and 17 and locus-specific 9p21. FISH results were correlated with cytologic findings and a minimal clinical follow-up of 24 months.

RESULTS

A total of 1006 consecutive urinary specimens from 600 patients (448 men and 152 women) who were monitored for recurrent UC (915 specimens) or evaluated for urinary symptoms (91 specimens) were identified. On FISH analysis, 669 specimens were found to be negative for UC and 272 specimens were positive for UC. Sixty-five (6%) specimens were insufficient for FISH analysis. The sensitivity and specificity of FISH for UC were 58% and 66%, respectively, and 59% and 63%, respectively, when FISH and cytology results were combined. Factors contributing to decreased FISH sensitivity included the paucity or absence of tumor cells, low-grade tumors, degenerated cells, method of specimen collection, type of specimen, and obscuring inflammatory cells or lubricant.

CONCLUSIONS

UroVysion FISH appeared to have good sensitivity and specificity for detecting UC in urinary specimens. It is important to correlate the FISH results with the cytologic findings.

UroVysion FISH test for detecting urothelial cancers: meta-analysis of diagnostic accuracy and comparison with urinary cytology testing

OBJECTIVES

Since the introduction of the UroVysion test for detecting urothelial cancers in urine, its reported performance has varied. This article systematically analyzed reported results.

METHODS

Articles in English conforming to the Oxford EBM criteria were included, with the evaluation focused on cancers that were histologically confirmed at the time of testing rather than on any cancers that might develop later. Where applicable, samples with no cells were reclassified as negative so as to further improve the actual estimation of test performance. Where available, cytology data were also analyzed. Meta-DiSc software was used for the statistical analyses.

RESULTS

We identified 14 studies involving 2477 FISH tests. The overall prevalence of urothelial cancers was 35%. The pooled sensitivity and specificity of all studies were 72% (69%-75%) and 83% (82%-85%), respectively. Cytology data were available from 12 studies, with the overall sensitivity and specificity being 42% (38%-45%) and 96% (95%-97%). Excluding Ta tumors, the sensitivity was 86% (82%-89%) for UroVysion and 61% (56%-66%) for cytology. The overall performance was higher for UroVysion than for cytology: diagnostic odds ratio, 16.8 and 14.1; AUC, 0.867 (SE 0.021) and 0.626 (SE 0.091). These differences in overall test performance measures almost disappeared when superficial cancer cases were excluded from the analysis.

CONCLUSIONS

The published trials suggest that for a general mix of cases, cytology results are highly specific. However, a negative cytology result does not meaningfully change the post-test probability of the presence of urothelial cancer. UroVysion FISH test results should not be considered to provide conclusive evidence for the presence or absence of urothelial cancer, but both positive and negative results do moderately influence the post-test probability of disease.

Diagnostic significance of allelic imbalance in cancer

Allelic imbalance (AI), a deviation from the normal 1:1 ratio of maternal and paternal alleles, occurs in virtually all solid and blood-borne malignancies. The frequency and spectrum of AI in a tumor cell reflects the karyotypic complexity of the cancer genome. Hence, many investigations have assessed the extent of AI to analyze differences between normal and tumor tissues in a variety of different organs. In this review, the authors describe established and emerging technologies used to assess the extent of AI in human tissues, and their application in the diagnosis of cancer. The four major methods to be reviewed represent powerful and widely used tools for the identification of allelic imbalances accompanying cancer initiation and progression. These are fluorescent in situ hybridization, comparative genomic hybridization, single nucleotide polymorphism arrays and the use of microsatellite markers. For each method, the authors provide a brief description of the approach and elaborate on specific studies that highlight its utility in the diagnosis of human cancers.