THE MOLECULAR DETECTION OF CIRCULATING TUMOR CELLS IN BLADDER CANCER USING TELOMERASE ACTIVITY

Liquid biopsies for detection, surveillance, and prognosis of urothelial cancer: a future standard?

INTRODUCTION

Liquid biopsies are used for the detection of tumor-specific elements in body fluid. Their application in prognosis and diagnosis of muscle/non-muscle invasive bladder cancer (MIBC/NMIBC) or upper tract urothelial cancer (UTUC) remains poorly known and rarely mentioned in clinical guidelines.

AREAS COVERED

Herein, we provide an overview of current data regarding the use of liquid biopsies in urothelial tumors.

EXPERT OPINION

Studies that were included analyzed liquid biopsies using the detection of circulating tumor cells (CTCs), deoxyribonucleic acid (DNA), ribonucleic acid (RNA), exosomes, or metabolomics. The sensitivity of blood CTC detection in patients with localized cancer was 35% and raised to 50% in patients with metastatic cancer. In NMIBC patients, blood CTC was associated with poor prognosis, whereas discrepancies were seen in MIBC patients. Circulating plasma DNA presented a superior sensitivity to urine and was a good indicator for diagnosis, follow-up, and oncological outcome. In urine, specific bladder cancer (BC) microRNA had an overall sensitivity of 85% and a specificity of 86% in the diagnosis of urothelial cancer. These results are in favor of the use of liquid biopsies as biomarkers for in urothelial cancer management.

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.

Do circulating tumor cells have a role in deciding on adjuvant chemotherapy after radical cystectomy?

Radical cystectomy (RC) with bilateral pelvic lymphadenectomy with or without perioperative chemotherapy is the golden standard treatment in muscle invasive and recurrent high-grade non-muscle invasive urothelial carcinoma of the bladder (UCB). Despite treatment with curative intent, up to 50% of patients develop metastasis and die from UCB due to micro-metastatic disease undetectable for current staging techniques prior to definitive therapy. Tumor cell dissemination is a crucial step in the natural history of the metastatic cascade. Circulating tumor cells (CTC) are malignant epithelial cells detectable in the peripheral blood of patients with various malignancies. In UCB, CTC are detectable in a significant number of patients prior to RC and associated with inferior outcomes. In this review, we summarize the current literature regarding CTC in UCB, discussing their potential on clinical decision-making regarding multimodal treatment and implications on the application of novel targeted therapies in the future. There is reliable evidence that presence of CTC in clinically non-metastatic UCB patients treated with RC are a powerful predictor for unfavorable outcomes and may be useful for adjuvant chemotherapy decision-making and monitoring. However, currently, the evidence is limited, and thus, integration of CTC in future UCB clinical trials is strongly recommended to shed more light on the potential of this promising biomarker.

Application of a telomerase-based circulating tumor cell (CTC) assay in bladder cancer patients receiving postoperative radiation therapy: a case study

BACKGROUND

Muscle invasive bladder carcinoma is an often lethal disease that requires aggressive treatment. Improved assays would contribute to better risk prediction and clinical management of this disease. A telomerase-based assay to detect circulating tumor cells (CTCs) may usefully fulfill this role.

METHODS

Two patients (C1 and C2) were enrolled onto an IRB-approved bladder biomarker study before initiating post-operative radiation therapy (RT) for muscle invasive bladder carcinoma. Blood samples were taken at predefined intervals: before, during, and after RT and then retrospectively correlated with imaging studies and disease course.

RESULTS

C1 began RT for positive resection margins on surgical pathology, at which time CTCs were undetectable and pelvic imaging demonstrated no evidence of disease. However, following the completion of treatment, the patient's CTC count was found to have increased to 202 CTCs/mL, and MRI demonstrated new abdominal and pelvic masses consistent with progressive disease. C1 ultimately died of disease with distant and local failure. Conversely, C2 was found to have 632 CTCs/mL before the initiation of RT for positive surgical margins, although imaging demonstrated no visible masses. At the conclusion of RT, repeat imaging showed changes that were indeterminate for either tumor recurrence or post-radiation effects. However, the patient's CTC count had dropped to 184 CTCs/mL. Furthermore, a second follow-up assay performed 6 months later revealed no detectable CTCs and repeat imaging showed complete resolution of worrisome imaging changes, thus excluding tumor progression.

CONCLUSIONS

To our knowledge this is the first report of a telomerase-based assay to identify CTCs in bladder cancer patients. Further studies are required to fully determine the ultimate clinical utility of this assay. However, the two patient vignettes described here illustrate how serial CTC assays may track the disease course and inform the management of bladder cancer patients undergoing adjuvant RT and potentially chemotherapy.

Neoadjuvant chemotherapy improves survival rate in advanced urothelial carcinoma

Radical surgery (RS) with adjuvant chemotherapy (AC) or radiotherapy has been conventionally used for patients with advanced urothelial carcinoma (AUC). Recent research has indicated that systemic neoadjuvant chemotherapy (NC) with RS yields better outcomes than RS alone for patients with locally advanced bladder cancer. However, there are no reports indicating whether NC or AC would be beneficial for patients with AUC. The present study compared the survival rate for AUC patients receiving NC or AC. A retrospective analysis was conducted using data for 64 patients with AUC who underwent RS and systemic chemotherapy at our institution between March 2002 and March 2011. Of the 64 patients, 30 received NC before RS and 34 received RS followed by systemic AC. Pathologic stages (p=0.002), grades (p=0.018) and lymphovascular invasion (p=0.047) were significantly lower in the patients who received NC first than in those who received RC first. Furthermore, analysis of the surgical specimens revealed that 26.7% of patients who received NC before RS had complete remission. There were no significant differences in demographic data, surgical complications, and chemotoxicity between the two patient groups. The progression-free survival (PFS) and overall survival (OS) of patients who received initial NC were significantly better than those of patients who received initial RC (p=0.002 and 0.018, respectively). Our results indicate that NC administration before RS significantly improved the PFS and OS of AUC patients, without increasing surgical complications and chemotoxicity. Further prospectively controlled trials need to be conducted to confirm the effectiveness of NC for AUC patients.

Electrical fingerprinting, 3D profiling and detection of tumor cells with solid-state micropores

Solid-state micropores can provide direct information of ex vivo or in vitro cell populations. Micropores are used to detect and discriminate cancer cells based on the translocation behavior through micropores. The approach provides rapid detection of cell types based on their size and mechano-physical properties like elasticity, viscosity and stiffness. Use of a single micropore device enables detection of tumor cells from whole blood efficiently, at 70% CTC detection efficiency. The CTCs show characteristic electrical signals which easily distinguish these from other cell types. The approach provides a gentle and inexpensive instrument that can be used for specific blood analysis in a lab-on-a-chip setting. The device does not require any preprocessing of the blood sample, particles/beads attachment, surface functionalization or fluorescent tags and provides quantitative and objective detection of cancer cells.

Change of telomerase activity in peripheral whole blood of head and neck squamous cell carcinoma patients before and after surgery: a pilot study

BACKGROUND The purpose of this study was to evaluate telomerase activity in peripheral whole blood from head and neck squamous cell carcinoma (HNSCC) patients as a biomarker for diagnosis of HNSCC or detection of recurrence during follow-up. MATERIALS AND METHODS Telomerase activity was measured from peripheral whole blood extracts by telomerase repeat amplification protocol (TRAP) in HNSCC patients before and after surgery and in a control group. Sixty-two HNSCC patients and 42 control subjects were included. RESULTS Telomerase activity was found in 41 out of 62 (66.1%) HNSCC patients before surgery and in 8 out of 42 (19.0%) controls (p<0.001). Among 41 HNSCC patients who showed positive telomerase activity before surgery, 32 (78.1%) showed a conversion of telomerase activity to negative after surgery. In follow-up, 6 out of 8 (75%) showed conversion of telomerase activity from negative to positive after recurrence. Telomerase activity was changed to negative in 4 out of 6 (66%) recurred patients with positive telomerase activity after second surgery. CONCLUSION The telomerase activity in peripheral whole blood extracts of HNSCC patients might be a useful biomarker for detecting recurrence after treatment. Further study with larger sample size using a more sensitive detection method of telomerase activity is necessary to verify these results.

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.

Highly efficient circulating tumor cell isolation from whole blood and label-free enumeration using polymer-based microfluidics with an integrated conductivity sensor

A novel microfluidic device that can selectively and specifically isolate exceedingly small numbers of circulating tumor cells (CTCs) through a monoclonal antibody (mAB) mediated process by sampling large input volumes (>/=1 mL) of whole blood directly in short time periods (<37 min) was demonstrated. The CTCs were concentrated into small volumes (190 nL), and the number of cells captured was read without labeling using an integrated conductivity sensor following release from the capture surface. The microfluidic device contained a series (51) of high-aspect ratio microchannels (35 mum width x 150 mum depth) that were replicated in poly(methyl methacrylate), PMMA, from a metal mold master. The microchannel walls were covalently decorated with mABs directed against breast cancer cells overexpressing the epithelial cell adhesion molecule (EpCAM). This microfluidic device could accept inputs of whole blood, and its CTC capture efficiency was made highly quantitative (>97%) by designing capture channels with the appropriate widths and heights. The isolated CTCs were readily released from the mAB capturing surface using trypsin. The released CTCs were then enumerated on-device using a novel, label-free solution conductivity route capable of detecting single tumor cells traveling through the detection electrodes. The conductivity readout provided near 100% detection efficiency and exquisite specificity for CTCs due to scaling factors and the nonoptimal electrical properties of potential interferences (erythrocytes or leukocytes). The simplicity in manufacturing the device and its ease of operation make it attractive for clinical applications requiring one-time use operation.

High detection rate of circulating tumor cells in blood of patients with prostate cancer using telomerase activity

BACKGROUND

Circulating tumor cells (CTCs) cannot be readily detected with currently available methods in the majority of patients with prostate cancer. Telomerase activation, one of the major immortalization events, is found in most cases of prostate cancer. We attempted to develop a method using telomerase activity to isolate CTCs in patients with prostate cancer.

PATIENTS AND METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from whole blood using Ficoll-Hypaque. Immunomagnetic beads coated with an epithelial cell-specific antigen antibody (BerEP4) were used to harvest epithelial cells from PBMCs. Telomerase activity was detected in harvested epithelial cells using the telomerase-PCR-enzyme-linked immunosorbent assay method.

RESULTS

Blood samples from 107 patients with prostate cancer were studied. CTCs were detected in 19 of 24 (79%) patients with advanced prostate cancer. In contrast, CTCs were not detected in blood samples from 22 healthy male volunteers. CTCs were even identified in patients with an undetectable (<0.1 ng/ml) serum prostate-specific antigen (PSA). CTCs were detected in 55 of 70 (79%) patients with localized prostate cancer before radical prostatectomy (n = 30) or brachytherapy (n = 40). CTCs were also detected in 3 of 13 patients (23%) with an undetectable serum PSA measured at least 1 year after radical prostatectomy, which is consistent with the expected relapse rate in this setting.

CONCLUSION

CTCs can be detected using telomerase activity in a large majority and a wide variety of patients with prostate cancer, including those with localized disease.

The prognostic value of telomerase expression in peripheral blood mononuclear cells of head and neck cancer patients

OBJECTIVE

This study investigates the expression of telomerase in the peripheral blood mononuclear cells (PBMCs) of head and neck cancer patients and the relationship between the telomerase expression in PBMCs and clinicopathological features with prognosis.

METHODS

Peripheral blood samples were collected from 100 head and neck squamous cell cancer patients and 20 normal control group. The telomerase activity in peripheral blood mononuclear cells was measured by telomerase rapid amplification protocol (TRAP) assay using TRAPeze telomerase detection kit. Pearson chi test was used to analyze the correlation of telomerase expression with clinicopathologic parameters. Kaplan-Meier method and Cox proportional hazards model were used for prognostic analysis.

RESULTS

Regarding the expression of telomerase in PBMCs of patients, 73 out of 100 (73.0%) were found to be positive, and the remaining 27 cases (27.0%) were negative. The difference to the telomerase expression of PBMCs in the normal and cancer patients was significant (P < 0.001). The expression of telomerase in PBMCs of patients was significant correlated with T classification (P = 0.005), N classification (P = 0.002), and AJCC stages (P < 0.001). On multivariate analysis, N classification (P = 0.007), AJCC stages (P = 0.02), and telomerase expression (P = 0.017) showed independent factors associated with poor survival.

CONCLUSION

The detection of telomerase expression in PBMCs of head and neck cancer patients is a simple and very useful molecular marker for the progression and prognosis of head and neck cancer.

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.

Colon cancer: prevalence, screening, gene expression and mutation, and risk factors and assessment

Colon cancer detection at an early stage and identifying susceptible individuals can result in reduced mortality from this prevalent cancer. Genetic events leading to the development of this cancer involve a multistage progression of adenoma polyps to invasive metastatic carcinomas. Currently, there is no satisfactory screening method that is highly specific, sensitive, or reliable. Dietary patterns associated with the greatest increase in colon cancer risk are the ones that typify a diet rich in fat and calories, and low in vegetable, fruits, and fibers. Genetic susceptibility to environmental carcinogenesis must be factored into the risk assessment for this cancer. Many genes have been shown to be associated with increased expression and mutations in colorectal cancer patients. These genes have been reviewed; it is hoped that by carefully selecting a number of them, a molecular approach that is suitable for arriving at a tumorigenic expression index is developed, which will reliably detect this cancer at an early stage (i.e., before it metastasizes), especially in exfoliated samples (e.g., stool and blood), so that appropriate intervention strategies can be implemented. Illustrated herein is the utility of employing real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantitatively measure gene expression, and develop an index that is specific for this cancer, which if perfected may result in a reliable and sensitive screening technique for colorectal cancer detection.