Detection of Circulating Tumour Cells in Urothelial Cancers and Clinical Correlations: Comparison of Two Methods

Cytomorphologic visualization of circulating tumor cells in urinary bladder cancer patients using ScreenCell™ technology: Potential as a simple cytology test

Circulating tumor cells (CTC) are a recent technique which is a potentially important prognostic factor in many solid tumors. There are many techniques of detecting CTCs, but they usually implement costly techniques like EpCAM targeted detection, fluorescence-based diagnosis, or magnetic bead based positive or negative selection. The diagnostic utility of simple cytomorphological diagnosis after routine staining of CTCs have been rarely studied. We aimed to detect CTCs in 24 patients clinically suspected to have Urinary Bladder Cancer using a simple but efficient patented filtration technology (ScreenCell™), followed by optical microscopic visualization after routine May-Grunwald-Giemsa (MGG) staining. The detected CTCs were then tested for association with the histologic type, lamina propria invasion, deep muscle invasion and the T-stage. Out of the 24 patients tested, one was found to have papilloma, nine had low grade urothelial carcinoma, 13 had high grade urothelial carcinoma and one had poorly differentiated adenocarcinoma. Of these, two LGUC, eight HGUC and one adenocarcinoma had detectable CTC. Presence of CTCs had a statistically significant association with Lamina propria invasion (P = .006) and T-stage (P = .02), and a trend toward significance for differentiating LGUC from HGUC (P = .10). These results suggest that cytomorphological detection of CTC is likely to be clinically useful in diagnosis and prognostication of urinary blader cancers. These findings need to be confirmed on studies with larger sample sizes.

Circulating Tumor Cell Clusters Are Frequently Detected in Women with Early-Stage Breast Cancer

Simple Summary

Metastases cause the majority of breast cancer-related deaths. Circulating tumor cells (CTCs), and in particular CTC-clusters, are considered the seeds of metastasis, but their analysis in the early-stages of the disease has so far been limited by the fact that, by using conventional and epithelial-based technologies (as the FDA-approved CellSearch platform), they are more often detected in the metastatic setting. It is known, however, that cancer cells are heterogeneous and can downregulate the expression of epithelial markers, thus limiting the detection capability of epithelial-based technologies. Here, we show that it is possible to increase CTC-cluster detection by using an epithope-independent technology based on blood filtration, and in particular that this strategy allows to detect a high number of CTC-clusters in stage II-III breast cancer patients, before and during neoadjuvant treatment. Our results therefore offer a new opportunity to deepen our understanding of the cancer dissemination process in its early steps.

Abstract

The clinical relevance of circulating tumor cell clusters (CTC-clusters) in breast cancer (BC) has been mostly studied using the CellSearch^®, a marker-dependent method detecting only epithelial-enriched clusters. However, due to epithelial-to-mesenchymal transition, resorting to marker-independent approaches can improve CTC-cluster detection. Blood samples collected from healthy donors and spiked-in with tumor mammospheres, or from BC patients, were processed for CTC-cluster detection with 3 technologies: CellSearch^®, CellSieve™ filters, and ScreenCell^® filters. In spiked-in samples, the 3 technologies showed similar recovery capability, whereas, in 19 clinical samples processed in parallel with CellSearch^® and CellSieve™ filters, filtration allowed us to detect more CTC-clusters than CellSearch^® (median number = 7 versus 1, p = 0.0038). Next, samples from 37 early BC (EBC) and 23 metastatic BC (MBC) patients were processed using ScreenCell^® filters for attaining both unbiased enrichment and marker-independent identification (based on cytomorphological criteria). At baseline, CTC-clusters were detected in 70% of EBC cases and in 20% of MBC patients (median number = 2, range 0–20, versus 0, range 0–15, p = 0.0015). Marker-independent approaches for CTC-cluster assessment improve detection and show that CTC-clusters are more frequent in EBC than in MBC patients, a novel finding suggesting that dissemination of CTC-clusters is an early event in BC natural history.

Detection of Genomically Aberrant Cells within Circulating Tumor Microemboli (CTMs) Isolated from Early-Stage Breast Cancer Patients

Simple Summary

Distant metastases derive from the shedding and dissemination of single cancer cells (CTCs) or circulating tumor emboli (CTMs) into circulation. Previous studies on CTMs were mainly run in patients with metastatic disease; however, we observed that CTMs are more frequently detected in patients with early-stage breast cancer. Here, we collected single CTMs and their relative primary tumor tissue samples in early-stage patients. By studying genomic aberrations, present in tumors cells and absent in normal cells, we predicted the tumor fraction thanks to a statistical model developed from a calibration curve with breast cancer cell lines. The tumor fraction ranged from 8% to 48% and CTMs contained specific and shared alterations with respect to tissue. Thus, CTMs may derive from different regions of the primary tumor or from occult micrometastases. Moreover, CTM-private mutations may inform us about specific metastasis-associated functions of involved genes that should be further explored in follow-up and mechanistic studies.

Abstract

Circulating tumor microemboli (CTMs) are clusters of cancer cells detached from solid tumors, whose study can reveal mechanisms underlying metastatization. As they frequently comprise unknown fractions of leukocytes, the analysis of copy number alterations (CNAs) is challenging. To address this, we titrated known numbers of leukocytes into cancer cells (MDA-MB-453 and MDA-MB-36, displaying high and low DNA content, respectively) generating tumor fractions from 0–100%. After low-pass sequencing, ichorCNA was identified as the best algorithm to build a linear mixed regression model for tumor fraction (TF) prediction. We then isolated 53 CTMs from blood samples of six early-stage breast cancer patients and predicted the TF of all clusters. We found that all clusters harbor cancer cells between 8 and 48%. Furthermore, by comparing the identified CNAs of CTMs with their matched primary tumors, we noted that only 31–71% of aberrations were shared. Surprisingly, CTM-private alterations were abundant (30–63%), whereas primary tumor-private alterations were rare (4–12%). This either indicates that CTMs are disseminated from further progressed regions of the primary tumor or stem from cancer cells already colonizing distant sites. In both cases, CTM-private mutations may inform us about specific metastasis-associated functions of involved genes that should be explored in follow-up and mechanistic studies.

Detection of circulating tumor cells in patients with laryngeal cancer using ScreenCell: Comparative pre- and post-operative analysis and association with prognosis

The presence of circulating tumor cells (CTCs) in the blood of patients with metastatic breast, colorectal and prostate cancer have been widely investigated; however, few studies have examined CTCs in patients with laryngeal cancer. The present pilot study aimed to detect pre- and postoperative CTCs in the blood of patients with laryngeal cancer and evaluate the association with prognosis. Eight patients with laryngeal squamous cell carcinoma (LSCC) at stage III were included in the present study and underwent total or subtotal laryngectomy and radical bilateral neck lymph node dissection. Blood samples were collected from all patients before and after surgery at different time-points. The following processing steps were followed; preoperative blood sampling, surgery, postoperative blood sampling at 3, 6 and 12 month follow-ups, and prognostic association analysis. CTCs were retained on ScreenCell filters for cytological characterization. The presence of CTCs was associated with a less favorable prognosis, whereas a decrease of CTCs in the postoperative sampling was observed in patients who exhibited an improved therapeutic response. The results of the present pilot study revealed a possible association between the presence of CTCs and a less favorable prognosis in patients with LSCC; therefore, these preliminary findings may encourage further research into the incorporation of a liquid biopsy in the management of LSCC, as this may help identify patients with occult metastatic disease earlier and in a non-invasive manner. In addition, this approach may represent novel independent prognostic factor for use in the clinical evaluation of patients with LSCC.

Analysis of Single Circulating Tumor Cells in Renal Cell Carcinoma Reveals Phenotypic Heterogeneity and Genomic Alterations Related to Progression

Circulating tumor cells (CTCs) are promising biomarkers for prognosis, therapeutic response prediction, and treatment monitoring in cancer patients. Despite its epithelial origin, renal cell carcinoma (RCC) shows low expression of epithelial markers hindering CTC-enrichment approaches exploiting epithelial cell surface proteins. In 21 blood samples serially collected from 10 patients with metastatic RCC entering the TARIBO trial, we overcame this limitation using the marker-independent Parsortix™ approach for CTC-enrichment coupled with positive and negative selection with the DEPArray™ with single cell recovery and analysis for copy number alterations (CNA) by next generation sequencing NGS. Two CTC subpopulations were identified: epithelial CTC (eCTC) and non-conventional CTC (ncCTC) lacking epithelial and leukocyte markers. With a threshold ≥1CTC/10 mL of blood, the positivity rates were 28% for eCTC, 62% for ncCTCs, and 71% considering both CTC types. In two patients with detectable eCTCs at baseline, progression free survival was less than 5 months. In an index case, hierarchical structure by translational oncology (TRONCO) identified three clones among 14 CTCs collected at progression and at baseline, each containing cells with a 9p21.3loss, a well-known metastasis driving subclonal alteration. CTCs detection in RCC can be increased by marker-independent approaches, and CTC molecular characterization can allow detection of subclonal events possibly related to tumor progression.

Liquid Biopsies to Select Patients for Perioperative Chemotherapy in Muscle-invasive Bladder Cancer: A Systematic Review

CONTEXT

Neoadjuvant chemotherapy (NAC) is considered the standard treatment for muscle-invasive bladder cancer (MIBC). However, its overall survival benefit is limited and toxicity is significant; hence, NAC has not been adopted universally.

OBJECTIVE

To systematically evaluate whether biomarkers can guide the administration of perioperative chemotherapy in MIBC patients.

EVIDENCE ACQUISITION

A systematic search of the PubMed database was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). In total, 215 papers were screened and 22 were selected to assess the potential clinical value of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) in selecting MIBC patients for perioperative chemotherapy.

EVIDENCE SYNTHESIS

We found that the presence of one or more CTCs before radical cystectomy, as determined by the CellSearch technique, is a robust marker for poor recurrence-free and overall survival. Consequently, whether NAC can be withheld in patients without the presence of CTCs is a subject of ongoing investigation. Studies investigating various approaches to detect cfDNA showed that cfDNA is present in the blood of MIBC patients, but varying results on its prognostic value have been reported. Successful cfDNA-based approaches are likely to encompass at least a multitude of genes using next-generation sequencing, as there are generally few hotspot somatic mutations in MIBC.

CONCLUSIONS

Liquid biopsies hold promise in selecting MIBC patients for perioperative chemotherapy, but instead of more proof-of-principle studies, prospective studies investigating true clinical applicability for treatment decision making are urgently needed.

PATIENT SUMMARY

Liquid biopsies appear to be a promising tool to guide the administration of chemotherapy in patients with muscle-invasive bladder cancer; however, the optimal way to implement these remains to be determined.

Expression Profiling of Circulating Tumor Cells in Pancreatic Ductal Adenocarcinoma Patients: Biomarkers Predicting Overall Survival

The interest in liquid biopsy is growing because it could represent a non-invasive prognostic or predictive tool for clinical outcome in patients with pancreatic ductal adenocarcinoma (PDAC), an aggressive and lethal disease. In this pilot study, circulating tumor cells (CTCs), CD16 positive atypical CTCs, and CTC clusters were captured and characterized in the blood of patients with PDAC before and after palliative first line chemotherapy by ScreenCell device, immunohistochemistry, and confocal microscopy analysis. Gene profiles were performed by digital droplet PCR in isolated CTCs, five primary PDAC tissues, and three different batches of RNA from normal human pancreatic tissue. Welsh's t-test, Kaplan-Meier survival, and Univariate Cox regression analyses have been performed. Statistical analysis revealed that the presence of high CTC number in blood is a prognostic factor for poor overall survival and progression free survival in advanced PDAC patients, before and after first line chemotherapy. Furthermore, untreated PDAC patients with CTCs, characterized by high ALCAM, POU5F1B, and SMO mRNAs expression, have shorter progression free survival and overall survival compared with patients expressing the same biomarkers at low levels. Finally, high SHH mRNA levels are negatively associated to progression free survival, whereas high vimentin mRNA levels are correlated with the most favorable prognosis. By hierarchical clustering and correlation index analysis, two cluster gene signatures were identified in CTCs: the first, with high expression of VEGFA, NOTCH1, EPCAM, IHH, is the signature of PDAC patients before chemotherapy, whereas the second, with an enrichment in the expression of CD44, ALCAM, and POU5F1B stemness and pluripotency genes, is reported after palliative chemotherapy. Overall our data support the clinic value of the identification of CTC's specific biomarkers to improve the prognosis and the therapy in advanced PDAC patients.

TARIBO trial: targeted therapy with or without nephrectomy in metastatic renal cell carcinoma: liquid biopsy for biomarkers discovery

Purpose:

Two randomized trials in the cytokine era showed that cytoreductive nephrectomy (CN) had a role in metastatic renal cell carcinoma (mRCC), increasing life expectancy. The survival benefit of tyrosine kinase inhibitors (TKIs), including first-line sunitinib and pazopanib, in mRCC has been demonstrated, but the majority of patients enrolled in the pivotal phase III studies had undergone nephrectomy. Therefore it is unknown if similar survival benefit with targeted agents could be achieved without CN. We hypothesize that in these patients CN could increase overall survival (OS) in comparison to targeted therapy without CN. We also will investigate mechanisms of primary and secondary resistance to TKIs in patients with mRCC and identify prognostic or predictive biomarkers.

Methods:

This is a randomized, open-label, controlled, multicenter phase 3 study comparing sunitinib or pazopanib vs CN followed by sunitinib or pazopanib as first-line therapy for patients with mRCC who have not received surgery and prior systemic treatment for metastatic disease. We will identify 270 patients eligible for randomization. The planned treatment duration per patient will be until progressive disease is observed. Secondary endpoints are the evaluation of progression-free survival (PFS) and response rate and the assessment of the safety profile. Exploratory objectives include the evaluation of circulating tumor cells and circulating tumor DNA and correlation with response/resistance to treatment.

Results:

The study is enrolling patients.

Conclusions:

The use of CN in addition to targeted therapy in patients with renal cell carcinoma with synchronous metastases could lead to a significant improvement in OS and PFS.

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

CONTEXT

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

OBJECTIVE

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSION

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