Study Of Circulating Tumor Cells Research Articles

Circulating tumor cells: clinical validity and utility.

Circulating tumor cells (CTCs) are rare tumor cells and have been investigated as diagnostic, prognostic and predictive biomarkers in many types of cancer. Although CTCs are not currently used in clinical practice, CTC studies have accumulated a high level of clinical validity, especially in breast, lung, prostate and colorectal cancers. In this review, we present an overview of the current clinical validity of CTCs in metastatic and non-metastatic disease, and the main concepts and studies investigating the clinical utility of CTCs. In particular, this review will focus on breast, lung, colorectal and prostate cancer. Three major topics concerning the clinical utility of CTC are discussed-(1) treatment based on CTCs used as liquid biopsy, (2) treatment based on CTC count or CTC variations, and (3) treatment based on CTC biomarker expression. A summary of published or ongoing phase II and III trials is also presented.

Detection of circulating tumor cells (CTC) using a non-EpCAM-based, high-definition, single-cell assay in advanced hepatocellular carcinoma (HCC) for patients enrolled on phase I and II trials of sorafenib plus temsirolimus.

311 Background: Noninvasive biomarkers are needed for diagnosis, prognosis, and molecular profiling of HCC due to scarcity of tumor tissue and heterogeneous tumor biology. CTC are detectable in metastatic HCC using methods which enrich for expression of the cell adhesion molecule, EpCAM. Because a subset of HCC does not express EpCAM, however, non-EpCAM enrichment methods are needed for CTC studies in HCC. Methods: This CTC cohort was derived from patients enrolled on multicenter phase 1 and 2 trials of the combination of sorafenib plus temsirolimus in advanced HCC (NCT01008917, NCT01687673) with approval and funding from the National Comprehensive Cancer Network (NCCN) Oncology Research Program. Eligibility required histologic diagnosis of incurable HCC with no prior systemic therapy. All patients in the cohort were treated at the recommended phase 2 dose of sorafenib 200 mg PO BID and temsirolimus 10 mg IV weekly. Whole blood samples were collected at baseline and on treatment. CTC were enumerated and analyzed cytomorphologically using a high-definition, single cell assay without EpCAM enrichment and blinded to clinical outcomes. Results: The CTC cohort was comprised of 36 patients (phase 1 n = 9, phase 2 n = 27). Characteristics: male 89%; white 64%, Asian/PI 28%, black 6%; HBsAg+ 31%, HCV+ 44%; Child Pugh A 92%, B7 8%; BCLC C 83%; tumor vascular invasion 47%; median AFP 74 ng/mL. Median OS from start of treatment was 392 days (95% CI: 214, 569). CTC ≥ 1/mL were detectable at baseline in 23/36 (64%) overall (95% CI: 47%, 80%), with similar findings in the phase 1 (56%) and phase 2 (67%) subsets. There was no significant relationship between baseline CTC values ≥ 1, 2, or 5/mL and overall survival (OS) on univariate analysis. Analyses of CTC relationship to clinical characteristics and time to progression, changes on treatment, and multivariable analysis for relationship to OS will be presented. Conclusions: CTC were detected in over 60% of patients in this advanced HCC clinical trial cohort using a non-EpCAM, high-definition single cell assay, suggesting future potential for noninvasive molecular profiling of HCC.

Clinical significance of circulating tumor cells in gastric cancer patients.

Circulating tumor cells (CTCs) are rare cancer cells released from tumors into the blood stream that are thought to have a key role in cancer metastasis. Investigation of CTCs is an exciting area of research but remains in its infancy, and the presence of CTCs has been associated with worse prognosis in several major cancer types. Gastric cancer (GC) is a highly lethal malignancy and a serious public health concern in East Asia especially in China. There is an urgent need for identifying new, better prognostic markers to enhance diagnosis and prognosis, facilitate drug development, and to improve the treatment of gastric cancer patients. There are considerable interests in gastric CTCs given their potential use as gastric cancer biomarkers. This review highlights recent advances in studies of gastric CTCs, including the isolation and biological molecular characteristics of gastric CTCs, and their clinical significance.

Biofunctionalized Capillary Flow Channel Platform Integrated with 3D Nanostructured Matrix to Capture Circulating Tumor Cells

Circulating tumor cells (CTCs) from peripheral blood account genetic information for cancer diagnosis and overall disease monitoring. Analysis of “liquid biopsy” holds immense promise as it may lead to new approaches for cancer treatment. The study reports effective and continuous flow microchannel system for isolating CTCs using transferrin conjugated 3D matrix synthesized by crosslinking polyethylene glycol‐Fe3O4 nanostructures for rapid and efficient capturing of CTCs. The platform provides option of using multiple microchannel units in series that can influence higher cell‐capture efficiency due to increasing cell‐substrate contact frequency. CTCs are captured with high efficiency even at low concentration of target cells (~90% at 25 cells per mL blood). Furthermore, the study demonstrates that the cell‐capture performance is influenced by topographic interactions between nanostructure based matrix and cancer cells of interest. In addition, this study demonstrates the “proof of concept” using 3D microchannel system having capacity of simultaneously capturing and permanently eliminating CTCs from peripheral blood samples. Further, the study evaluates clinical samples of colon and breast cancer patients for rapid isolation of CTCs. Conclusively, the present platform demonstrates inordinate capacity for cancer cell sorting, biological studies of CTCs, and cancer metastasis, potentially benefiting the real time liquid biopsy and early prognosis of cancer.

Utilizing Matrigel Transwell Invasion Assay to Detect and Enumerate Circulating Tumor Cells.

Metastasis is the cause of 90% of human cancer deaths. Circulating tumor cells (CTCs) in the peripheral blood and/or lymphatic vessels are cells shed from primary tumors and considered to be precursors of metastasis. Study of CTCs allows the serial monitoring of tumor progression and may provide predictive and prognostic biomarkers in clinic. Current CTC isolation and detection technologies encounter several challenges, including: heterogeneity of CTCs, low cell viability and/or high rate of contamination post-isolation, and the inability to distinguish viable/invasive from nonviable/nonfunctional CTCs, all of which can limit in vitro and in vivo characterization of CTCs. Here, we describe a new method to detect and enumerate of CTCs based on their invasive property.

Biological and Molecular Characterization of Circulating Tumor Cells: A Creative Strategy for Precision Medicine?

Circulating tumor cells (CTCs) are a group of rare cells disseminated from either primary or metastatic tumors into the blood stream. CTCs are considered to be the precursor of cancer metastasis. As a critical component of liquid biopsies, CTCs are a unique tool to understand the formation of metastasis and a valuable source of information on intratumor heterogeneity. Much effort has been invested in technologies for the detection of CTCs because they are rare cells among the vast number of blood cells. Studies in various cancers have repeatedly demonstrated that increased CTC counts prior to or during treatment are significantly associated with poor outcomes. In the new era of precision medicine, the study of CTCs reaches far beyond detection and counting. The rapidly growing field of analytical platforms for rare-cell analysis allows in-depth characterization of CTCs at the bulk cell and single-cell level. Genetic profiling of CTCs may provide an insight into the real-time tumor status, may allow the monitoring and evaluation of treatment response in clinical routine, and may lead to the development of novel therapeutic targets as well.

Affinity Versus Label‐Free Isolation of Circulating Tumor Cells: Who Wins?

The study of circulating tumor cells (CTCs) has been made possible by many technological advances in their isolation. Their isolation has seen many fronts, but each technology brings forth a new set of challenges to overcome. Microfluidics has been a key player in the capture of CTCs and their downstream analysis, with the aim of shedding light into their clinical application in cancer and metastasis. Researchers have taken diverging paths to isolate such cells from blood, ranging from affinity-based isolation targeting surface antigens expressed on CTCs, to label-free isolation taking advantage of the size differences between CTCs and other blood cells. For both major groups, many microfluidic technologies have reported high sensitivity and specificity for capturing CTCs. However, the question remains as to the superiority among these two isolation techniques, specifically to identify different CTC populations. This review highlights the key aspects of affinity and label-free microfluidic CTC technologies, and discusses which of these two would be the highest benefactor for the study of CTCs.

Abstract 3307: Label-free high throughput microfluidic device for the isolation and single cell multiplex gene expression analysis of circulating tumor cells from breast cancer patients

Abstract Introduction and Objective: The metastasis of cancer is preceded by the dissemination of cancer cells from the primary tumor site to remote sites via the blood circulation. The presence of circulating tumor cells (CTCs) in the peripheral blood represents a strong and independent prognostic factor for decreased disease-free and overall survival. Immune-affinity based capture, although being the most commonly used method for the isolation of CTCs, offers low throughput (∼1mL/hr) and have considerably cell loss caused by the heterogeneous expression of biomarkers on CTCs. Various label-free approaches utilizing the physical properties of CTCs have been developed to overcome the limitations, such as micro-filters, microscale laminar vortices, inertial migration of particles, and integrated systems. Here we present an inertial microfluidic-based separation technique for high throughput and label-free isolation of CTCs yielding the highest throughput with high CTC recovery and high blood cell removal among all the label-free technologies. The isolated CTC populations were further analyzed for single cell multiplex gene expression analysis. Methods: The PDMS-made inertial microfluidic device has 637 mm in length with 56 corners, 500 μm in width, and 100 μm in height. The separation of CTCs is driven by two main forces: (i) inertial force that focuses the cells into streamlines, and (ii) drag force from Dean flow that migrates the focused cells to various positions based on size. Device is optimized with MCF-7 and Panc-1 cell line within PBS buffer solution and diluted blood, and is tested in patients with breast cancer on an average of 5 mL of whole blood processed through double devices in series. CTCs isolated were analyzed for tumor specific protein markers and genomic characterization is done using singe cell analysis techniques. Results: Samples are processed through the inertial microfluidic device and CTCs are enriched in second outlet based on size difference between CTCs and blood cells. Device is optimized to operate at an extremely high throughput of 2500 μL/min with high recovery (greater than 90%) and high white blood cells (WBCs) removal (5 log orders). In patient samples, we identified CTCs in 38 of 40 (95%) breast patients with metastatic disease (5.4±4.6 CTC/mL) with low WBC contamination (663±647 WBC/mL). Based on the gene expression, both inter and intra patient heterogeneity of CTCs at the single cell level were discovered among the tested patient samples. Conclusion: The study of CTCs could have a direct impact upon society by presenting novel ways to address one of the major hurdles in cancer research - early detection - and will foster the advancement of science and engineering via the exploration of new druggable targets approaches and the further understanding of the pharmacodynamics. Citation Format: Eric Lin, Lianette Rivera, Shamileh Fouladdel, Hyeun Joong Yoon, Stephanie Guthrie, Jacob Weiner, Yadwinder S. Deol, Evan Keller, Vaibhav Sahai, Diane M. Simeone, Monika L. Burness, Ebrahim Azizi, Max S. Wicha, Sunitha Nagrath. Label-free high throughput microfluidic device for the isolation and single cell multiplex gene expression analysis of circulating tumor cells from breast cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3307.

Single-Cell Analysis of Circulating Tumor Cells as a Window into Tumor Heterogeneity.

Recent advances in microfluidic approaches have enabled the efficient isolation and detailed molecular characterization of circulating tumor cells (CTCs) in the peripheral blood of patients with cancer. Single-cell molecular analyses of CTCs reveal a tremendous degree of intracellular heterogeneity in CTC populations, reflective of heterogeneity across different patients as well as the underlying heterogeneity of tumors within each individual patient. These studies have enabled the identification of heterogeneous drug resistance mechanisms that can coexist in treatment refractory tumors. CTC analyses also enable serial noninvasive monitoring in patients and can capture the emergence of tumor heterogeneity over time, whether due to tumor evolution through genetic instability or through cellular plasticity. The presence and extent of intratumoral heterogeneity as revealed through the study of CTCs have important clinical implications for understanding and predicting the development of treatment resistance in a variety of solid tumors and for formulating appropriate therapeutic strategies in the effective treatment of cancer.

EpCAM based capture detects and recovers circulating tumor cells from all subtypes of breast cancer except claudin-low

The potential utility of circulating tumor cells (CTCs) as liquid biopsies is of great interest. We hypothesized that CTC capture using EpCAM based gating is feasible for most breast cancer subtypes. Cancer cells could be recovered from all intrinsic subtypes of breast cancer with IE/FACS, however, claudin-low cell lines showed very low capture rates compared to the four other groups (p = 0.03). IE/FACS detection of CTC mimic cells was time sensitive, emphasizing controlling for pre-analytic variables in CTC studies. Median fluorescent intensity for flow cytometry and RNA flow cell type characterization were highly correlated, predicting for CTC isolation across molecular subtypes. RNA-Seq of IE/FACS sorted single cell equivalents showed high correlation compared to bulk cell lines, and distinct gene expression signatures compared to PB. Ten cell lines representing all major subtypes of breast cancer were spiked (as CTC mimics) into and recovered from peripheral blood (PB) using immunomagnetic enrichment followed by fluorescence-activated cell sorting (IE/FACS). Flow cytometry and RNA flow were used to quantify the expression of multiple breast cancer related markers of interest. Two different RNA-Seq technologies were used to analyze global gene expression of recovered sorted cells compared to bulk cell lines and PB. EpCAM based IE/FACS detected and captured a portion of spiked cells from each of the 10 cell lines representing all breast cancer subtypes, including basal-like but not claudin-low cancers. The assay allows for the isolation of high quality RNA suitable for accurate RNA-Seq of heterogeneous rare cell populations.

Diversity of assessing circulating tumor cells (CTCs) emphasizes need for standardization: a CTC Guide to design and report trials.

Hematogenous spreading of tumor cells from primary tumors is a crucial step in the cascade to metastasis, the latter being the most limiting factor for patients' survival prognosis. Therefore, circulating tumor cells (CTCs) have become a field of intensive research. However, the process of isolation and identification of CTCs lacks standardization. This article presents an overview of 71 CTC studies reported in PUBMED since 2000 and focusing on colorectal cancer. These studies are evaluated regarding standardization of CTC isolation and identification, marker proteins used, study population and blood sample quality management, clinical performance, and quality measures. Overall, standardization of CTC assessment seems insufficient. Thus, comparability of CTC studies is hampered and results should be interpreted carefully. We here propose a standardized CTC guideline (CTC Guide) to prospectively design and report studies/trials in a harmonized form. Despite the current interstudy heterogeneity, the data indicate that CTC detection is of clinical relevance and CTCs should be considered as a surrogate prognostic marker. Many studies indicate the high potential for CTCs as prognostic markers, e.g., in colorectal cancer treatment. However, standardized, large-scale multicenter validation studies are still needed to pave the way for clinical implementation of CTC detection that could ameliorate individualized medicine regimes.

Feasibility of a workflow for the molecular characterization of single cells by next generation sequencing

The purpose of the study was to explore the feasibility of a protocol for the isolation and molecular characterization of single circulating tumor cells (CTCs) from cancer patients using a single-cell next generation sequencing (NGS) approach.To reach this goal we used as a model an artificial sample obtained by spiking a breast cancer cell line (MDA-MB-231) into the blood of a healthy donor.Tumor cells were enriched and enumerated by CellSearch® and subsequently isolated by DEPArray™ to obtain single or pooled pure samples to be submitted to the analysis of the mutational status of multiple genes involved in cancer.Upon whole genome amplification, samples were analysed by NGS on the Ion Torrent PGM™ system (Life Technologies) using the Ion AmpliSeq™ Cancer Hotspot Panel v2 (Life Technologies), designed to investigate genomic “hot spot” regions of 50 oncogenes and tumor suppressor genes.We successfully sequenced five single cells, a pool of 5 cells and DNA from a cellular pellet of the same cell line with a mean depth of the sequencing reaction ranging from 1581 to 3479 reads.We found 27 sequence variants in 18 genes, 15 of which already reported in the COSMIC or dbSNP databases. We confirmed the presence of two somatic mutations, in the BRAF and TP53 gene, which had been already reported for this cells line, but also found new mutations and single nucleotide polymorphisms. Three variants were common to all the analysed samples, while 18 were present only in a single cell suggesting a high heterogeneity within the same cell line.This paper presents an optimized workflow for the molecular characterization of multiple genes in single cells by NGS. The described pipeline can be easily transferred to the study of single CTCs from oncologic patients.

Abstract 1593: Label-free high throughput microfluidic device for the isolation of circulating tumor cells from breast cancer patients

Abstract Introduction and Objective: A necessary step in distant metastasis is the hematogenous dissemination of cancer cells from the primary tumor site to remote sites. The presence of circulating tumor cells (CTCs) in the peripheral blood represents a strong and independent prognostic factor for decreased disease-free and overall survival in many solid malignancies. Immune-affinity based capture is the most commonly used method for the isolation of CTCs which utilizes antibodies to capture tumor cells expressing specific proteins. However, immune-affinity based approaches offer low throughput (∼1mL/hr) and considerable cell loss (∼20-40%) resulting from heterogeneous expression of biomarkers on CTCs. Various label-free approaches utilizing physical properties of CTCs have been developed to overcome the limitations of immune-affinity based isolation techniques, including micro-filters, microscale laminar vortices, inertial migration of particles, and integrated systems. Here we present an inertial microfluidic-based separation technique for high throughput and label-free isolation of CTCs that yields the highest throughput with high CTC recovery and high blood cell removal among all the label-free technologies. Methods: The PDMS-made microfluidic device has 637 mm in length with 56 corners, 500 μm in width, and 100 μm in height. The separation is driven by two main forces: (i) inertial force that focuses the cells into streamlines, and (ii) drag force from Dean flow that migrates the focused cells to various positions based on size. The device was optimized with MCF-7 and Panc-1 cell lines spiked into PBS buffer and also diluted blood. It was then tested on 10 mL blood samples from patients with metastatic breast cancer. The separated cells were cytospun and stained to identify CTCs as cytokeratin positive, DAPI positive, CD45 negative cells. Results: Samples were processed through the inertial microfluidic device that enriches CTCs in the second outlet based on size difference between CTCs and blood cells. The device was optimized to operate at an extremely high throughput of 2500 μL/min with high recovery (92% for both spiked samples of MCF-7 and PANC-1 cell lines) and high white blood cells (WBCs) removal (91%). To determine the efficiency of capture of rare cell populations, healthy donor blood samples were spiked with MCF-7/GFP at 100 cells and 95% recovery was obtained. In patient samples, we identified CTCs in 24 of 27 (89%) breast patients with metastatic disease (4.3±4.8 CTCs/mL) with low WBCs contamination (465±473 WBCs/mL). Conclusion: The study of CTCs could have a direct impact upon patient care by presenting a novel CTC isolation method. This technology may be applicable to early detection, and also for monitoring response to treatment. Our approach is superior to current strategies because it is independent of cell surface markers, which may be varied in tumor cells, and may exclude cancer stem cells. Citation Format: Eric Lin, Lianette Rivera, Hyeun Joong Yoon, Shamileh Fouladdel, Jacob Wieger, Stephanie Guthrie, Yadwinder S. Deol, Shawn G. Clouthier, Tahra K. Luther, Diane M. Simeone, Monika L. Burness, Ebrahim Azizi, Max S. Wicha, Sunitha Nagrath. Label-free high throughput microfluidic device for the isolation of circulating tumor cells from breast cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1593. doi:10.1158/1538-7445.AM2015-1593

The biology of circulating tumor cells.

Metastasis is a biologically complex process consisting of numerous stochastic events which may tremendously differ across various cancer types. Circulating tumor cells (CTCs) are cells that are shed from primary tumors and metastatic deposits into the blood stream. CTCs bear a tremendous potential to improve our understanding of steps involved in the metastatic cascade, starting from intravasation of tumor cells into the circulation until the formation of clinically detectable metastasis. These efforts were propelled by novel high-resolution approaches to dissect the genomes and transcriptomes of CTCs. Furthermore, capturing of viable CTCs has paved the way for innovative culturing technologies to study fundamental characteristics of CTCs such as invasiveness, their kinetics and responses to selection barriers, such as given therapies. Hence the study of CTCs is not only instrumental as a basic research tool, but also allows the serial monitoring of tumor genotypes and may therefore provide predictive and prognostic biomarkers for clinicians. Here, we review how CTCs have contributed to significant insights into the metastatic process and how they may be utilized in clinical practice.

A physical sciences network characterization of circulating tumor cell aggregate transport

Circulating tumor cells (CTC) have been implicated in the hematogenous spread of cancer. To investigate the fluid phase of cancer from a physical sciences perspective, the multi-institutional Physical Sciences-Oncology Center (PS-OC) Network performed multidisciplinary biophysical studies of single CTC and CTC aggregates from a patient with breast cancer. CTCs, ranging from single cells to aggregates comprised of 2-5 cells, were isolated using the high-definition CTC assay and biophysically profiled using quantitative phase microscopy. Single CTCs and aggregates were then modeled in an in vitro system comprised of multiple breast cancer cell lines and microfluidic devices used to model E-selectin mediated rolling in the vasculature. Using a numerical model coupling elastic collisions between red blood cells and CTCs, the dependence of CTC vascular margination on single CTCs and CTC aggregate morphology and stiffness was interrogated. These results provide a multifaceted characterization of single CTC and CTC aggregate dynamics in the vasculature and illustrate a framework to integrate clinical, biophysical, and mathematical approaches to enhance our understanding of the fluid phase of cancer.

Circulating Tumor Cells: A Window to Understand Cancer Metastasis, Monitor and Fight Against Cancers

Metastases are the major culprits behind most cancer-related death and the central challenge to the eradication of a malignancy. Circulating tumor cells (CTCs) have the potential to help us understand how metastases form, to be utilized for cancer diagnosis and treatment selection and even to be targeted for cancer treatment. Many advances have been made regarding the isolation of these rare cells. However, several challenges and limitations in CTC analysis still exist. Multiple color immunofluorescence, genetic analysis (e.g. Fluorescence in situ Hybridization, microarray and next generation sequencing) and CTC culture will be effective tools to study CTCs and provide information on metastatic mechanism and clinical implication. In this review, we discuss the importance of CTC study in understanding cancer metastasis and their potential clinical application as biomarkers to predict cancer progression and treatment response, as well as the current situation for CTC isolation and analysis.

Orthotopic mouse models of tumor metastasis expressing fluorescent reporters produce imageable circulating tumor cells.

Circulating tumor cells (CTC) are of high importance, since they are potential metastatic precursors and are readily available for prognostic analysis and treatment testing. In this review, we demonstrate the great power that green fluorescent protein (GFP) labeling and orthotopic mouse models of cancer confer to the study of CTCs for isolation and characterization, including metastatic testing in mice and the chick embryo as well as drug response testing in vitro. We also describe a facile method to label patient CTCs ex vivo using a telomerase-expressing GFP-containing adenovirus that will allow the CTC studies described in this review to be translated clinically.

Abstract 3477: Continuous isolation, labeling and collection of viable CTCs using an integrated microfluidic device

Abstract The concept of studying tumor-derived circulating tumor cells (CTCs) from a simple blood-draw of a patient, has acquired significant attention in recent years. This relatively non-invasive approach opens many avenues in understanding and monitoring quite a number of cancers where correlations have since been made with CTCs and patient survival as well as patient response to therapeutics. Additionally, studies geared towards identifying genetic markers as well as gene profiling of CTCs are ongoing in efforts to develop early screening markers as well as gain a more holistic understanding of the various forms of the disease. Moreover, the concept of personalized medicine in treating several types of cancer is deemed indispensable due to the highly heterogeneous nature of the disease. Extensive studies involving genetic material of CTCs are expected to considerably develop effective therapeutics that are tailored to meet each patient's need. However, several challenges need to be overcome in order to harness the wealth of information that can be gained from CTC studies, such as the rarity of such cells among other blood cells, where CTCs occur as rarely as 1 to 1 million among other mononuclear blood cells. In this vein we discuss the development of an integrated, continuous microfluidic device designed to isolate and label CTCs disseminated from cancer tumors. The 3-part device initially exploits the size disparity of the majority of CTCs with other blood cells and couples this with the use of size-based inertial forces to presort CTCs from whole blood at 1.2mL/min. The CTC-rich fluid stream is then mixed passively, on-chip, with EpCAM coated micro-beads which allows the cells and beads to mix at the micron length scale. This is followed by a brief period of incubation which allows cells to be sufficiently labeled, where the majority of cells have experienced at least two-thirds magnetic bead coverage using this mixing-incubation approach. Thereafter on-chip magnetic sorting of CTCs from any remaining blood cells is achieved by application of an external magnet along the magnetic sorter of the integrated device. Cells with as little as one-third bead coverage experience magnetic deflection to the CTC collection stream. To identify CTCs, cells were stained positively for DAPI and CK-19, and CD45 was used to distinguish leukocytes. We demonstrate that the isolated CTCs are not only viable but that the range of WBC decontamination is the lowest yet reported in literature. Based on PANC-1 cell-line experiments with the device, an 80% recovery rate of cancer cells from other blood cells was consistently achieved. Testing of metastatic patient samples with the device has yielded high counts of CTCs, coupled with high purity rates. We believe that the use of this system in characterizing CTCs and studying cancer will contribute to understanding this aggressive disease in a non-invasive, efficient manner. Citation Format: Rhonda M. Jack, Meggie MG Grafton, Robert A. Cieslak, Denise C. Jue, Cathy Griffith, Danika Rodrigues, Sunitha Nagrath, Diane Simeone. Continuous isolation, labeling and collection of viable CTCs using an integrated microfluidic device. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3477. doi:10.1158/1538-7445.AM2014-3477

Abstract 3070: Capture, isolation, and mutational analysis of single pancreatic circulating tumor cells using NanoVelcro technology

Abstract Introduction: Circulating tumor cells (CTCs) have been developed as a biomarker in several cancers, but not in pancreatic cancer (PDAC). The available clinical technology for CTC study, CellSearch, suffers from limited ability to perform molecular analysis. We sought to evaluate a novel microfluidic NanoVelcro technology coupled to laser micro-dissection (LMD), for CTC capture and single cell analysis of KRAS mutations to confirm tumor origin of captured CTCs. Methods: NanoVelcro utilizes a nano-spun polymer fiber, modified with streptavidin, to capture CTCs using biotinylated antibodies. The system was optimized with the CFPAC-1 (EpCAM+, KRAS G12 to V) cell line spiked into healthy donor blood. Patient samples were collected from 2 mL peripheral venous blood and run at the optimized flow rate of 1mL/hr. CTCs were defined by size (≥ 10 µm) and immuno-staining pattern (DAPI+/CK+/CD45-). Using LMD, single cells were isolated and subjected to whole genome amplification followed by PCR of KRAS exon 1 and subsequent Sanger Sequencing. Results: The NanoVelcro system allowed for detection of mutant KRAS in isolated CFPAC-1 cells. 6 CTCs were then isolated from a known KRAS G12 to V mutant patient and 3/6 (50.0%) captured CTCs were found to have KRAS G12 to V mutations while normal WBCs from the same patient contained wild-type KRAS. Conclusions: The microfluidic NanoVelcro technology demonstrated capture of pancreatic CTCs and may prove useful in the development of CTCs as a biomarker in PDAC. Application of LMD enabled single cell KRAS mutational analysis confirming cancer origin of isolated CTCs and supporting our current PDAC CTC identification criteria based on immuno-staining. This promising technology, combined with LMD, opens the door for molecular characterization of CTCs, thus providing insight into the biology of metastasis while potentially revealing molecular targets for therapeutics. Citation Format: Jacob S. Ankeny, Shuang Hou, Millicent Lin, Matthew Frias, Hank OuYang, Min Song, Matthew M. Rochefort, Mark D. Girgis, Hsian-Rong Tseng, James S. Tomlinson. Capture, isolation, and mutational analysis of single pancreatic circulating tumor cells using NanoVelcro technology. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3070. doi:10.1158/1538-7445.AM2014-3070

Nanotechnology for the detection and kill of circulating tumor cells.

Circulating tumor cells (CTCs) represent a surrogate biomarker of hematogenous metastases and thus could be considered as a ‘liquid biopsy’ which reveals metastasis in action. But it is absolutely a challenge to detect CTCs due to their extreme rarity. At present, the most common principle is to take advantage of the epithelial surface markers of CTCs which attach to a specific antibody. Antibody-magnetic nanobeads combine with the epithelial surface markers, and then the compound is processed by washing, separation, and detection. However, a proportion of CTC antigen expressions are down-regulated or lost in the process of epithelial-mesenchymal transition (EMT), and thus, this part of CTCs cannot be detected by classical detection methods such as CellSearch. To resolve this problem, some multiple-marker CTC detections have been developed rapidly. Additionally, nanotechnology is a promising approach to kill CTCs with high efficiency. Implantable nanotubes coated with apoptosis-promoting molecules improve the disease-free survival and overall survival. The review introduces some novel CTC detection techniques and therapeutic methods by virtue of nanotechnology to provide a better knowledge of the progress about CTC study.