Isolation Of Circulating Tumor Cells Research Articles

Abstract 6706: Co-culture of circulating tumor cells (CTCs)-derived 3D organoids and autologous cytotoxic CD8+ T cells: A new functional precision oncology platform

Abstract Greater than 10 million patients succumb to cancer each year. Cancer metastasis is responsible for more than 90% of all cancer-associated deaths due to treatment resistance and increased tumor burden. As a seed for metastases, circulating tumor cells (CTCs) present a new dimension and horizon for clinical doctors in diagnosis, prognosis prediction, treatment monitoring, disease mechanism, and drug development. CTCs could gradually replace tissue biopsies which are painful and may be difficult to obtain depending on tumor location. CTC isolation is feasible after minimally invasive liquid biopsy and provides the basis for a multitude of ex vivo and in vivo studies including establishment of CTCs-derived 2D and 3D cultures. Organoids are miniscule models of tissues that grow in a 3D semisolid extracellular matrix medium with specific growth factors supplied. CTCs-derived 3D organoids play a vital role in precision oncology because they can preserve tumor heterogeneity, imitate the tumor microenvironment (TME), mimic cancer hypoxia in the TME, and maintain cancer and metastasis phenotypes. Cytotoxic CD8+ T cells are the most powerful effectors in the anticancer immune response. We hypothesized that co-culture of CTCs-derived 3D organoids and autologous cytotoxic CD8+ T cells could maximize patient-relevance of laboratory assessment of cancer-treatment immune-system interactions to facilitate precision oncology practice. TellBio’s novel TellDx CTC technology allows for isolation of viable and intact CTCs in liquid biopsies, regardless of cancer type. Unlabeled CTCs were cultured in growth factor reduced Matrigel with organoid culture WENRAS medium. Magnetic beads labeled white blood cells (WBCs) were cultured with T cell culture medium - WBCs and magnetic beads usually separate in three days - cytotoxic CD8+ T cells were isolated with the EasySep™ Human CD8+ T Cell Isolation Kit. CTCs-derived 3D organoids and autologous cytotoxic CD8+ T cells were co-cultured with or without different drug treatments - cytotoxicity was measured with CellTiterGlo® 3D Cell Viability Assay and imaging, and further mechanistic studies were feasible. Our co-culture platform enables us to utilize a patient's peripheral blood or pleural effusions to create a patient-specific, in vivo-like TME and immune microenvironment to model and assess ex vivo responses to investigational and FDA-cleared cancer therapies, and potentially provide oncologists with insights to improve clinical outcomes. Citation Format: Lanlan Zhou, Leiqing Zhang, Lindsey Carlsen, Kelsey E. Huntington, Vida Tajiknia, Andrew George, Arielle De La Cruz, Arunasalam Navaraj, Praveen Srinivasan, Maximilian Schwermann, Benedito A. Carneiro, Wafik S. El-Deiry. Co-culture of circulating tumor cells (CTCs)-derived 3D organoids and autologous cytotoxic CD8+ T cells: A new functional precision oncology platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6706.

Abstract 5592: Expansion and characterization on ALK positive NSCLC circulating tumor cells isolated using a size based inertial microfluidic Labyrinth device

Abstract Introduction Lung cancer (LC) is the leading cause of cancer deaths. 85% of LC are non-small cell lung cancer (NSCLC). Fusions involving anaplastic lymphoma kinase (ALK) are oncogenic drivers in ~ 7% of NSCLC. Previous studies have shown that drug resistance develops within ~2 years after ALK tyrosine kinase inhibitor targeted therapy. Due to resistance mechanisms and the biological heterogeneity that evolves over the treatment of ALK+ NSCLC, it is important to monitor and study those dynamic changes through the clinical treatment course to understand cancer progression. Circulating tumor cells (CTCs) are rare cells, shed from cancer lesions into the bloodstream. They can be isolated from a patient's peripheral blood sample (~20ml) to enable study of tumor characteristics at multiple time points. They are promising biomarkers that not only offer phenotypic and genotypic information, but also present a potential to expand into patient derived ex vivo tumor models. In this study, we use a high throughput label-free microfluidic device, Labyrinth, developed in the Nagrath lab for cell size based CTC enrichment, followed by expansion of CTCs in organoid models, further molecular characterization, and growth in patient-derived xenograft (PDX) models. Methods Blood samples were collected from patients (n=22), three with known ALK status. CTC isolation was performed using Labyrinth at 2.0 mL/min. A part of the isolated CTCs were immunofluorescently stained for pan cytokeratin (pan CK), CD45, DAPI, epithelial cell adhesion molecule (EpCAM), and vimentin markers for enumeration. Others were processed for expansion in ultralow attachment plates with three types of organoid culture media. The rest of the CTCs were used for molecular characterizations. Growth curves were produced on expanded samples on Day 0, 7, 14, and 21 in different culture conditions. A live/dead assay and in situ hybridization (FISH) were also performed. On Day 7, selected samples were injected into NSG™ mice. Bulk RNA sequencing was conducted on the original tumor, Day 0 and 7 CTCs, and PDX samples. Results The median CTC concentration in this cohort (n=22) was 316.2 CTCs/ml of blood. Isolated CTCs from ALK+ NSCLC patients showed ALK fusions by FISH. We observed that the number of ALK CTCs was reduced over time consistent with decreased tumor size in CT scans. There were significant differences (p<0.05) for vimentin positive CTCs compared to the other three types of CTCs, which indicated a higher prevalence of a mesenchymal state of NSCLC CTCs. One of the two samples successfully developed into PDX after two months. In summary, we demonstrated a successful workflow to enrich and expand CTCs from ALK+ NSCLC patients. The expanded CTCs can be further characterized and can generate tumors in PDX models. Citation Format: Yuru Chen, Shamileh Fouladdel, Harrison Ball, Xu Cheng, Liwei Bao, Habib Serhan, Albert Liu, Bryce Vandenburg, Laura Goo, Nathan Merrill, Aaron Udager, Angel Qin, Sofia D. Merajver, Sunitha Nagrath. Expansion and characterization on ALK positive NSCLC circulating tumor cells isolated using a size based inertial microfluidic Labyrinth device. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5592.

Abstract 6605: Automated isolation and identification of circulating rare cells from blood samples using a label-free rare cell isolation platform - the Genesis System with Celselect Slide technology

Abstract Introduction: Isolation and identification of circulating tumor cells (CTCs) offers a promising non-invasive diagnostic tool for cancer research, but significant technical hurdles have made practical application challenging. Recent studies have shown that CTCs undergo cellular changes, such as an epithelial-mesenchymal transition (EMT), with disease progression and metastasis, implying the heterogeneity of the tumor cell population in circulation. Systems for CTC isolation are often limited by a requirement for epithelial markers or separate systems for identification of CTCs. As such, an automated platform that successfully isolates both epithelial and mesenchymal cells and enables identification of cells is necessary for successful study of CTCs. The Genesis System from Bio-Rad™ Laboratories, Inc. isolates rare CTCs based on size and deformability. It also enables users to identify isolated cells through use of an on-slide immunofluorescence (IF) staining workflow, which minimizes sample manipulation and potential sample loss. Methods: In order to achieve high-throughput label-free CTC isolation, the Genesis System uses Celselect Slides™. Each slide contains 56,400 individual microchambers to capture CTCs while maintaining viability. This Celselect Slide technology can be used for either enrichment or enumeration protocols. For this study, enumeration protocols were performed to capture and identify CTCs using on-slide IF staining. Enrichment protocols were utilized to capture, enrich, and retrieve CTCs for downstream applications. The performance was evaluated using a breast cancer cell line, MCF-7, spiked into whole blood from healthy donors. Results: The slide isolated 83.95 ± 10.25% of spiked cancer cells in blood samples at a concentration of 10-250 cells/ml. During the CTC enrichment procedure, 99.92% of blood cells were eliminated. Afterwards, 70% of the isolated CTCs were successfully released from the slide and over 92% of the released cells remained viable. Discussion and Conclusion: We present a fully automated platform to isolate and identify CTCs using on-slide immunofluorescence staining, which minimizes inevitable cell loss during the workflow. Captured cells can be retrieved for downstream applications to facilitate discovery of unknown CTC functions and their clinical relevance in cancer research. The wide range of possible downstream applications include Droplet Digital™ PCR, quantitative PCR, western blot assays, bulk/single-cell genomics, cell culture, fluorescence in situ hybridization, and RNA-Seq. Additionally, the design of the system is amenable to other biofluids which may be utilized for liquid biopsies. The Genesis System with Celselect Slide technology offers a powerful diagnostic tool to monitor disease progression and personalized treatment. Citation Format: Yoon-Tae Kang, Errile Pusod, Ally Crudgington, Abiodun Bodunrin, Nick Bosio, Susana Chan, David Coe, Michelle Racey. Automated isolation and identification of circulating rare cells from blood samples using a label-free rare cell isolation platform - the Genesis System with Celselect Slide technology. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6605.

Abstract 1040: Evaluation of blood collection tube’s performance for analysis of liquid biopsies by flow and mass cytometry

Abstract The detection of liquid biopsies, including circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) have demonstrated promise as non-invasive assays for monitoring response to therapy for patients with cancer. While ctDNA cannot predict transcriptomic and proteomic changes in response to therapy, we can measure direct cell surface antigen and gene expression changes in CTCs. In pediatric settings, blood samples are often collected from multi-institutional trials. Therefore, to translate liquid biopsies into routine practice, it is important to explore variables most likely to impact the functionality of CTCs including time to process the sample, prospective cryopreservation, blood collection tube and fixative reagents. Cell stabilizer tubes such as Streck Cell-Free DNA, CellSave, CellRescue, or PAXgene ccfDNA have been designed to prevent cell lysis and release of genomic DNA into the plasma, often observed in standard EDTA tubes. In pediatrics, we are often limited by the volume of blood we can draw for research. To this end, we have established an innovative pipeline to collect ctDNA, CTCs, and matched germline DNA from a single blood sample. Blood samples were processed for plasma extraction and CTC isolation after 4h, 24h, and 48h. We isolated rare CTCs from whole blood by combining peripheral blood cell depletion with antigen-based CTC identification. We then evaluated CTC recovery rate and cell membrane integrity (cell-membrane permeabilization) across all blood collection tubes by flow or mass cytometry. Additionally, we integrated whole transcriptome analysis of RNA transcripts in individually sorted CTCs. In this study, we detected similar levels of cell-free DNA, germline DNA and ctDNA in healthy donors and patient samples collected in the DNA stabilizer tubes up to 48h after blood collection. Surprisingly, frequent clotting was observed in the cell layer of samples collected in PAXgene tubes only 24h after blood collection, preventing further analysis of CTC quality in these tubes. At 4h, EDTA tubes and stabilizer tubes seem to perform similarly in preserving CTC integrity. However, at later timepoints, CTC recovery rate, RNA quality and cell membrane integrity were significantly higher in CellRescue tubes. Finally, we showed that CTC count, and RNA quality were slightly lower in patient samples enumerated after cryopreservation compared to the paired-samples processed the same day in both EDTA and cell-stabilizing tubes. In conclusion, we validated the CellRescue tubes as the best candidate to reduce cell lysis and protect against cell membrane permeabilization and mRNA degradation for up to 48 hours, allowing sample collection from multi-institutional studies. To the best of our knowledge, this study is the first to compare the key steps in handling blood samples and how this affects transcriptomic-based assay performance. Citation Format: Anne-Florence Blandin, Sarah Finstuen-Magro, Samuel Abbou, Kelly Klega, Alejandra E. Aguilar, Mohammad Tanhaemami, Maria Ana Isabel C. De Los Santos, Joadly Duplan, Brian Crompton. Evaluation of blood collection tube’s performance for analysis of liquid biopsies by flow and mass cytometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1040.

Abstract 4185: Inclusive basic and advanced translational laboratory research competencies for research in cancer biology and therapeutics

Abstract Our Laboratory was established in 1994 at Univ. of Pennsylvania. Lab members demonstrated initial competencies by performing cell culture, western blots, immunofluorescence, and flow cytometry showing induction of p53/p21(WAF1) in cells treated with chemotherapy. Years later, our Laboratory of Translational Oncology & Experimental Cancer Therapeutics moved to Penn State Univ., Fox Chase Cancer Center/Temple Univ. and then Brown Univ. By 2020, with desire for inclusiveness (everyone succeeds), scientific rigor/reproducibility mandated by NIH, and as a training and mentoring activity (lab scientists/trainees/students mentoring others at High School level and beyond), we established a process for onboarding and training new cancer researchers. By Fall of 2022, there were 17 current Brown University undergraduate students (10 receiving research credit and 7 not receiving credit), HS students, 7 graduate students (PhD, masters, MD/PhD), and 6 medical students working with collaborating faculty at our laboratory at Brown’s Legorreta Cancer Center. After completion of biosafety training, and required trainings such as by IACUC, new lab members complete basic competencies in cell culture, cell viability, and western blot analysis that include technical, presentation quality output, and quantitative/statistical rigor to satisfy current standards for journal publication. For cell culture this includes pathogen free conditions, authentication, attention to details of routine procedures, documentation of morphology, freezing, thawing, passaging, seeding density, and managing cell populations to not run out of cells. Cell viability assessment includes attention to culture conditions, synergy analysis, data robustness, and presentation, and for western blots attention to quality of blots, protein quantification, loading, labeling, antibody specificity and sensitivity controls, presentation at 2022 standards, conventions for splicing, and issues with reproducibility including biological replicates, and generalizability. Additional and advanced competencies include RT-PCR, long-term colony assays, 3-D cultures (spheroids, organoids), transfection (overexpression, knockdown, CRISPR), co-culture and triculture with immune cells and fibroblasts, cytokine profiling, in vivo studies, in vivo imaging, immunohistochemistry, flow cytometric analysis, single cell techniques, viral infection, circulating tumor cell isolation, blood immune and cytokine analysis, and work with transgenic organoids and inducible cancer predisposing alleles. Modeling the tumor microenvironment, relevance to human cancer and translational directions are emphasized. Shared online lab resources, protocols, practices, videos, and manuscripts are available for lab members. The framework herein may be of interest to others involved in similar training programs. Citation Format: Wafik S. El-Deiry, Andrew George, Francesca Di Cristofano, Praveen Srinivasan, Lindsey Carlsen, Kelsey E. Huntington, Arielle De La Cruz, Leiqing Zhang, Marina Hahn, Shuai Zhao, Attila Seyhan, Bradley D. DeNardo, Aaron W. Maxwell, Dae Hee Kim, Alex Raufi, Hina Khan, Stephanie L. Graff, Don S. Dizon, Christopher Azzoli, Abbas E. Abbas, Roxanne Wood, Rishi R. Lulla, Howard P. Safran, Benedito A. Carneiro, Arunasalam Navaraj, Xiaobing Tian, Shengliang Zhang, Lanlan Zhou. Inclusive basic and advanced translational laboratory research competencies for research in cancer biology and therapeutics. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4185.

A narrative review of diagnostic and therapeutic potential of isolation ofcirculating tumor cells

Background. The spread of metastasis (metastasizing) is the leading cause of cancerrelated death, and the ability of tumor cells to migrate through surrounding tissue and to intravasate into blood or lymphatic vessels is an important interim step in the transition from localized to systemic disease. In 5% to 10% of all cases of advanced cancer, metastatic lesions are detected before the primary tumor. The cellular basis of metastasis is the ability of tumor cells to leave the primary focus and to enter systemic circulation, i.e., the so-called circulating tumor cells. Early detection of these cells is of high diagnostic value and may serve as a specific prognostic marker of treatment effectiveness. Therefore, it is a rationale for review and analysis of state-of-the-art information on approaches to quantitative and qualitative analysis of circulating tumor cells. Aim – to characterize current diagnostic and therapeutic potential of isolation of circulating tumor cells. Materials and methods. Literature search was performed with the following keywords: circulating tumor cells, metastases, migration and invasion, technologies of circulating tumor cells isolation, receptor-ligand interactions of circulating tumor cells. On the second stage, article abstracts were screened and non-relevant publications were excluded. On the third stage, full-text articles were assessed for meeting the inclusion criteria for the list of references and for the relevance of studies. Results and discussion. As compared with conventional biopsy, the study of circulating tumor cells is a relatively inexpensive and non-invasive method, so it can be repeated many times during therapy, which makes this technique a powerful tool for monitoring the development of cancer. Given the low number of circulating tumor cells in whole peripheral blood, their isolation is a decisive step for further analysis. Monitoring the content of circulating tumor cells during therapy is a tool that allows you to evaluate the development of the disease in real time, even before the appearance of obvious clinical signs of relapse. A decrease in the number of circulating tumor cells after surgery and/or chemotherapy is likely to be a sign of remission. In contrast, an increase in the number of circulating tumor cells indicates a reactivation of the disease, which should lead to a re-examination of therapy. Conclusions. Early detection and characterization of circulating tumor cells is a new strategy for predicting and identifying the recurrence of cancer pathology. Circulating tumor cells detected before and after adjuvant therapy, radiotherapy, or surgical resection of the primary tumor have been described as independent risk factors for tumor recurrence and death.

Laser transfer for circulating tumor cell isolation in liquid biopsy.

75Cancer research has found in the recent years a formidable ally in liquid biopsy, a noninvasive technique that allows the study of circulating tumor cells (CTCs) and biomolecules involved in the dynamics of cancer spread like cell-free nucleid acids or tumor-derived extracellular vesicles. However, single-cell isolation of CTCs with high viability for further genetic, phenotypic, and morphological characterization remains a challenge. We present a new approach for single CTC isolation in enriched blood samples using a liquid laser transfer (LLT) process, adapted from standard laser direct write techniques. In order to completely preserve the cells from direct laser irradiation, we used an ultraviolet laser to produce a blister-actuated laser-induced forward transfer process (BA-LIFT). Using a plasma-treated polyimide layer for blister generation, we completely shield the sample from the incident laser beam. The optical transparency of the polyimide allows direct cell targeting using a simplified optical setup, in which the laser irradiation module, standard imaging, and fluorescence imaging share a common optical path. Peripheral blood mononuclear cells (PBMCs) were identified by fluorescent markers, while target cancer cells remained unstained. As a proof of concept, we were able to isolate single MDA-MB-231 cancer cells using this negative selection process. Unstained target cells were isolated and culture while their DNA was sent for single-cell sequencing (SCS). Our approach appears to be an effective approach to isolate single CTCs, preserving cell characteristics in terms of cell viability and potential for further SCS.

An ultra-compact acoustofluidic device based on the narrow-path travelling surface acoustic wave (np-TSAW) for label-free isolation of living circulating tumor cells

Obtaining highly purified intact living cells from complex environments has been a challenge, such as the isolation of circulating tumor cells (CTCs) from blood. In this work, we demonstrated an acoustic-based ultra-compact device for cell sorting, with a chip size of less than 2 × 1.5 cm2. This single actuator device allows non-invasive and label-free isolation of living cells, offering greater flexibility and applicability. The device performance was optimized with different-sized polystyrene (PS) particles and blood cells spiked with cancer cells. Using the narrow-path travelling surface acoustic wave (np-TSAW), precise isolation of 10 μm particles from a complex mixture of particles (5, 10, 20 μm) and separation of 8 μm and 10 μm particles was achieved. The purified collection of 10 μm particles with high separation efficiency (98.75%) and high purity (98.1%) was achieved by optimizing the input voltage. Further, we investigated the isolation and purification of CTCs (MCF-7, human breast cancer cells) from blood cells with isolation efficiency exceeding 98% and purity reaching 93%. Viabilities of the CTCs harvested from target-outlet were all higher than 97% after culturing for 24, 48, and 72 h, showing good proliferation ability. This novel ultra-miniaturized microfluidic chip demonstrates the ability to sorting cells with high-purity and label-free, providing an attractive miniaturized system alternative to traditional sorting methods.

Versatile Dynamic Bioactive Lubricant-Infused Surface for Effective Isolation of Circulating Tumor Cells.

The rarity of circulating tumor cells (CTCs) and the complexity of blood components present major challenges for the efficient isolation of CTCs in blood. The coexisting matters could interfere with the detection of CTCs by adhering to the binding sites on the material surface, leading to the reduced accuracy of biomarker capture in blood. Herein, we developed dynamic bioactive lubricant-infused slippery surfaces by grafting the 1H,1H,2H,2H-heptadecafluorodecyl acrylate polymer and 3-acrylamidophenylboronic acid polymer brushes on quartz plates by UV light-initiated and then grafted cancer cell-binding peptides via reversible catechol-boronate chemistry between phenylboronic acid groups and 3,4-dihydroxy-l-phenylalanine groups of peptides for high-efficient capture of CTCs and nondestructive release of the desired cells in sugar response. Patterned dynamic bioactive lubricant-infused surfaces (PDBLISs) further exhibited the improved capture efficiency of CTCs and more effective antifouling properties for nonspecific cells and blood components. Moreover, the PDBLIS can efficiently capture rare cancer cells from the mimic of cancer patient's blood samples. We anticipate that the strategy we proposed would be used in further clinical diagnosis of complicated biofluids related to a variety of tumors and exhibit good prospects and potential in future liquid biopsies.

Detection and Isolation of Circulating Tumor Cells from Breast Cancer Patients Using CUB Domain-Containing Protein 1.

In cancer metastasis, single circulating tumor cells (CTCs) in the blood and disseminated tumor cells (DTCs) in the bone marrow mediate cancer metastasis. Because suitable biomarker proteins are lacking, CTCs and DTCs with mesenchymal attributes are difficult to isolate from the bulk of normal blood cells. To establish a procedure allowing the isolation of such cells, we analyzed the cell line BC-M1 established from DTCs in the bone marrow of a breast cancer patient by stable isotope labeling by amino acids in cell culture (SILAC) and mass spectrometry. We found high levels of the transmembrane protein CUB domain-containing protein 1 (CDCP1) in breast cancer cell lines with mesenchymal attributes. Peripheral blood mononuclear cells were virtually negative for CDCP1. Confirmation in vivo by CellSearch revealed CDCP1-positive CTCs in 8 of 30 analyzed breast cancer patients. Only EpCam-positive CTCs were enriched by CellSearch. Using the extracellular domain of CDCP1, we established a magnetic-activated cell sorting (MACS) approach enabling also the enrichment of EpCam-negative CTCs. Thus, our approach is particularly suited for the isolation of mesenchymal CTCs with downregulated epithelial cancer that occur, for example, in triple-negative breast cancer patients who are prone to therapy failure.

The Prognostic Significance of Circulating Tumor Cells in Patients with Pancreatobiliary Cancer.

Circulating tumor cells (CTCs) are cancer cells which separate from the primary tumor and enter systemic circulation. In this study, it was aimed to examine the relationship between CTCs isolated and identified from the peripheral blood of patients with pancreatobiliary cancer, with the clinicopathological characteristics of the patients and their overall survival. A total of 21 patients were included the study. Density gradient centrifugation with the OncoQuick® assay was performed for isolation of CTCs from peripheral blood. In order to identify CTCs, enriched samples underwent flow cytometric analysis. The rate of patients with positive surgical margin in the high CTC group (CTC <15) was identified to be statistically significantly high compared to the group with low CTC (CTC ≤15) (83.3% vs. 16.7%; P = .041). Median neutrophil/lymphocyte ratio (NLR) was found to be higher in the high CTC group compared to the low CTC group, which was close to statistical significance (2.37 vs. 1.41; P = .055). Circulating tumor cells were identified to have a significant relationship with surgical margin positivity in our study for the first time, suggesting that the CTCs count in peripheral blood in preoperative patients may be a biomarker predicting positive surgical margin. Due to the very low number of studies assessing the relationship between CTCs and NLR, our study which identified relationship close to statistical significance between CTCs and NLR, significantly contributes to the literature on the topic of the possible role of lymphocytes in CTC clearance.

Genomic characteristics and clinical significance of CD56+ circulating tumor cells in small cell lung cancer

Circulating tumor cells (CTC) have been studied in various solid tumors but clinical utility of CTC in small cell lung cancer (SCLC) remains unclear. The aim of the CTC-CPC study was to develop an EpCAM-independent CTC isolation method allowing isolation of a broader range of living CTC from SCLC and decipher their genomic and biological characteristics. CTC-CPC is a monocentric prospective non-interventional study including treatment-naïve newly diagnosed SCLC. CD56+ CTC were isolated from whole blood samples, at diagnosis and relapse after first-line treatment and submitted to whole-exome-sequencing (WES). Phenotypic study confirms tumor lineage and tumorigenic properties of isolated cells for the 4 patients analyzed with WES. WES of CD56+ CTC and matched tumor biopsy reveal genomic alteration frequently impaired in SCLC. At diagnosis CD56+ CTC were characterized by a high mutation load, a distinct mutational profile and a unique genomic signature, compared to match tumors biopsies. In addition to classical pathways altered in SCLC, we found new biological processes specifically affected in CD56+ CTC at diagnosis. High numeration of CD56+ CTC (> 7/ml) at diagnosis was associated with ES-SCLC. Comparing CD56+ CTC isolated at diagnosis and relapse, we identify differentially altered oncogenic pathways (e.g. DLL3 or MAPK pathway). We report a versatile method of CD56+ CTC detection in SCLC. Numeration of CD56+ CTC at diagnosis is correlated with disease extension. Isolated CD56+ CTC are tumorigenic and show a distinct mutational profile. We report a minimal gene set as a unique signature of CD56+ CTC and identify new affected biological pathways enriched in EpCAM-independent isolated CTC in SCLC.

Abstract P5-02-25: Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition

Abstract Background: De novo resistance defined as progression within six months and acquired resistance are one of the major problems in the subset of metastatic (M), hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) patients without visceral crisis receiving CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy (TX). Here, we aim to identify predictive and monitoring markers of CDK4/6i resistance by conducting transcriptional profiling of circulating tumor cells (CTCs) that represent a real-time snapshot of the heterogeneity. Methods: Blood of (A) 60 HR+/HER2- MBC patients drawn at baseline of Palbociclib plus endocrine TX (TX as first line n=31, second or more lines n=29), (B) 19 HR+/HER2- MBC patients drawn before the initiation of endocrine monoTX (control) and matched blood samples of these patients after six months under TX (n=72) and at the time of progression (n=42) were analyzed. To enlarge the global CDK4/6i cohort at baseline, blood of (C) 32 patients before the initiation of Ribociclib plus endocrine TX was also drawn. Patients with progression within six months were defined as non-responders. Isolation of CTCs was conducted using positive immunomagnetic selection (AdnaTest EMT2/StemCell Select) and preamplified cDNA was analyzed by a multimarker qPCR panel utilizing QuantiNova LNA Probe assays targeting 25 genes involved in the DNA damage -, MAPK -, STAT -, Hippo – pathway or cell cycle, chemokine sensing, multidrug resistance and cell adhesion. qPCR data was normalized to CD45 and data of 20 healthy female donor controls to identify BC CTC specific overexpression signals with a specificity of &amp;gt;90% for all targets. Consumables: QIAGEN, Germany. Statistical analysis included log-rank testing and univariate Cox regression. Results: For first line CDK4/6i treated patients at baseline, CETN2 and E2F1 signals correlated significantly with worse progression-free survival (PFS) while CETN2 signals also related significantly to non-response. Furthermore, CETN2 and PCNA signals were significantly associated with worse overall survival (OS). Analyzing the Palbociclib cohort after six months of TX, PCNA signals correlated significantly with a decreased PFS while EpCAM signals showed a significant association with OS. In addition, CETN2, CXCR4, EpCAM, MLH3, WWTR1 signals after six months were shown to correlate significantly with a decreased OS and PFS and MAPK1 signals were only found in the non-responders. While non-response was related to appearing (from baseline to six months under TX) ABCC2, JUN and MAPK1 signals, disappearing ABCC2 signals were only found in the responders. Dynamics of ABCC2, CXCR4, EpCAM, JUN, MAPK1, MLH3, STAT1 and WWTR1 signals from baseline to six months under TX correlated significantly with OS and CXCR4 signal dynamics significantly with a worse PFS. At the time of progression, the presence of E2F1, JUN, MAPK1 and STAT1 signals correlated significantly with a decreased OS and in comparison to baseline analysis, the prevalence of ABCC2, EpCAM, E2F1, CETN2 and CXCR4 signals increased. Conclusion: CTC overexpression signals at baseline of targets involved in the cell cycle (CETN2 and E2F1) might be predictive markers for de novo resistance to CDK4/6i as first line TX, while ABCC2 (multidrug resistance), EpCAM (cell adhesion), E2F1, CETN2 and CXCR4 (chemokine sensing) signals could indicate acquired resistance to Palbociclib. In case of disease progression, E2F1, JUN (cell cycle) and targets of the MAPK- and STAT- pathway could be relevant targets for therapeutic strategies beyond Palbociclib TX. Monitoring and prognostic value was shown for single and repeated measurement of signals under TX in genes involved in resistance, cell cycle progression, DNA damage response (MLH3, PCNA), chemokine sensing, cell adhesion and the MAPK-, STAT- and Hippo (WWTR1) pathway. Citation Format: Sabine Kasimir-Bauer, Charlotte Gruber, Stefanos Moukas, Mitra Tewes, Hans-Christian Kolberg, Rainer Kimmig, Corinna Keup. Transcriptional profiling of CTCs in metastatic breast cancer patients in the course of CDK4/6 inhibition [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-25.

Abstract P3-05-45: Circulating tumor cells, immunohistochemical subtypes, and genes mutation as prognostic markers in HER2 negative metastatic breast cancer patients candidates to chemotherapy

Abstract Background: In the era of targeted therapies, chemotherapy (CT) is still a valuable treatment option for patients (pts) with HER2 negative metastatic breast cancer (MBC). The identification of predictive and prognostic markers might improve treatment response and survival. Here we investigated the role of tumor subtypes, circulating tumor cells (CTCs), and mutations in genes or pathways of interest, in predicting response to CT and prognosis of HER2 negative MBC pts within AARES trial. Methods: AARES is an open label multicentric randomised phase 2 trial comparing a DNA-damaging (arm A: cisplatin 25 mg/m2/day, day 1-3 + cyclophosphamide 600 mg/m2 day 1) versus (vs) a non-DNA-damaging (arm B: capecitabine 1000 mg/m2 bid/day, day 1-14 + vinorelbine 60 mg/m2/day, day 1,8) CT regimen in pts with HER2 negative MBC. Archival tumor tissue samples and blood samples were collected at baseline. The Cell SearchTM system was used for CTCs isolation and enumeration and a cut-off of 5 CTC/7,5 ml was used. Tumor subtypes were based on locally assessed hormone receptors and HER2 status. The luminal-like subtype (Lum) was defined by ER or PR positivity, while the triple negative subtype (TN) by ER, PR, and HER2 negativity. Tissue samples were used for DNA extraction and next generation sequencing analysis using a target enrichment panel of 170 genes (TruSight 170, Illumina). Primary endpoint was objective response rate (ORR) assessed for the two treatment arms. Progression free survival (PFS) and overall survival (OS) were evaluated as secondary endpoints, and estimated with the Kaplan-Meier method. ORR, PFS and OS were correlated with CTC counts, tumor subtypes, and mutational status of genes/pathway of interest (PIK3CA, TP53, BRCA1, BRCA2, PI3K/AKT pathway (PI3K/AKT)). Results: AARES enrolled 102 pts from 2011 to 2016 across 9 Italian centers. Of these, 77 pts were evaluable for ORR. Median follow up was 32 months. Overall, median age was 57. The majority of pts had Lum tumors (73%), while 27% had TN. 86% of pts had visceral metastases, and 52% had 3 or more metastatic sites. 48% of pts received the study treatment as 1st line, 32% as 2nd line, and 19% as 3rd line. Out of the 77 pts with ORR data, 41 (53%) were CTC- and 36 (47%) CTC+. A larger proportion of pts with Lum tumors were CTC+ (54% n=30), while TN tumors were mainly CTC- (71% n=15). 49 pts had adequate tumor tissue for sequencing analysis. TP53 mutations (mut) were found in 33% of pts, BRCA1/2 mut in 14%, PIK3CA mut in 35%, and PI3K/AKT mut in 47%. ORR was 24% and 37% in arm A vs arm B, respectively (p= 0.2), and no difference in ORR was observed by tumor subtypes (Lum vs TN), and CTCs count (+ vs -). PFS and OS were assessable on the whole population (n=102) and did not significantly differ by treatment arms. Median OS (mOS) was higher in Lum pts compared to TN (24 months (mo) vs 15.4 mo, p=0.048) while median PFS (mPFS) did not differ according to tumor subtypes (p=0.28). Overall, CTCs count was not significantly associated with mPFS or OS however in pts with TN tumors and CTC-, mPFS and mOS were significantly longer (mPFS: 4.44 mo vs 2.56 mo in CTC- and CTC+ subgroups, respectively, p=0.00087 and mOS: 22.07 mo vs 3.57 mo in CTC- and CTC+ subgroups, respectively, p&amp;lt; 0.0001). On the other hand, no differences were observed in Lum pts categorized according to CTC status (p=0.83 for mPFS, p=0.54 for mOS). Finally, pts with PI3K/AKT mut had a significantly worse PFS compared to wild type in the overall population (p=0.0091) as well as in Lum (p=0.034) and TN pts (p=0.0052). Conclusions: CTCs and tumor subtypes were not predictive of response to CT regimens in HER2 negative MBC pts. A number of CTC &amp;gt;5 in TN MBC, and mutations in the PI3K/AKT pathway, identified a subgroup of pts with worse prognosis, potentially candidates for alternative treatments. Further studies are needed to confirm these results in a larger population. Citation Format: Emanuela Risi, Marta Pestrin, Chiara Biagioni, Dario Romagnoli, Ilenia Migliaccio, Francesca Galardi, Francesca De Luca, Matteo Benelli, Erica Moretti, Giuseppina Sanna, Luca Livraghi, Silvia Cappadona, Roberta Di Marsico, Domenico Amoroso, Angelo Martignetti, Angela S. Ribecco, Elena Rota Caremoli, Luigi Coltelli, Fabio Puglisi, Luca Malorni, Laura Biganzoli. Circulating tumor cells, immunohistochemical subtypes, and genes mutation as prognostic markers in HER2 negative metastatic breast cancer patients candidates to chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-45.

Abstract P5-06-04: The prognostic value of c-MET monitoring by using c-MET-enriched circulating tumor cells in HR-positive HER2-negative metastatic breast cancer

Abstract [Background] As the development of endocrine resistance and late recurrences are the major clinical concerns in hormone receptor (HR)-positive/HER2-negative metastatic breast cancer (MBC) patients, biomarkers to predict the occurrence of endocrine resistance or disease progression are crucial for improving patient outcomes. Aberrant HGF/c-MET signaling pathway has been reported to play a role in various cellular processes in cancer. Estrogen Receptor 1 (ESR1) mutations, encoding estrogen receptor α, are associated with endocrine resistance in HR+ breast cancer. PIK3CA hotspot mutations that induce hyperactivation of the PI3K are found in 30-40% of HR+ advanced breast cancers. In this context, we evaluated the prognostic values of c-MET-enriched CTC, ESR1 mutations, PIK3CA mutations, and cfDNA concentrations detected in the blood of HR+HER2- MBC patients. [Methods] MBC patients were prospectively enrolled during standard treatments at Samsung Medical Center (IRB No.2019-08-119). Circulating tumor cells (CTCs) were isolated using the GenoCTC® with c-MET-enriched or EpCAM-enriched CTC isolation kits (Genobio Corp., South Korea) from 4mL of blood each. PIK3CA and ESR1 hotspot mutations were analyzed by droplet digital PCR kits (Gencurix Inc., South Korea). cfDNA concentrations were calculated using ESR1 gene copy numbers from plasma. To compare the proportion of c-MET overexpression between primary breast tumors and metastatic sites in HR+HER2- breast cancer patients, primary breast (n=358) and metastatic sites (n=27) were independently collected. c-MET expression was evaluated by an immunohistochemistry assay using an anti-total c-MET (SP44) antibody with a Ventana Discovery XY automated system according to the manufacturer’s instruction. c-MET overexpression was defined if the staining was scored as 2+ or 3+. Progression-free survival (PFS) was defined as the time from blood draw to the first of either disease progression or death during standard therapy. [Results] Out of 93 patients with HR+ MBC, analysis was performed in 63 HR+HER2- MBC patients. Seventeen patients (27%) had one or more EpCAM-enriched CTCs, and fourteen patients (22%) had one or more c-MET-enriched CTCs detected in their blood. The median follow-up time and median time to censoring were 8.4 months and 18.7 months, respectively. According to the Kaplan-Meier survival analysis by log-rank test, c-MET-enriched CTCs, cfDNA concentrations, and ESR1 mutations were significantly associated with PFS (p=0.0026, 0.0064, and 0.011, respectively). However, PIK3CA mutations and EpCAM-enriched CTCs were not statistically significant with PFS (p=0.38 and 0.86, respectively). Multivariate analysis showed that both c-MET-enriched CTCs (HR=3.5, p=0.014) and cfDNA concentrations (HR=2.2, p=0.031) were independent predictors for PFS in HR+HER2- MBC. The proportion of c-MET overexpression was significantly higher in metastatic sites (22.2%) than in primary breast tumors (4.7%) in HR+HER2- breast cancer patients (p=0.00002). As c-MET-enriched CTCs and cfDNA concentrations were independent predictors of disease progression, patients were divided into two groups depending on the result of c-MET-enriched CTCs and cfDNA concentration. When patients with low c-MET-enriched CTC and cfDNA concentrations were classified as a low-risk group and other patients into a high-risk group, the high-risk group had a shorter PFS than the low-risk group (p=0.003). [Conclusion] This study provided c-MET-enriched CTCs and cfDNA concentrations calculated by ESR1 copy numbers in patient blood were significant independent predictors of disease progression in HR+HER2- MBC. The poor prognosis in the c-MET-enriched CTC-high group and the difference in the c-MET overexpression rate between the primary breast and metastatic sites suggested the importance of monitoring c-MET-enriched CTCs in the blood of HR+HER2- MBC patients. Citation Format: Jieun Park, Eun Sol Chang, Ji-Yeon Kim, Chaithanya Chelakkot, Minjung Sung, Ji-Young Song, Kyungsoo Jung, Na Young Kim, Hyegyeong Lee, Mi-Ran Kang, Yeon Hee Park, Young Kee Shin, Yoon-La Choi. The prognostic value of c-MET monitoring by using c-MET-enriched circulating tumor cells in HR-positive HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-06-04.

Interpretatively automated identification of circulating tumor cells from human peripheral blood with high performance.

The detection and analysis of circulating tumor cells (CTCs) would be of aid in a precise cancer diagnosis and an efficient prognosis assessment. However, traditional methods that rely heavily on the isolation of CTCs based on their physical or biological features suffer from intensive labor, thus being unsuitable for rapid detection. Furthermore, currently available intelligent methods are short of interpretability, which creates a lot of uncertainty during diagnosis. Therefore, we propose here an automated method that takes advantage of bright-field microscopic images with high resolution, so as to take an insight into cell patterns. Specifically, the precise identification of CTCs was achieved by using an optimized single-shot multi-box detector (SSD)-based neural network with integrated attention mechanism and feature fusion modules. Compared to the conventional SSD system, our method exhibited a superior detection performance with the recall rate of 92.2%, and the maximum average precision (AP) value of 97.9%. To note, the optimal SSD-based neural network was combined with advanced visualization technology, i.e., the gradient-weighted class activation mapping (Grad-CAM) for model interpretation, and the t-distributed stochastic neighbor embedding (T-SNE) for data visualization. Our work demonstrates for the first time the outstanding performance of SSD-based neural network for CTCs identification in human peripheral blood environment, showing great potential for the early detection and continuous monitoring of cancer progression.

Poly(ethylene oxide) Concentration Gradient-Based Microfluidic Isolation of Circulating Tumor Cells

Circulating tumor cells (CTCs) have emerged as promising circulating biomarkers for non-invasive cancer diagnosis and management. Isolation and detection of CTCs in clinical samples are challenging due to the extreme rarity and high heterogeneity of CTCs. Here, we describe a poly(ethylene oxide) (PEO) concentration gradient-based microfluidic method for rapid, label-free, highly efficient isolation of CTCs directly from whole blood samples. Stable concentration gradients of PEO were formed within the microchannel by co-injecting the side fluid (blood sample spiked with 0.025% PEO) and center fluid (0.075% PEO solution). The competition between the elastic lift force and the inertial lift force enabled size-based separation of large CTCs and small blood cells based on their distinct migration patterns. The microfluidic device could process 1 mL of blood sample in 30 min, with a separation efficiency of >90% and an enrichment ratio of >700 for tumor cells. The isolated CTCs from blood samples were enumerated by immunofluorescence staining, allowing for discrimination of breast cancer patients from healthy donors with an accuracy of 84.2%. The concentration gradient-based microfluidic separation provides a powerful tool for label-free isolation of CTCs for a wide range of clinical applications.

Circulating tumour cell isolation, analysis and clinical application.

Circulating tumour cells (CTCs) are cancer cells that circulate in the bloodstream after being shed from solid tumours. They can lead to tumour recurrence and metastasis. CTCs play a significant role as biomarkers for early diagnosis, therapy response monitoring, and prognostication. However, CTCs are rare and heterogeneous, with usually only a single-digit number in one millilitre of blood. Additionally, a circadian rhythm is involved in the release of CTCs into the peripheral circulation. Due to these biological properties, higher demands are placed on the isolation of CTCs, and current capture methods struggle to enrich all CTCs present in blood. As yet, these limitations have hampered the clinical application of CTCs. In this review, we focus on the biological properties and clinical applications of CTCs and current CTC enrichment and isolation methods. Combined enrichment methods based on physical and biological properties are considered instrumental for the development of highly specific and sensitive CTC capture methods. The utilization of CTCs in conjunction with other liquid biopsy components (such as ctDNA) may yield more clinically useful information and the circadian rhythmicity of CTC release may change the way to evaluate and treat patients.

Isolation, Detection and Analysis of Circulating Tumour Cells: A Nanotechnological Bioscope.

Cancer is one of the dreaded diseases to which a sizeable proportion of the population succumbs every year. Despite the tremendous growth of the health sector, spanning diagnostics to treatment, early diagnosis is still in its infancy. In this regard, circulating tumour cells (CTCs) have of late grabbed the attention of researchers in the detection of metastasis and there has been a huge surge in the surrounding research activities. Acting as a biomarker, CTCs prove beneficial in a variety of aspects. Nanomaterial-based strategies have been devised to have a tremendous impact on the early and rapid examination of tumor cells. This review provides a panoramic overview of the different nanotechnological methodologies employed along with the pharmaceutical purview of cancer. Initiating from fundamentals, the recent nanotechnological developments toward the detection, isolation, and analysis of CTCs are comprehensively delineated. The review also includes state-of-the-art implementations of nanotechnological advances in the enumeration of CTCs, along with future challenges and recommendations thereof.

CTC-5: A novel digital pathology approach to characterise circulating tumour cell biodiversity

Metastatic progression and tumor evolution complicates the clinical management of cancer patients. Circulating tumor cell (CTC) characterization is a growing discipline that aims to elucidate tumor metastasis and evolution processes. CTCs offer the clinical potential to monitor cancer patients for therapy response, disease relapse, and screen ‘at risk' groups for the onset of malignancy. However, such clinical utility is currently limited to breast, prostate, and colorectal cancer patients. Further understanding of the basic CTC biology of other malignancies is required to progress them towards clinical utility. Unfortunately, such basic clinical research is often limited by restrictive characterization methods and high-cost barrier to entry for CTC isolation and imaging infrastructure. As experimental clinical results on applications of CTC are accumulating, it is becoming clear that a two-tier system of CTC isolation and characterization is required. The first tier is to facilitate basic research into CTC characterization. This basic research then informs a second tier specialised in clinical prognostic and diagnostic testing.This study presented in this manuscript describes the development and application of a low-cost, CTC isolation and characterization pipeline; CTC-5. This approach uses an established ‘isolation by size’ approach (ScreenCell Cyto) and combines histochemical morphology stains and multiparametric immunofluorescence on the same isolated CTCs. This enables capture and characterization of CTCs independent of biomarker-based pre-selection and accommodates both single CTCs and clusters of CTCs. Additionally, the developed open-source software is provided to facilitate the synchronization of microscopy data from multiple sources (https://github.com/CTC5/). This enables high parameter histochemical and immunofluorescent analysis of CTCs with existing microscopy infrastructure without investment in CTC specific imaging hardware.Our approach confirmed by the number of successful tests represents a potential major advance towards highly accessible low-cost technology aiming at the basic research tier of CTC isolation and characterization. The biomarker independent approach facilitates closing the gap between malignancies with poorly, and well-defined CTC phenotypes. As is currently the case for some of the most commonly occurring breast, prostate and colorectal cancers, such advances will ultimately benefit the patient, as early detection of relapse or onset of malignancy strongly correlates with their prognosis.