Circulating Tumor Cells Biomarker Research Articles

Impact of circulating tumor DNA genomic mutations and circulating tumor cells biomarker duo on clinical concordance in localized, progressive, and metastatic disease.

e14546 Background: Genomic mutations have been identified from circulating tumor DNA (ctDNA) that correlates positively with clinical disease status. EGFR and intracellular cell progression/proliferation pathway-BRCA1/2 and TP53 genes drive high ctDNA load in progressive cancer patients. Circulating tumor cells (CTC) indicate Cellular Residual Disease (CRD). ctDNA and CTC as dual biomarkers offer prediction of tumor progression and metastasis implicative for early detection and treatment modifications. Methods: Retrospectively in 96 cancer patients (lung, colon-rectal, breast, stomach, etc.) who recently underwent treatment were investigated for presence of CTCs and genomic mutations from ctDNA using OncoMonitor Test. Libraries were prepared using a hybridization-capture method covering 1000 targets with mean sequencing depth 5000X on Illumina Nextseq 2000. Test detected genomic alterations from single nucleotide variation (SNVs), small insertions and deletions (INDELs), copy number variations (CNVs), and translocations (fusions) using a 96 gene panel. CTCs were isolated using the OncoDiscover platform, with CK18+, PD-L1+, CD45- in1.5 ml of blood. Results: In 96 pan-cancer patients, 15.6% patients (n=15) were identified with localized progressive disease with no metastasis from radiological findings, of which 60% (n=9) patients showed at least 1 genomic finding from ctDNA.12.5% (n=12) patients were identified as metastatic from their radiological findings of which 58.3% (n=7) showed presence of at least 1 CTC. 33.3% (n=4) patients showed 2 CTCs and 5 patients had no CTCs. In addition, these metastatic patients showed the presence of ctDNA load in 66.6% (n=8) patients with at least 1 genomic finding. In metastatic disease cohort, CTC enumeration showed concordance of 58.3% (n=7) with metastatic radiological findings and genomic findings from ctDNA showed concordance in 66.6% (n=8) patients with metastatic radiological findings. 23.9% (n=23) patients from the cohort were radiological identified with stable/treatment responsive disease of which 73.9% (n=17) patients were not detected with genomic mutations from ctDNA and 26.0% (n=6) patients were CTC -ve, concordant with radiological findings. 26.0% (n=6) patients had at least 1 genomic finding contributing to discordance with the radiological findings. Genomic findings from duo offered concordance with radiological findings in 26.6% (n=4) patients with progressive disease, 41.6% (n=5) in metastatic disease, and 17.3% (n=4) in patients with stable/treatment responsive disease. Conclusions: Patients with progressive and metastatic disease from radiological findings showed concordance with the dual ctDNA and CTC biomarkers. Concordance of ctDNA in progressive disease and CTC in metastatic disease is indicative of individual significance.

Comprehensive Analysis of CXCR4, JUNB, and PD-L1 Expression in Circulating Tumor Cells (CTCs) from Prostate Cancer Patients.

CXCR4, JUNB and PD-L1 are implicated in cancer progression and metastasis. The current study investigated these biomarkers in CTCs isolated from metastatic prostate cancer (mPCa) patients at the RNA and protein levels. CTCs were isolated from 48 mPCa patients using the Ficoll density gradient and ISET system (17 out of 48). The (CK/PD-L1/CD45) and (CK/CXCR4/JUNB) phenotypes were identified using two triple immunofluorescence stainings followed by VyCAP platform analysis. Molecular analysis was conducted with an EpCAM-dependent method for 25/48 patients. CK-8, CK-18, CK-19, JUNB, CXCR4, PD-L1, and B2M (reference gene) were analyzed with RT-qPCR. The (CK+/PD-L1+/CD45-) and the (CK+/CXCR4+/JUNB+) were the most frequent phenotypes (61.1% and 62.5%, respectively). Furthermore, the (CK+/CXCR4+/JUNB-) phenotype was correlated with poorer progression-free survival [(PFS), HR: 2.5, p = 0.049], while the (CK+/PD-L1+/CD45-) phenotype was linked to decreased overall survival [(OS), HR: 262.7, p = 0.007]. Molecular analysis revealed that 76.0% of the samples were positive for CK-8,18, and 19, while 28.0% were positive for JUNB, 44.0% for CXCR4, and 48.0% for PD-L1. Conclusively, CXCR4, JUNB, and PD-L1 were highly expressed in CTCs from mPCa patients. The CXCR4 protein expression was associated with poorer PFS, while PD-L1 was correlated with decreased OS, providing new biomarkers with potential clinical relevance.

Abstract PO5-15-06: NVIGEN X® Comprehensive Liquid Biopsy for Sensitive ctDNA, Circulating Tumor Cells (CTC), and Protein Detection in Breast Cancer: Next-Generation Sequencing, Patient Case Studies, and Clinical Implications

Abstract Background Breast cancer (BC) represents the most prevalent cancer and is a leading cause of cancer related mortality among women worldwide. Despite notable therapeutic advancements, concern for metastatic recurrence remains a significant challenge. Liquid biopsy has emerged as a promising method for monitoring cancer treatment efficacy and disease progression. However, existing technologies predominantly focus on ctDNA, and their clinical utility is hindered by limited detection sensitivity and accuracy. To address these challenges, NVIGEN has developed NVIGEN X® comprehensive liquid biopsy, a novel minimally invasive approach that integrates ctDNA, CTC, and protein biomarkers. This comprehensive method could enable longitudinal monitoring of tumor dynamics, offering valuable insights into cancer biology, treatment responses, and emerging therapeutic targets. Here, we showcase compelling patient case studies, and the potential clinical implications of our technology for an exciting and evolving field in cancer diagnostics. Method Patients with advanced breast cancer were prospectively identified and consented. 10mL blood per timepoint was collected in Streck tubes. ctDNA, CTC and proteins were captured from a single tube of blood using NVIGEN magnetic nanoparticles according to established protocols. Following DNA extraction, ctDNA and CTC samples underwent NVIGEN’s highly sensitive sample workflow, optimized for NGS data accuracy and efficiency, employing hybridization capture with a 180 gene customizable cancer panel. Sequenced data were processed with NVIGEN’s proprietary high-sensitivity data analysis pipeline. Gene alterations identified from both ctDNA and CTC samples were analyzed and integrated to provide a comprehensive view of the tumor profile. Protein biomarkers of interest were detected using NVIGEN’s on-beads ELISA assay. Correlation analysis was performed to examine the relationship between the detected gene alterations, protein biomarkers, ctDNA/CTC data, and clinicopathologic features. Treatment response and identification of potential new treatment targets were evaluated based on the integrated analysis of ctDNA, CTC, protein biomarkers, and patient information. Result We collected 94 blood samples from 85 patients. Here we will present data from initial 36 patient samples. Of these 36 patients, 18 were tested with ctDNA/protein biomarkers (duo assays), and 18 were tested with ctDNA/CTC/protein biomarkers (trio assays). Comparison between duo and trio samples revealed that trio samples provided 2.5 times the number of detected variants compared to duo samples, with the median of variant numbers in duo assays being 52 (range 22-442), and in trio assays being 130 (range 73-703). Over 50% of the detected variants fell within the 0.1-0.5% variant allele frequency (VAF) range (number 2599) with total variant number being 5123. Several patient case studies were conducted using serial blood samples. These case studies revealed notable patterns of important gene alterations, such as ESR1, ERBB2 and PIK3CA, and demonstrated trends in the presence of these genes in ctDNA, CTC, or their coexistence. Protein biomarker information was correlated with ctDNA, CTC NGS data, and patient clinical status. Conclusions The analysis of the presented data from 36 patient samples with advanced breast cancer highlight the clinical relevance and potential significance of utilizing ctDNA, CTC and protein biomarkers in monitoring disease dynamics, treatment response, and guiding personalized treatment approaches. Our results suggest that individual protein biomarker analysis may be crucial in supporting personalized diagnostics and enabling more effective personalized medicine strategies. Citation Format: Aihua Fu, Minh Ton, Kevan Wang, Weiwei Gu, Henry Jin, Nuzhat Shaikh, Sasha Madan, Shreya Perepa, Tianhong Li, Minetta Liu, Heather Parsons, George Sledge, Fauzia Riaz. NVIGEN X® Comprehensive Liquid Biopsy for Sensitive ctDNA, Circulating Tumor Cells (CTC), and Protein Detection in Breast Cancer: Next-Generation Sequencing, Patient Case Studies, and Clinical Implications [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-15-06.

Abstract PO1-16-02: Correlation of Circulating Tumor Cells (CTC) with Clinical Characteristics, Pathological Factors, and Treatment Response in Patients with Metastatic Breast Cancer (MBC)

Abstract Background: Circulating Tumor Cells (CTC) can be isolated in 40-80% of patients with metastatic breast cancer (MBC). High levels of CTC, defined as ≥5/7.5 ml of blood are associated with shorter progression-free survival and overall survival. CTC can be tested for clinically relevant biomarkers, such as ER, and HER2 status, and have the potential to guide therapy as well as help with disease monitoring. We investigated CTC detection rate, its correlation with clinical characteristics, pathological characteristics, and response to treatment in patients with any type of metastatic breast cancer who progressed on at least one line of therapy. Methods: Eligible patients with MBC were enrolled in the IMAGE-II study (Individualized Molecular Analyses Guide Efforts in Breast Cancer) NCT02965755, in which we obtained archival tissue as part of the standard of care, and prospectively collected serial blood samples for CTC analysis. We compared CTC levels and biomarker status with clinical factors, tissue-based pathology, and molecular biomarkers. We assessed whether changes in CTC count correlated with treatment response. Blood samples were collected at baseline (Day 1), after 1-2 weeks of therapy, after 8-12 weeks, and at subsequent restaging (every 8-12 weeks). Medical records were reviewed every 3 months for ongoing treatment response, and death. Samples were processed at the Biocept CLIA-certified Laboratory. CTC were enumerated by the presence of CD45- and DAPI+ cells. Further CTC characterization was performed by antibody staining of specific protein biomarkers (ER, HER2). Fisher’s exact test was used to evaluate the association between baseline CTC < 5 and ≥5/7.5ml with patient characteristics. McNemar’s test was used to assess discordance between tissue-based and CTC-defined markers. Results: Between 1/26/2018 and 12/31/22 baseline samples were collected from 70 women with a median age of 56 (36-82) who were enrolled at four study sites. CTC was detected in 59 (84%) of participants. Baseline CTC counts were < 5/7.5 ml in 37/59 (63%) and ≥5/7.5 ml in 22/59 (37%) of participants. Differences between breast cancer subtype and CTC-receptor status were observed (Table 1). Among the 41 patients who were ER-positive, 31 (76%) were CTC ER-negative(p< 0.001). Among 29 patients who were ER-negative, 4 (14%) were CTC ER-Positive (P< 0.001). Among the 7 patients who were HER2 positive, 2(29%) were HER2 positive on CTC. Among 63 patients who were HER2 negative, 7(11%) had HER2 expression on their CTC. The discordance in the classification of HER2 wasn't statistically significant (p=0.77). Elevated CTC at baseline was more frequently detected in younger participants (< 50 years old) (55% vs 27%; P=0.22), in Black women compared to White (60 % vs 29 %, P=0.27), and in participants with visceral vs non-visceral metastasis (52% vs 28 %, P=0.40). Patients with CTC ≥5 vs < 5/7.5mL at baseline had a shorter duration of anti-HER2-based therapy (61.5 vs 836 days, p=0.04). There were no statistically significant differences among participants who received chemotherapy agents (316.5 vs 365.5 days, P=0.88), endocrine therapy (376 vs 490 days, P=0.89), or overall therapy (272 vs 390 days, P=0.21). Conclusions: We observed significant differences in the expression of ER between tumor tissue and CTC, which can be partly due to tumor evolution over time. Additionally, participants who are young, Black, and those who have visceral metastasis may have higher CTC counts. Higher CTC counts were associated with a shorter duration of anti-HER2 therapy. Although it didn’t meet statistical significance, a similar trend was observed in patients who received chemotherapy and endocrine therapy. Table 1: MBC Tissue-Based Subtype and CTC-receptor status at baseline Citation Format: Asnakech Bayable, Tingchang Wang, Amanda Blackford, Jessica Tao, Jenna Canzoniero, Seoho Lee, Faith Too, Barbara Blouw, Mary Wilkinson, Rima Couzi, Antonio Wolff, Christie Hiton, Ben Park, Vered Stearns, Cesar Santa-Maria. Correlation of Circulating Tumor Cells (CTC) with Clinical Characteristics, Pathological Factors, and Treatment Response in Patients with Metastatic Breast Cancer (MBC) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-16-02.

Abstract 7493: Real-time monitoring of CTC number, biomarker expression, and kinetics as prognostic and predictive markers in patients with GI malignancies

Abstract Background: Most of the utility in the clinic regarding liquid biopsies has been around circulating tumor DNA (ctDNA). ctDNA analysis provides valuable insight into mutational burden and therapeutic targets, but the speed and cost of analysis are prohibitive especially when it comes to serial testing. Using a cohort of patients with advanced or metastatic gastrointestinal (GI) cancers, we herein show the feasibility of using circulating tumor cell (CTC) enumeration, biomarker analysis, and kinetics as complementary to or as an alternative to ctDNA testing. Methods: Using the RareCyte platform, nucleated cells from blood were collected, spread on slides, stained, and imaged with CyteFinder® for CTC identification (CK/EpCAM+, CD45-) and quantification of biomarkers (PD-L1/HER2 or Ki67/EGFR). CTC enumeration (CLIA-accredited CTC test) and biomarker status for each patient were tracked over time and compared with ctDNA mutational analysis and tumor burden. Results: CTCs were detected in 60/70 samples (86%) and in 36/38 unique patients (95%). On average, more CTCs were detected in baseline samples from colorectal cancer patients compared to other subtypes (Table 1). Moreover, multiple patients showed pronounced changes in CTC number that correlated with treatment response, as well as strong correlation between CTC and tissue biomarker expression e.g. HER2. Rapid decline and/or CTC clearance was seen as early as a few days into starting effective systemic therapy. The average turnaround time for CTC testing was 5-7 days. Table 1. CTC values in initial baseline blood draw sample Gastrointestinal cancer subtype # of patients Average # of CTCs per 7.5mL blood Median # of CTCs per 7.5mL blood Minimum # of CTCs per 7.5mL blood Maximum # of CTCs per 7.5mL blood Colorectal carcinoma 27 84 3 0 1378 Cholangiocarcinoma 3 8 3 1 23 Pancreatic cancer 3 2 2 0 3 Hepatocellular carcinoma 2 4 5 0 10 Gallbladder cancer 1 6 6 3 8 Appendix cancer 1 2 2 1 3 Anal cancer 1 0 0 0 0 Conclusions: Our study emphasizes that real-time monitoring of CTCs is complementary to traditional tumor burden monitoring via imaging and ctDNA analysis. CTCs offer multiple unique advantages vs ctDNA including early response assessment within days of initiating therapy, a substantial decrease in cost of serial testing, and the ability to assess clinically relevant cell surface protein biomarkers e.g. HER2 and PD-L1. Citation Format: Erin G. Bayer, Brock M. Bartels, Rachel N. Ponting, Areeb Lutfi, Maaz K. Afghan, Arturo B. Ramirez, Pashtoon M. Kasi. Real-time monitoring of CTC number, biomarker expression, and kinetics as prognostic and predictive markers in patients with GI malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7493.

Diagnostic Performance of Epithelial Cell Adhesion Molecule for Early Detection of Hepatocellular Carcinoma Among HCV High-Risk Patients.

Hepatocellular carcinoma (HCC) is often diagnosed at advanced stage where hopeless for effective therapies. Identification of more reliable biomarkers for early detection of HCC is urgently needed. Circulating tumor cells (CTCs) represent a unique liquid biopsy carrying comprehensive biological information of the primary tumor. Herein, we sought to develop a novel score based on the combination of the most significant CTCs biomarkers with routine laboratory tests for accurate detection of HCC. Epithelial cell adhesion molecule (EpCAM), α-fetoprotein, albumin, and platelets count were assayed in HCC patients (98), liver cirrhosis patients (77). Areas under receiving operating curve (AUCs) were calculated and used for construction on novel score. A novel score named EpCAM-HCC = AFP (U/L) × 0.11 - Albumin (g/dl) × 1.5 + EpCAM % × 2.9 - Platelets count (×109)/L× 0.75 - 93. EpCAM-HCC score produce AUC of 1 for differentiate patients with HCC from those with liver cirrhosis with sensitivity and specificity of a cut-off 1.7 (i.e., less than 1.7 the case is considered cirrhotic, whereas above 1.7 it is considered HCC. EpCAM-HCC score could replace AFP during screening of HCV patients and early detection of HCC.

Development of a multiplex assay to assess activated p300/CBP in circulating prostate tumor cells.

Reduced SIRT2 deacetylation and increased p300 acetylation activity leads to a concerted mechanism of hyperacetylation at specific histone lysine sites (H3K9, H3K14, and H3K18) in castration-resistant prostate cancer (CRPC). We examined whether circulating tumor cells (CTCs) identify patients with altered p300/CBP acetylation. CTCs were isolated from 13 advanced PC patients using Exclusion-based Sample Preparation (ESP) technology. Bound cells underwent immunofluorescent staining for histone modifying enzymes (HMEs) of interest and image capture with NIS-Elements software. Using the cBioPortal PCF/SU2C dataset, the response of CRPC to androgen receptor signaling inhibitors (ARSI) was analyzed in 50 subjects. Staining optimization and specificity revealed clear expression of acetyl-p300, acetyl-H3K18, and SIRT2 on CTCs (CK positive, CD45 negative cells). Exposure to A-485, a selective p300/CBP catalytic inhibitor, reduced p300 and H3K18 acetylation. In CRPC patients, a-p300 strongly correlated with its target acetylated H3k18 (Pearson's R = 0.61), and SIRT2 expression showed robust negative correlation with a-H3k18 (R = -0.60). A subgroup of CRPC patients (6/11; 55%) demonstrated consistent upregulation of acetylation based on these markers. To examine the clinical impact of upregulation of the CBP/p300 axis, CRPC patients with reduced deacetylase SIRT2 expression demonstrate shorter response times to ARSI therapy (5.9 vs. 12 mo; p = 0.03). A subset of CRPC patients demonstrate increased p300/CBP activity based on a novel CTC biomarker assay. With further development, this biomarker suite may be used to identify candidates for CBP/p300 acetylation inhibitors in clinical development.

Baits-trap chip for accurate and ultrasensitive capture of living circulating tumor cells.

Accurate analysis of living circulating tumor cells (CTCs) plays a crucial role in cancer diagnosis and prognosis evaluation. However, it is still challenging to develop a facile method for accurate, sensitive, and broad-spectrum isolation of living CTCs. Herein, inspired by the filopodia-extending behavior and clustered surface-biomarker of living CTCs, we present a unique baits-trap chip to achieve accurate and ultrasensitive capture of living CTCs from peripheral blood. The baits-trap chip is designed with the integration of nanocage (NCage) structure and branched aptamers. The NCage structure could "trap" the extended filopodia of living CTCs and resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture (∼95% accuracy) of living CTCs independent of complex instruments. Using an in-situ rolling circle amplification (RCA) method, branched aptamers were easily modified onto the NCage structure, and served as "baits" to enhance the multi-interactions between CTC biomarker and chips, leading to ultrasensitive (99%) and reversible cell capture performance. The baits-trap chip successfully detects living CTCs in broad-spectrum cancer patients and achieves high diagnostic sensitivity (100%) and specificity (86%) of early prostate cancer. Therefore, our baits-trap chip provides a facile, accurate, and ultrasensitive strategy for living CTC isolation in clinical. STATEMENT OF SIGNIFICANCE: A unique baits-trap chip integrated with precise nanocage structure and branched aptamers was developed for the accurate and ultrasensitive capture of living CTCs. Compared with the current CTC isolation methods that are unable to distinguish CTC viability, the nanocage structure could not only "trap" the extended-filopodia of living CTCs, but also resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture of living CTCs. Additionally, benefiting from the "baits-trap" synergistic effects generated by aptamer modification and nanocage structure, our chip achieved ultrasensitive, reversible capture of living CTCs. Moreover, this work provided a facile strategy for living CTC isolation from the blood of patients with early-stage and advanced cancer, exhibiting high consistency with the pathological diagnosis.

Circulating Tumor Cells in Breast Cancer: A Step Toward Precision Medicine for Real-Time Monitoring of Metastasis

Tumor metastasis involves the dissemination of malignant cells into the basement membrane and vascular system contributes to the circulating pool of these markers. In this context our aim has been focused on development of a non-invasive score based on degradation of glycosaminoglycans in the extracellular matrix for assessment of metastasis in patients with breast cancer. Circulating tumor cells (CTCs) represent a unique liquid biopsy carrying comprehensive biological information of the primary tumor. Herein, we sought to develop a novel score based on the combination of the most significant CTCs biomarkers with and routine laboratory tests for accurate detection of Metastases in patients with breast cancer. Cytokeratin 18 (CK18), Cytokeratin 19 (CK19) and CA15.3 were assayed in metastatic breast cancer patients (88), non-metastatic breast cancer patients (129) and healthy control (32). Areas under receiving operating curve (AUCs) were calculated and used for construction on novel score. A novel score named CTC-MBS = CA15.3 (U/L) × 0.08 + CK 18 % × 2.9 + CK19 × 3.1. CTC-MBS score produces AUC of 1 for differentiate patients with metastatic breast cancer from those with non-metastatic breast cancer with sensitivity and specificity of a cut-off 0 (i.e., less than 0 the case is considered metastatic, whereas above 0 it is considered non-metastatic. CTC-MBS score is a novel, non-invasive and simple can applied to discriminate patients with metastatic breast cancer and could replace CA15.3 during screening and follow-up of breast cancer patients.

Profiling of Circulating Tumor Cells for Screening of Selective Inhibitors of Tumor-Initiating Stem-Like Cells.

A critical barrier to effective cancer therapy is the improvement of drug selectivity, toxicity, and reduced recurrence of tumors expanded from tumor-initiating stem-like cells (TICs). The aim is to identify circulating tumor cell (CTC)-biomarkers and to identify an effective combination of TIC-specific, repurposed federal drug administration (FDA)-approved drugs. Three different types of high-throughput screens targeting the TIC population are employed: these include a CD133 (+) cell viability screen, a NANOG expression screen, and a drug combination screen. When combined in a refined secondary screening approach that targets Nanog expression with the same FDA-approved drug library, histone deacetylase (HDAC) inhibitor(s) combined with all-trans retinoic acid (ATRA) demonstrate the highest efficacy for inhibition of TIC growth in vitro and in vivo. Addition of immune checkpoint inhibitor further decreases recurrence and extends PDX mouse survival. RNA-seq analysis of TICs reveals that combined drug treatment reduces many Toll-like receptors (TLR) and stemness genes through repression of the lncRNA MIR22HG. This downregulation induces PTEN and TET2, leading to loss of the self-renewal property of TICs. Thus, CTC biomarker analysis would predict the prognosis and therapy response to this drug combination. In general, biomarker-guided stratification of HCC patients and TIC-targeted therapy should eradicate TICs to extend HCC patient survival.

Virtual-freezing fluorescence imaging flow cytometry with 5-aminolevulinic acid stimulation and antibody labeling for detecting all forms of circulating tumor cells.

Circulating tumor cells (CTCs) are precursors to cancer metastasis. In blood circulation, they take various forms such as single CTCs, CTC clusters, and CTC-leukocyte clusters, all of which have unique characteristics in terms of physiological function and have been a subject of extensive research in the last several years. Unfortunately, conventional methods are limited in accurately analysing the highly heterogeneous nature of CTCs. Here we present an effective strategy for simultaneously analysing all forms of CTCs in blood by virtual-freezing fluorescence imaging (VIFFI) flow cytometry with 5-aminolevulinic acid (5-ALA) stimulation and antibody labeling. VIFFI is an optomechanical imaging method that virtually freezes the motion of fast-flowing cells on an image sensor to enable high-throughput yet sensitive imaging of every single event. 5-ALA stimulates cancer cells to induce the accumulation of protoporphyrin (PpIX), a red fluorescent substance, making it possible to detect all cancer cells even if they show no expression of the epithelial cell adhesion molecule, a typical CTC biomarker. Although PpIX signals are generally weak, VIFFI flow cytometry can detect them by virtue of its high sensitivity. As a proof-of-principle demonstration of the strategy, we applied cancer cells spiked in blood to the strategy to demonstrate image-based detection and accurate classification of single cancer cells, clusters of cancer cells, and clusters of a cancer cell(s) and a leukocyte(s). To show the clinical utility of our method, we used it to evaluate blood samples of four breast cancer patients and four healthy donors and identified EpCAM-positive PpIX-positive cells in one of the patient samples. Our work paves the way toward the determination of cancer prognosis, the guidance and monitoring of treatment, and the design of antitumor strategies for cancer patients.

A clinical-grade liquid biomarker detects neuroendocrine differentiation in prostate cancer.

BackgroundNeuroendocrine prostate cancer (NEPC) is an aggressive subtype, the presence of which changes the prognosis and management of metastatic prostate cancer.MethodsWe performed analytical validation of a Circulating Tumor Cell (CTC) multiplex RNA qPCR assay to identify the limit of quantification (LOQ) in cell lines, synthetic cDNA, and patient samples. We next profiled 116 longitudinal samples from a prospectively collected institutional cohort of 17 patients with metastatic prostate cancer (7 NEPC, 10 adenocarcinoma) as well as 265 samples from 139 patients enrolled in 3 adenocarcinoma phase II trials of androgen receptor signaling inhibitors (ARSIs). We assessed a NEPC liquid biomarker via the presence of neuroendocrine markers and the absence of androgen receptor (AR) target genes.ResultsUsing the analytical validation LOQ, liquid biomarker NEPC detection in the longitudinal cohort had a per-sample sensitivity of 51.35% and a specificity of 91.14%. However, when we incorporated the serial information from multiple liquid biopsies per patient, a unique aspect of this study, the per-patient predictions were 100% accurate, with a receiver-operating-curve (ROC) AUC of 1. In the adenocarcinoma ARSI trials, the presence of neuroendocrine markers, even while AR target gene expression was retained, was a strong negative prognostic factor.ConclusionOur analytically validated CTC biomarker can detect NEPC with high diagnostic accuracy when leveraging serial samples that are only feasible using liquid biopsies. Patients with expression of NE genes while retaining AR-target gene expression may indicate the transition to neuroendocrine differentiation, with clinical characteristics consistent with this phenotype.FundingNIH (DP2 OD030734, 1UH2CA260389, R01CA247479, and P30 CA014520), Department of Defense (PC190039 and PC200334), and Prostate Cancer Foundation (Movember Foundation - PCF Challenge Award).

Single-Cell Identification of Melanoma Biomarkers in Circulating Tumor Cells.

Simple SummaryIdentification and investigation of cancer biomarkers is a pivotal area of modern cancer research. One such biomarker that has garnered considerable attention in the field is a class of free-floating tumor cells found in the blood known as circulating tumor cells (CTCs). Existing methods for CTC isolation tend to isolate cells based on a single marker enrichment that fails to capture the full heterogeneity that is commonplace in tumor cell populations. By incorporating a broader antibody cocktail, we designed a new approach to isolate CTCs for single-cell RNA analysis. Using common melanoma markers, a consistent and cost-effective approach was developed that we demonstrate to be successful with both patient and cultured cells. This methodology provides a framework to capture a more heterogeneous population of CTCs with wide applications in both research and clinical fields.The current standard for investigating tumors is surgical biopsy, which is costly, invasive, and difficult to perform serially. As an adjunct, circulating tumor cells (CTCs)—cells that have broken away from the primary tumor or metastatic sites—can be obtained from a blood draw and offer the potential for obtaining serial genetic information and serving as biomarkers. Here, we detail the potential for melanoma CTCs to serve as biomarkers and discuss a clinically viable methodology for single-cell CTC isolation and analysis that overcomes previous limitations. We explore the use of melanoma CTC biomarkers by isolating and performing single-cell RNA sequencing on CTCs from melanoma patients. We then compared transcriptional profiles of single melanoma CTCs against A375 cells and peripheral blood mononuclear cells to identify unique genes differentially regulated in circulating melanoma tumor cells. The information that can be obtained via analysis of these CTCs has significant potential in disease tracking.

Diagnostic Performance of Circulating Tumor Cells for Predicting of Hepatocellular Carcinoma in Hepatitis C Virus-High Risk Patients: Role of Liquid Biopsy.

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver and a global health problem. It is often diagnosed at advanced stage where hopeless for effective therapies. Identification of more reliable biomarkers for early detection of HCC is urgently needed. circulating tumor cells (CTCs) represent a unique liquid biopsy carrying comprehensive biological information of the primary tumor. Herein, we sought to develop a novel score based on the combination of the most significant CTCs biomarkers with and routine laboratory tests for accurate detection of HCC. Cytokeratin 18 (CK18), Cytokeratin 19 (CK19), albumin, platelets count, and α-fetoprotein were assayed in HCC patients (42), liver cirrhosis patients (83) and healthy control (20). Areas under receiving operating curve (AUCs) were calculated and used for construction on novel score. A novel score named HCC-CTCs = AFP (U/L) × 0.08 - Albumin (g/dl) × 84 + CK 18 % × 2.9 + CK19 × 3.1- Platelets count (×109)/L× 0.75- 510. HCC-CTCs score produce AUC of 1 for differentiate patients with HCC from those with liver cirrhosis with sensitivity and specificity of a cut-off 0. HCC-CTCs score could replace AFP during screening of HCV patients and early detection of HCC.

Abstract 1952: Validation of enhanced performance of the AccuCyte®-CyteFinder® platform for circulating tumor cell characterization

Abstract Analysis of circulating tumor cells (CTCs) by multiparameter immunofluorescence (IF) microscopy allows non-invasive characterization of cancer cell biomarker expression in real time. This information can be helpful in prognosis, treatment selection, and stratification of cancer patients. AccuCyte® is a density-based unbiased isolation method that transfers nucleated cells from whole blood to slides for the characterization of CTCs and other rare cells. RarePlex® panel kits are IF staining reagents used on automated slide staining instruments to label cells to differentiate CTCs from white blood cells (WBC). CyteFinder® is a seven-channel automated fluorescent imaging system that rapidly scans microscope slides and applies machine learning algorithms to identify CTCs. Together, these technologies provide an end-to-end solution for CTC characterization. For analysis, blood is drawn into AccuCyte blood collection tubes (BCTs) containing a preservative which maintains cell properties prior to processing onto slides. Once slides are prepared, they can be stored at -20°C without significant biomarker degradation. This flexible workflow allows investigators to bank samples for batch analysis and to begin sample collection prior to validating the IF assay to be used. This study was designed to evaluate: (1) stability time between collection in the AccuCyte BCT and sample processing; (2) performance of an improved version of the AccuCyte kit with higher nucleated cell isolation capacity; and (3) storage time that AccuCyte prepared slides can be banked frozen prior to staining. The study was performed using model CTCs and cancer patient samples. Metrics to determine performance were CTC recovery and mean fluorescence intensity (MFI) of biomarker expression. Our results demonstrate that the AccuCyte BCT preserves blood components for at least 5 days after collection without significant effect on CTC recovery or biomarker expression. The latest version of the AccuCyte kit demonstrated a higher cell isolation capacity and could collect up to 60% more nucleated blood cells than the previous version, increasing CTC recovery. The increased capacity was demonstrated in patients treated with hematopoietic growth factors, whose WBC count was significantly higher than the normal range. Finally, accelerated-aging study results demonstrated that AccuCyte-prepared slides can be stored at -20°C for at least 4 years without significant effect on most biomarkers tested. In conclusion, enhancements to the AccuCyte-CyteFinder platform reported here increase flexibility and performance for analysis of CTCs in global clinical trials by allowing longer periods of time before collected blood samples need to be processed and by extending the length of time processed slides can be banked before they are stained. Citation Format: Arturo B. Ramirez, Lillian Costandy, Brady S. Gardner, Ryan H. Huston, A Anders Larson Tevis, Casey E. Helmicki, Alisa C. Clein, Daniel E. Sabath, Joshua J. Nordberg, Tad C. George. Validation of enhanced performance of the AccuCyte®-CyteFinder® platform for circulating tumor cell characterization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1952.

P-194 Circulating tumor cell enumeration, biomarker analyses, and kinetics in patients with colorectal cancer and other GI malignancies

“Liquid biopsies” are revolutionizing cancer care. The broad term often refers to identification of circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) in individuals with cancer. Most of the work pertaining to liquid biopsies has been about ctDNA. Data pertaining to work on CTCs as the other kind of liquid biopsies is scarce. Here we embarked on an effort to not only show feasibility of doing CTC enumeration and biomarker analyses, but also serial kinetics of CTCs in response to therapy in patients with colorectal cancer and other GI malignancies. This was a prospective study with collection and analyses of circulating tumor cells (CTCs) done in real-time in patients with colorectal cancer and other GI malignancies. We chose to identify CTCs using two different methodologies/platforms: RareCyte platform which relies on sepration based on the density of CTCs, and Parsortix platform which relies on the size/compressibility of CTCs. The study was reviewed by the institutional review board (IRB), and all patients (n = 59) signed a written informed consent before collecting blood samples at the University of Iowa Holden Comprehensive Cancer Center. Blood samples (4 tubes: 2 tubes for Parsortix system and 2 tubes for Rarecycte system) were collected from each patient at each time point. Each tube was subjected to CTC analysis and results averaged (Total = 150 draws; 281 test results) from all the patients. In addition to identification and enumeration of CTCs using standard definitions of nuclear/epithelial markers, additional biomarkers studied included PD-L1, HER2, EGFR, Ki-67, and where adequate confirmation with panel based single cell sequencing was also performed. Cell cultures were attempted for the parsortix collections. Patients with colorectal cancer (CRC) had the highest number of CTCs (Mean: 15.8; Median: 7.5). This was in sharp contrast to the number of CTCs in patients with pancreatic cancer (PC) (Mean: 4.2; Median: 3). At least a third of patients with CRC had at least 3 CTCs. Another 17.4% and 11.4% had at least 10, and at least 20 CTCs in CRC; while no patients with PC had more than 20 CTCs. In addition, we detected a significantly lower number of CTCs from patients receiving treatment versus patients not receiving treatment (Median 2.7 versus 0.7). Striking differences were also observed in CTCs for those with untreated/progressive disease versus those who had responding/stable disease (Median of 2.7 versus 0). Biomarker analyses on 4 markers HER2/PD-L1/Ki-67/EGFR were feasible when CTCs were detected. There was overall agreement on CTCs detected on either platform. Not suprisingly, the agreement was higher when more CTCs were detectable. Where available, single cell sequencing data was concordant with clonal aberrations on ctDNA/tissue NGS sequencing. This is one of the largest prospective endeavors in GI cancers showing feasiblity and value of capturing and analyzing CTCs in a prospective fashion using two very different platforms. Timing is key to CTC based protocols and analyses. Varied downstream capabilities of different platforms and the fact that they are capturing an overlapping but different bucket of CTCs lends pros and cons to each approach.

A preliminary study on the association between epithelial-mesenchymal transition and circulating tumor cells in renal cell carcinoma.

BackgroundCirculating tumor cells (CTCs) are considered useful prognostic factors for various cancers, and in 2014, our research group conducted a comparative experiment of CTC detection in patients with renal cell cancer (RCC). However, the reason for the low detection rate of CTCs in cancer patients using the CellSearch® system is still unknown, although it has been hypothesized to be attributed to the likelihood that CTCs undergoing epithelial-mesenchymal transition (EMT) do not express the CTC biomarkers cytokeratin (CK)8/18/19 or epithelial cell adhesion molecule (EpCAM). The overall aim of the current study was to investigate the expression levels of CK8/18/19 and EpCAM in relation to the EMT biomarkers vimentin and E-cadherin in patients with RCC.MethodsPatients with RCC who had undergone radical nephrectomy or partial resection between May 2014 and December 2014 were initially recruited.ResultsAmong 34 RCC patients, nine co-expressed EpCAM and CK8/18/19 in primary tumor tissues. The CellSearch® results showed that CK8/18/19 was expressed in 5 of 6 patients (5/6) and EpCAM was expressed in 6 patients (6/6). However, the isolation by size of tumor cells (ISET) technique showed these were co-expressed in only four of the 10. The expression of CK8/18/19, EpCAM, vimentin, and E-cadherin was distributed unequally in different enumeration groups of CTCs (all P>0.05), and the positive expression of CK8/18/19 was correlated with neutrophil number and tumor size (P<0.05). The positive expression of vimentin was correlated with the Karnofsky Performance Status (KPS) score and clinical stage of renal cancer patients (P<0.05).ConclusionsOur results indirectly proved the occurrence of EMT in the formation of CTCs by comparing and analyzing the expression of CK8/18/19 and EpCAM in renal cancer tissues and the detection results of CTCs.

Is Circulating DNA and Tumor Cells in Myeloma the Way Forward?

Multiple myeloma (MM) is the second deadliest hematological cancer. Despite the enormous innovation on MM treatment in the last decades, still 48% of patients die within 5 years after diagnosis. MM diagnosis and therapeutic strategy mainly rely on direct bone marrow (BM) assessment. Given the MM heterogeneity, BM biopsies do not accurately reflect the whole disease status, hampering accurate disease prognosis. Moreover, biopsies are painful and invasive procedures, highlighting the need for non-invasive and more accurate source of biomarkers. Liquid biopsies are promising sources of biomarkers that may overcome these limitations. Peripheral blood carries circulating myeloma components that are being extensively explored since the last few years as an alternative to BM aspirates. These include circulating tumor cells (CTC), cell-free DNA (cfDNA), and extracellular vesicles containing miRNA and proteins. The current review summarizes scientific evidence establishing BM as a gold standard for the diagnosis, prognosis, and evaluation of minimal residual disease. We discuss the last advances regarding cfDNA and CTC biomarkers from peripheral blood in patients with MM as well as the statistical validations. This paper addresses the technological hurdles associated with liquid biopsies and examines the missing steps for their inclusion into the clinical practice.

Ultrasensitive Nanopore Sensing of Mucin 1 and Circulating Tumor Cells in Whole Blood of Breast Cancer Patients by Analyte-Triggered Triplex-DNA Release.

The characterization of circulating tumor cells (CTCs) by liquid biopsy has a great potential for precision medicine in oncology. Here, a universal and tandem logic-based strategy is developed by combining multiple nanomaterials and nanopore sensing for the determination of mucin 1 protein (MUC1) and breast cancer CTCs in real samples. The strategy consists of analyte-triggered signal conversion, cascaded amplification via nanomaterials including copper sulfide nanoparticles (CuS NPs), silver nanoparticles (Ag NPs), and biomaterials including DNA hydrogel and DNAzyme, and single-molecule-level detection by nanopore sensing. The amplification of the non-DNA nanomaterial gives this method considerable stability, significantly lowers the limit of detection (LOD), and enhances the anti-interference performance for complicated samples. As a result, the ultrasensitive detection of MUC1 could be achieved in the range of 0.0005-0.5 pg/mL, with an LOD of 0.1 fg/mL. Moreover, we further tested MUC1 as a biomarker for the clinical diagnosis of breast cancer CTCs under double-blind conditions on the basis of this strategy, and MCF-7 cells could be accurately detected in the range from 5 to 2000 cells/mL, with an LOD of 2 cells/mL within 6 h. The detection results of the 19 clinical samples were highly consistent with those of the clinical pathological sections, nuclear magnetic resonance imaging, and color ultrasound. These results demonstrate the validity and reliability of our method and further proved the feasibility of MUC1 as a clinical diagnostic biomarker for CTCs.

Prognostic Significance of Gene Expression and DNA Methylation Markers in Circulating Tumor Cells and Paired Plasma Derived Exosomes in Metastatic Castration Resistant Prostate Cancer

Simple Summary“Liquid biopsy”, based on the analysis of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), provides non-invasive real-time monitoring of tumor evolution and therapeutic efficacy. We performed for the first time a direct comparison study on gene expression and DNA methylation markers in CTCs and paired plasma-derived exosomes and evaluated their prognostic significance in metastatic castration resistant prostate cancer. Our results revealed for the first time a significantly higher positivity of all markers in EpCAM-positive CTCs compared to plasma-derived exosomes. We report that in EpCAM-positive CTCs, CK-19, PSMA, TWIST1 expression and GSTP1 methylation are significantly correlated with worse overall survival (OS), while in exosomes, CK-8 expression and GSTP1 and RASSF1A methylation status were significantly correlated with a lower OS. We also enumerated CTC and tumor-derived extracellular vesicles (tdEVs) using CellSearch (CS) and found a correlation between the CTC and tumor-derived extracellular vesicles (tdEVs) enumeration values.Liquid biopsy, based on the analysis of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), provides non-invasive real-time monitoring of tumor evolution and therapeutic efficacy. We performed for the first time a direct comparison study on gene expression and DNA methylation markers in CTCs and paired plasma-derived exosomes and evaluated their prognostic significance in metastatic castration resistant prostate cancer. This prospective liquid biopsy (LB) study was based on a group of 62 metastatic castration resistant prostate cancer (mCRPC) patients and 10 healthy donors (HD) as controls. Identical blood draws were used to: (a) enumerate CTC and tumor-derived extracellular vesicles (tdEVs) using CellSearch (CS) and (b) analyze CTCs and paired plasma-derived exosomes at the gene expression and DNA methylation level. CTCs were enumerated using CellSearch in 57/62 patients, with values ranging from 5 to 854 cells/7.5 mL PB. Our results revealed for the first time a significantly higher positivity of gene expression markers (CK-8, CK-18, TWIST1, PSMA, AR-FL, AR-V7, AR-567 and PD-L1 mRNA) in EpCAM-positive CTCs compared to plasma-derived exosomes. GSTP1, RASSF1A and SCHLAFEN were methylated both in CTC and exosomes. In CTCs, Kaplan–Meier analysis revealed that CK-19 (p = 0.009), PSMA (p = 0.001), TWIST1 (p = 0.001) expression and GSTP1 (p = 0.001) methylation were correlated with OS, while in exosomes GSTP1 (p = 0.007) and RASSF1A (p = 0.001) methylation was correlated with OS. Our direct comparison study of CTCs and exosomes at gene expression and DNA methylation level, revealed for the first time a significantly higher positivity in EpCAM-positive CTCs compared to plasma-derived exosomes. Future perspective of this study should be the evaluation of clinical utility of molecular biomarkers in CTCs and exosomes on independent multicentric cohorts with mCRPC patients.