Is circulating tumor cell count-driven cost-effective for first-line therapy choice in HR+/HER2- metastatic breast cancer in the United States?

BACKGROUND

Circulating tumor cell (CTC) counting may be a useful non-invasive biomarker that helps patients choose first-line treatment options. Nevertheless, the cost of CTC inspection may impose an economic burden on patients, necessitating the simultaneous consideration of both its clinical effectiveness and cost. We evaluated the cost-effectiveness of CTC count-guided chemotherapy and endocrine therapy as first-line therapy for HR+/HER2-metastatic breast cancer (MBC) from the perspective of US payers.

METHODS

Based on the STIC CTC trial, a Markov model was constructed for three health states, and health outcomes were measured in quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were performed to assess the robustness of the incremental cost per QALY.

RESULTS

The base-case analysis revealed that CTC count-driven treatment was associated with improved effectiveness by 0.07 QALYs and increased the overall cost by $9187.05 compared with clinician-driven first-line treatment choices, leading to an ICER of $138 354.15 per QALY. One-way sensitivity analysis indicated that the model was most sensitive to the cost of treatment for neutropenia and the utility for PFS; probability sensitivity analysis indicated that CTC count-driven treatment choices would be considered the cost-effective option at a willingness-to-pay threshold of $150 000 per QALY.

CONCLUSIONS

The findings of this cost-effectiveness analysis suggest that, at the current price of CTC enumeration, choosing first-line treatment options based on CTC count is a cost-effectiveness approach for treating patients with HR+/HER2- MBC in the US.

The correlation study between TOP2A gene expression in circulating tumor cells and chemotherapeutic drug resistance of patients with breast cancer

BACKGROUND

Patients with breast cancer (BC) at advanced stages have poor outcomes because of high rate of recurrence and metastasis. Biomarkers for predicting prognosis remain to be explored. This study aimed to evaluate the relationships between circulating tumor cells (CTCs) and outcomes of BC patients.

PATIENTS AND METHODS

A total of 50 female were enrolled in this study. Their diagnoses were determined by clinical characteristics, image data, and clinical pathology. CTC subtypes and TOP2A gene expression on CTCs were detected by CanPatrol™ technology and triple color in situ RNA hybridization (RNA-ISH), which divided into epithelial CTCs (eCTCs), mesenchymal CTCs (MCTCs), and hybrid CTCs (HCTCs) based on their surface markers. Hormone receptor, including estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) expression, was measured by immunohistochemistry (IHC) method before treatment. The risk factors for predicting recurrence and metastasis were calculated by COX risk regression model. The progression-free survival (PFS) of patients was determined using Kaplan-Meier survival curve.

RESULTS

The patients with a large tumor size (≥ 3 cm) and advanced tumor node metastasis (TNM) stages had high total CTCs (TCTCs) (P < 0.05). These patients also had high TOP2A expression level. COX risk regression analysis indicated that TOP2A expression levels in TCTCs, ER + , HER-2 + , and TNM stages were critical risk factors for recurrence and metastasis of patients (P < 0.05). The PFS of patients with ≥ 5 TCTCs, ≥ 3 HCTCs, and positive TOP2A expression in ≥ 3 TCTCs was significantly longer than that in patient with < 5 TCTCs, < 3 HCTCs, and TOP2A expression in < 3 TCTCs (P < 0.05). In contrast, the PFS of patients with positive hormone receptors (ER + , PR + , HER-2 +) also was dramatically lived longer than that in patients with negative hormone receptor expression.

CONCLUSIONS

High TCTC, HCTCs, and positive TOP2A gene expression on CTCs were critical biomarkers for predicting outcomes of BC patients. Positive hormone receptor expression in BC patients has significant favor PFS.

Prognostic value of circulating tumor cells associated with white blood cells in solid cancer: a systematic review and meta-analysis of 1471 patients with solid tumors

BACKGROUND

The clinical relevance of circulating tumor cell-white blood cell (CTC-WBC) clusters in cancer prognosis is a subject of ongoing debate. This study aims to unravel their contentious predictive value for patient outcomes.

METHODS

We conducted a comprehensive literature search of PubMed, Embase, and Cochrane Library up to December 2022. Eligible studies that reported survival outcomes and examined the presence of CTC-WBC clusters in solid tumor patients were included. Hazard ratios (HR) were pooled to assess the association between CTC-WBC clusters and overall survival (OS), as well as progression-free survival (PFS)/disease-free survival (DFS)/metastasis-free survival (MFS)/recurrence-free survival (RFS). Subgroup analyses were performed based on sampling time, treatment method, detection method, detection system, and cancer type.

RESULTS

A total of 1471 patients from 10 studies were included in this meta-analysis. The presence of CTC-WBCs was assessed as a prognostic factor for overall survival and PFS/DFS/MFS/RFS. The pooled analysis demonstrated that the presence of CTC-WBC clusters was significantly associated with worse OS (HR = 2.44, 95% CI: 1.74-3.40, P < 0.001) and PFS/DFS/MFS/RFS (HR = 1.83, 95% CI: 1.49-2.24, P < 0.001). Subgroup analyses based on sampling time, treatment method, detection method, detection system, cancer type, and study type consistently supported these findings. Further analyses indicated that CTC-WBC clusters were associated with larger tumor size (OR = 2.65, 95% CI: 1.58-4.44, P < 0.001) and higher alpha-fetoprotein levels (OR = 2.52, 95% CI: 1.50-4.22, P < 0.001) in hepatocellular carcinoma. However, no significant association was found between CTC-WBC clusters and TNM stage, depth of tumor invasion, or lymph node metastasis in the overall analysis.

CONCLUSIONS

CTC-WBC clusters are negative predictors for OS and PFS/DFS/MFS/RFS in patients with solid tumors. Monitoring CTC-WBC levels may provide valuable information for predicting disease progression and guiding treatment decisions.

Liquid-based biomarkers in breast cancer: looking beyond the blood

In recent decades, using circulating tumor cell (CTC), circulating tumor DNA (ctDNA), circulating tumor RNA (ctRNA), exosomes and etc. as liquid biomarkers has received enormous attention in various tumors, including breast cancer (BC). To date, efforts in the area of liquid biopsy predominantly focus on the analysis of blood-based markers. It is worth noting that the identifications of markers from non-blood sources provide unique advantages beyond the blood and these alternative sources may be of great significance in offering supplementary information in certain settings. Here, we outline the latest advances in the analysis of non-blood biomarkers, predominantly including urine, saliva, cerebrospinal fluid, pleural fluid, stool and etc. The unique advantages of such testings, their current limitations and the appropriate use of non-blood assays and blood assays in different settings are further discussed. Finally, we propose to highlight the challenges of these alternative assays from basic to clinical implementation and explore the areas where more investigations are warranted to elucidate its potential utility.

Association of survivin positive circulating tumor cell levels with immune escape and prognosis of osteosarcoma

PURPOSE

Function of survivin protein (encoded by BIRC5) in circulating tumor cells (CTCs) of osteosarcoma (OS) has not been investigated. The goal of this study is to determine whether the expression of survivin protein of CTCs is associated with circulating immune cell infiltration and disease prognosis of OS.

METHODS

Blood samples of 20 patients with OS were collected. CanPatrol™ CTC enrichment technology combined with in situ hybridization (ISH) was applied to enrich and test CTCs and survivin protein. Bioinformation analysis combined with data of routine blood test was used to verify the association between survivin and immune cell infiltration in circulatory system. To screen independent prognostic factors, Kaplan-Meier survival curve, univariate and multivariable Cox regression analyses were performed.

RESULTS

Bioinformatics analysis showed that BIRC5 was strongly negatively related to lymphocyte, including T cell, NK cell and B cell, which released that BIRC5 played a key role in immune escape via reducing immune cell infiltration in circulatory system. Meanwhile, the number of survivin+ CTCs was significantly negatively connection with lymphocyte count (R = -0.56, p = 0.011), which was consistent with bioinformatics analysis. Kaplan-Meier curve showed that the overall survival rate in high survivin+ CTCs group was significantly lower than low group (88.9% vs 36.4%, p = 0.04). Multivariable Cox regression analyses showed that survivin+ CTCs were an independent prognostic factor (p = 0.019).

CONCLUSION

These findings suggested that survivin protein played a key role in immune escape of CTCs and the presence of survivin+ CTCs might be a promising prognostic factor in OS patients.

A Novel Filtration Membrane for Clustered Circulating Tumor Cell Extraction: A Prospective Feasibility Study

BACKGROUND/AIM

Circulating tumor cells (CTCs) have garnered attention as biomarkers for therapeutic response and prognosis in malignant neoplasms. Nonetheless, existing literature predominantly relies on surrogate markers of tumor cells or focuses on single-cell CTC, failing to adequately address the challenge of detecting cluster-forming CTCs, which bear considerable prognostic implications. This prospective study aims to validate the efficacy of a novel filtration membrane, namely Soft Micro Pore Filter (S-MPF®), for rare cell recovery in detecting CTCs through the analysis of clinical samples.

PATIENTS AND METHODS

Patients with confirmed lung cancer or highly suspected lung cancer based on specific criteria (solid tumor size >2.0 cm, serum carcinoembryonic level >7.5 ng/ml, maximum standard uptake value derived from fluorodeoxyglucose-position emission tomography >2.9) were included in the study. CTCs were extracted from preoperative peripheral arterial blood samples using S-MPF®, and the validity of the filtration system was positively verified.

RESULTS

Out of the 25 enrolled patients, 23 had lung cancer. CTC positivity was observed in 17 cases (73.9%), whereas cluster CTC positivity was observed in 16 cases (69.6%), with a median count of two clusters. Single CTC positivity was observed in 11 cases (52.1%), with a median count of one cell.

CONCLUSION

The utilization of the newly developed S-MPF® filtration membrane exhibited a high rate of CTC identification, demonstrating its suitability for clinical applications.

Prognostic value of stem-like circulating tumor cells in patients with cancer: a systematic review and meta-analysis

Despite increasing interest in the study of circulating tumor cells (CTC) subsets, especially epithelial-mesenchymal transition (EMT) and stem cells subsets of CTC that play a key role in tumor recurrence and metastasis, there is no evidence from meta-analyses that shows the correlation between stem-like CTCs and prognosis in cancer patients. Thus, we performed a meta-analysis to assess its prognostic value. Sixteen articles were screened by searching the PubMed, Embase, Cochrane, China National Knowledge Internet (CNKI) and Wanfang databases. The hazard ratio (HR) and 95% confidence interval (95% CI) extracted from each article were summarized. Patients with positive stem-like CTCs in peripheral blood had significantly shorter overall survival (OS, HR: 2.58, 95% CI 1.76-3.79, P < 0.00001), progression-free survival (PFS, HR: 2.21, 95% CI 1.26-3.89, P = 0.006) and disease-free survival (DFS, HR: 2.53, 95% CI: 1.12-5.70, P = 0.03). This study provides the first meta-analysis evidence for the prognostic value of stem-like CTCs, demonstrating that these cells are associated with poor prognosis in cancer patients.Systematic review registrationCRD42022322062.

The circulation stage of the metastatic cascade: A mathematical description and its clinical implications

Metastatic cascade is a multi-stage process that starts with separation of a cancer cell from the primary tumor and ends with the emergence of a detectable metastasis. In the process the initiator cancer cell enters the circulatory system (intravasates), flows with the blood, and exits the circulation (extravasates) into an organ or tissue. The time period between intravasation and extravasation constitutes the circulation stage of the metastatic cascade. This stage is unique in that it lends itself naturally to various non-invasive observations and measurements in an individual cancer patient. This creates an opportunity for gaining insight into metastasis, its mathematical modeling, and designing diagnostic/prognostic tools and new cancer therapies. Although mechanisms of intravasation, survival and extravasation of circulating tumor cells (CTCs) are very complex and largely unknown, mathematical modeling of the circulation stage of the metastatic cascade is facilitated by two inter-related factors: a relative simplicity of the circulatory network and the cyclic nature of blood flow. The article presents a single-subject stochastic model of CTC dynamics that leads to simple formulas, applicable to any homogeneous CTC population, for organ-specific extravasation probabilities, the distribution and expected value of the number, X, of circulation cycles completed by a CTC prior to extravasation, and the average circulation time. In particular, we found that the distribution of random variable X is geometric G(x), where parameter x is measurable, at least in principle, in an individual subject. We also discuss implications of our results for cancer research and treatment.

Can we define breast cancer HER2 status by liquid biopsy?

Human Epidermal growth factor Receptor 2 (HER2) assessment is crucial for breast cancer treatment. Therapeutic decisions for recurrent cases often rely on primary tumor status. However, mounting evidence suggests that tumors show dynamic changes and up to 10% of breast cancer modify their initial status during progression. It is still debated whether these changes reflect a biological evolution of the disease or are secondary to primary tumor heterogeneity. Certainly, repeating HER2 assessment during breast cancer trajectory is important for the increasing availability of effective anti-HER2 drugs. In response to this need, circulating biomarkers such as circulating tumor cells (CTCs) and cell-free circulating tumor DNA (ctDNA) offer the potential to safely and repeatedly assess HER2 status over time. This chapter outlines current methods for testing HER2 in CTCs and ctDNA, and reviews clinical trials evaluating its prognostic and predictive value in patients with breast cancer, as well as recent advances in the field.

Rapid detection of EGFR mutation in CTCs based on a double spiral microfluidic chip and the real-time RPA method

Circulating tumor cells (CTCs) are cells shed from primary or metastatic tumors and spread into the peripheral bloodstream. Mutation detection in CTCs can reveal vital genetic information about the tumors and can be used for "liquid biopsy" to indicate cancer treatment and targeted medication. However, current methods to measure the mutations in CTCs are based on PCR or DNA sequencing which are cumbersome and time-consuming and require sophisticated equipment. These largely limited their applications especially in areas with poor healthcare infrastructure. Here we report a simple, convenient, and rapid method for mutation detection in CTCs, including an example of a deletion at exon 19 (Del19) of the epidermal growth factor receptor (EGFR). CTCs in the peripheral blood of NSCLC patients were first sorted by a double spiral microfluidic chip with high sorting efficiency and purity. The sorted cells were then lysed by proteinase K, and the E19del mutation was detected via real-time recombinase polymerase amplification (RPA). Combining the advantages of microfluidic sorting and real-time RPA, an accurate mutation determination was realized within 2 h without professional operation or complex data interpretation. The method detected as few as 3 cells and 1% target variants under a strongly interfering background, thus, indicating its great potential in the non-invasive diagnosis of E19del mutation for NSCLC patients. The method can be further extended by redesigning the primers and probes to detect other deletion mutations, insertion mutations, and fusion genes. It is expected to be a universal molecular diagnostic tool for real-time assessment of relevant mutations and precise adjustments in the care of oncology patients.

Circulating tumor cell abundance in head and neck squamous cell carcinoma decreases with successful chemoradiation and cetuximab treatment

Head and neck squamous cell carcinoma (HNSCC) is a common and deadly cancer. Circulating tumor cell (CTC) abundance may a valuable, prognostic biomarker in low- and intermediate-risk patients. However, few technologies have demonstrated success in detecting CTCs in these populations. We prospectively collected longitudinal CTC counts from two cohorts of patients receiving treatments at our institution using a highly sensitive device that purifies CTCs using biomimetic cell rolling and dendrimer-conjugated antibodies. In patients with intermediate risk human papillomavirus (HPV)-positive HNSCC, elevated CTC counts were detected in 13 of 14 subjects at screening with a median of 17 CTC/ml (range 0.2-2986.5). A second cohort of non-metastatic, HPV- HNSCC subjects received cetuximab monotherapy followed by surgical resection. In this cohort, all subjects had elevated baseline CTC counts median of 73 CTC/ml (range 5.4-332.9) with statistically significant declines during treatment. Interestingly, two patients with recurrent disease had elevated CTC counts during and following treatment, which also correlated with growth of size and ki67 expression in the primary tumor. The results suggest that our device may be a valuable tool for evaluating the success of less intensive treatment regimens.

Perioperative change of circulating tumor cells in cytoreductive radical prostatectomy for oligometastatic hormone-sensitive prostate cancer: the preliminary safety evidence from long-term oncologic outcomes

Surgical manipulation has a risk of triggering the shedding of circulating tumor cells (CTCs) in patients with malignancies, However, perioperative change of circulating tumor cells in cytoreductive radical prostatectomy (CRP) for patients with oligometastatic hormone-sensitive prostate cancer (omHSPC) has not yet been well documented. This study aimed to assess whether CRP is a safe procedure for patients with omHSPC by monitoring the perioperative change of CTCs and investigating its impact on long-term oncologic outcomes. We have observed a significant decrease between the median CTC counts before and after surgery (6 vs. 4, p = 0.026). Comparing preoperative and postoperative CTC levels, seven patients increased (CTC increase group), one did not change and nineteen decreased (CTC non-increase group). PSA response rates in CTC increase group were lower than those in CTC non-increase group (73.0% vs 99.8%, p = 0.162), and nadir PSA was higher in CTC increase group (0.043 vs 0.003, p = 0.072). The CTC increase was positively correlated with the nadir PSA (r = 0.386, p = 0.047). The median follow-up period was 71.6 months, we found that there was no significant difference in clinical-pathological, operative variables or long-term oncologic outcomes between perioperative CTC increase and non-increase groups. In the entire cohort, the CTC level significantly decreased after surgery. There was no significant differences in long-term oncologic outcomes between the CTC increase and non-increase groups, implying that CRP potentially represents a safe procedure for the treatment of patients with omHSPC. The results need to be confirmed in a prospective large-scale clinical trial.

Feasibility study of expressing epcam + /vimentin + CTC in prostate cancer diagnosis

PURPOSE

Prostate cancer (PCa) is one of the most common malignancies in men and one of the leading causes of cancer-related deaths; circulating tumor cells (CTC) are malignant cells that have broken off from original tumor or metastatic sites and extravasated into the blood vessels either naturally or maybe as a consequence of surgical procedures. This study aims to explore the feasibility of liquid biopsy technique to diagnose prostate cancer.

METHOD

We constructed an assay platform integrating magnetic separation and fluorescence in situ hybridization (FISH) to effectively capture prostate cancer CTCs and evaluate the distribution between healthy volunteers and prostate cancer patients, respectively.

RESULTS

There was a significant difference in the number of CTCs between the healthy population and prostate cancer patients (P < 0.001). The results of the study showed that the CTCs capture identification system has good sensitivity and specificity in identifying prostate cancer patients.

CONCLUSION

The CTCs test allows us to accurately identify patients who are at high risk for prostate cancer, allowing for early intervention and treating patients effectively.

Nanotechnology and machine learning enable circulating tumor cells as a reliable biomarker for radiotherapy responses of gastrointestinal cancer patients

A highly sensitive, circulating tumor cell (CTC)-based liquid biopsy was used to monitor gastrointestinal cancer patients during treatment to determine if CTC abundance was predictive of disease recurrence. The approach used a combination of biomimetic cell rolling on recombinant E-selectin and dendrimer-mediated multivalent immunocapture at the nanoscale to purify CTCs from peripheral blood mononuclear cells. Due to the exceptionally high numbers of CTCs captured, a machine learning algorithm approach was developed to efficiently and reliably quantify abundance of immunocytochemically-labeled cells. A convolutional neural network and logistic regression model achieved 82.9% true-positive identification of CTCs with a false positive rate below 0.1% on a validation set. The approach was then used to quantify CTC abundance in peripheral blood samples from 27 subjects before, during, and following treatments. Samples drawn from the patients either prior to receiving radiotherapy or early in chemotherapy had a median 50 CTC ml-1 whole blood (range 0.6-541.6). We found that the CTC counts drawn 3 months post treatment were predictive of disease progression (p = .045). This approach to quantifying CTC abundance may be a clinically impactful in the timely determination of gastrointestinal cancer progression or response to treatment.

Multivalent aptamer nanoscaffold cytosensor for glioma circulating tumor cells during Epithelial-Mesenchymal transition

The key factor that causes glioma invasion and metastasis is circulating tumor cells (CTCs) undergoing epithelial-mesenchymal transition (EMT). Effective analysis of EMT-CTCs can provide an important foundation for early detection and prognosis monitoring of glioma, but the changes in the biomarkers of CTCs in different states of EMT make detection difficult. In this study, we developed a multivalent aptamer nanoscaffold-based electrochemical cytosensor (MAS-cytosensor) to efficiently detect EMT-CTCs. The two chains forming the MAS are composed of a specific aptamer detector, a binding region for DNA self-assembly, and a foothold for interface anchoring. When target CTCs exist, the bisaptamer detector on MAS can sensitively identify CTCs and pull them to the electrode surface, generating electrochemical signals. It has been demonstrated that the MAS-cytosensor can not only detect EMT-CTCs sensitively (detection limit of 6 cells/mL in buffer), but also allows for further downstream analysis after release with high viability. Overall, this cytosensor provides a reliable detection solution for CTCs regardless of their EMT status, and provides an efficient method for in-depth study role of the post-EMT CTCs in clinical application and metastasis mechanisms.

Clinical implications and perspectives of portal venous circulating tumor cells in pancreatic cancer

Despite recent improvements in the diagnosis and treatment of pancreatic cancer (PC), clinical outcomes remain dismal. Moreover, there are no effective prognostic or predictive biomarkers or options beyond carbohydrate antigen 19-9 for personalized and precise treatment. Circulating tumor cells (CTCs), as a member of the liquid biopsy family, could be a promising biomarker; however, the rarity of CTCs in peripheral venous blood limits their clinical use. Because the first venous drainage of PC is portal circulation, the portal vein can be a more suitable location for the detection of CTCs. Endoscopic ultrasound-guided portal venous sampling of CTCs is both feasible and safe. Several studies have suggested that the detection rate and number of CTCs may be higher in the portal blood than in the peripheral blood. CTC counts in the portal blood are highly associated with hepatic metastasis, recurrence after surgery, and survival. The phenotypic and genotypic properties measured in the captured portal CTCs can help us to understand tumor heterogeneity and predict the prognosis of PC. Small sample sizes and heterogeneous CTC detection methods limit the studies to date. Therefore, a large number of prospective studies are needed to corroborate portal CTCs as a valid biomarker in PC.

Circulating tumor cell quantification during abiraterone plus prednisone therapy may estimate survival in metastatic castration-resistant prostate cancer patients

PURPOSE

Circulating tumor cells (CTCs) predict survival in response to different interventions in metastatic castration-resistant prostate cancer (mCRPC) patients. This study aimed to explore the dynamic change in CTCs during abiraterone plus prednisone therapy and its optimal threshold for prognostication in mCRPC patients.

METHODS

CTCs in blood samples from mCRPC patients (N = 98) at baseline and in the 2nd month after abiraterone plus prednisone treatment initiation (M2) were enumerated by using the CellSearch System.

RESULTS

CTCs were detected in 64.8% of mCRPC patients at baseline with a median value (interquartile range) of 2.0 (0.0-4.0). Elevated CTC count was related to visceral metastasis (P = 0.003), high alkaline phosphatase (P = 0.043), and high lactate dehydrogenase (P = 0.007). Baseline CTC ≥ 1 (vs. < 1) was only associated with shortened radiographic progression-free survival (rPFS) (P = 0.043); additionally, baseline CTC ≥ 5 (vs. < 5) was linked with unfavorable rPFS (P = 0.037) and overall survival (OS) (P = 0.021). Following the therapy, CTCs were reduced at M2 (P < 0.001). Notably, CTC ≥ 1 (vs. < 1) (P = 0.002) and CTC ≥ 5 (vs. < 5) (P < 0.001) at M2 were related to shortened rPFS according to the Kaplan‒Meier curves, and they could independently estimate deteriorative rPFS in the multivariate Cox regression (P = 0.043 and P = 0.027, respectively). Similarly, CTC ≥ 1 (vs. < 1) (P = 0.022) and CTC ≥ 5 (vs. < 5) (P = 0.002) at M2 were related to shortened OS, whereas only CTC ≥ 5 (vs. < 5) could independently predict unfavorable OS (P = 0.017).

CONCLUSION

CTC count ≥ 5 at M2 exhibits excellent prognostic value for abiraterone plus prednisone therapy in mCRPC patients.

Hierarchical integration of DNA nanostructures and NanoGold onto a microchip facilitates covalent chemistry-mediated purification of circulating tumor cells in head and neck squamous cell carcinoma

It is well-established that the combined use of nanostructured substrates and immunoaffinity agents can enhance the cell-capture performance of the substrates, thus offering a practical solution to effectively capture circulating tumor cells (CTCs) in peripheral blood. Developing along this strategy, this study first demonstrated a top-down approach for the fabrication of tetrahedral DNA nanostructure (TDN)-NanoGold substrates through the hierarchical integration of three functional constituents at various length-scales: a macroscale glass slide, sub-microscale self-organized NanoGold, and nanoscale self-assembled TDN. The TDN-NanoGold substrates were then assembled with microfluidic chaotic mixers to give TDN-NanoGold Click Chips. In conjunction with the use of copper (Cu)-catalyzed azide-alkyne cycloaddition (CuAAC)-mediated CTC capture and restriction enzyme-triggered CTC release, TDN-NanoGold Click Chips allow for effective enumeration and purification of CTCs with intact cell morphologies and preserved molecular integrity. To evaluate the clinical utility of TDN-NanoGold Click Chips, we used these devices to isolate and purify CTCs from patients with human papillomavirus (HPV)-positive (+) head and neck squamous cell carcinoma (HNSCC). The purified HPV(+) HNSCC CTCs were then subjected to RT-ddPCR testing, allowing for detection of E6/E7 oncogenes, the characteristic molecular signatures of HPV(+) HNSCC. We found that the resulting HPV(+) HNSCC CTC counts and E6/E7 transcript copy numbers are correlated with the treatment responses in the patients, suggesting the potential clinical utility of TDN-NanoGold Click Chips for non-invasive diagnostic applications of HPV(+) HNSCC.

Liquid biopsy by analysis of circulating myeloma cells and cell-free nucleic acids: a novel noninvasive approach of disease evaluation in multiple myeloma

Multiple myeloma (MM) is an incurable hematological cancer with high spatial- and temporal-heterogeneity. Invasive single-point bone marrow sampling cannot capture the tumor heterogeneity and is difficult to repeat for serial assessments. Liquid biopsy is a technique for identifying and analyzing circulating MM cells and cell products produced by tumors and released into the circulation, allowing for the minimally invasive and comprehensive detection of disease burden and molecular alterations in MM and monitoring treatment response and disease progression. Furthermore, liquid biopsy can provide complementary information to conventional detection approaches and improve their prognostic values. This article reviewed the technologies and applications of liquid biopsy in MM.

ZEB1-activated Notch1 promotes circulating tumor cell migration and invasion in lung squamous cell carcinoma

BACKGROUND

Lung squamous cell carcinoma (LUSC) is recognized as the major subtypes of non-small cell lung cancer (NSCLC). Circulating tumor cells (CTCs) are critical players in tumor metastasis. A molecular profiling of CTCs has previously identified notch receptor 1 (Notch1) as an important mediator in NSCLC. Therefore, we investigate Notch1 roles in LUSC and its related mechanisms.

METHODS

The serum levels of Notch1 were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The CTCs isolated from blood samples were characterized via an immunofluorescence method. Cell motion was determined using Transwell chambers. The regulatory relationship between Notch1 and zinc finger E-box-binding homeobox 1 (ZEB1) was verified by chromatin immunoprecipitation (ChIP) and luciferase reporter assays. The protein levels were detected by western blotting.

RESULTS

Higher Notch1 expression in patients with LUSC than that in normal controls was observed. Notch1 knockdown inhibited cell motion and epithelial-mesenchymal transition (EMT). ZEB1 transcriptionally activated Notch1. ZEB1 upregulation exacerbated the malignant phenotypes of CTCs.

CONCLUSION

ZEB1-activated Notch1 promotes malignant phenotypes of CTCs in LUSC and indicates poor prognosis.

Dynamic changes of the EMT spectrum between circulating tumor cells and the tumor microenvironment in human papillomavirus-positive head and neck squamous cell carcinoma

OBJECTIVES

Human papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HNSCC) differs in terms of cellular and molecular biological characteristics from HPV-negative HNSCC. However, differences in circulating tumor cells (CTCs) between HPV-positive and -negative HNSCC remain unclear.

MATERIALS AND METHODS

We first analyzed eight epithelial-mesenchymal transition (EMT)-related genes (VIM, CDH1, CDH2, SNAI1, SNAI2, TWIST1, ZEB1, and ZEB2) using The Cancer Genome Atlas (TCGA) database. Next, we isolated CTCs from patients with HNSCC using CD45-negative selection and expression analysis of epithelial-related genes (EPCAM, EGFR, and MET) by RT-qPCR. CTC-positive samples were further analyzed for EMT-related genes. In addition, we investigated the proportion of circulating T cell subsets and CD38+ T cells using flow cytometry and their involvement in CTCs.

RESULTS

Compared with HPV-negative HNSCC, expression of CDH1, SNAI1, SNAI2, TWIST1, and ZEB1 was downregulated in HPV-positive HNSCC, as determined by TCGA analysis. CTCs were detected in 19 (52.8 %) of 36 HPV-positive and 26 (68.4 %) of 38 HPV-negative patients with HNSCC. EPCAM-positive and MET-positive CTCs were significantly more frequent in patients with HPV-negative HNSCC. HPV-positive patients with HNSCC exhibited significantly high SNAI1 and ZEB2 expression in CTCs. Interestingly, differences in SNAI1 expression levels differed markedly between CTCs and TCGA based on HPV status. Moreover, HPV-positive patients with HNSCC exhibiting SNAI1-high CTCs showed a superior prognosis and a lower proportion of CD38+ T cells than those with SNAI1-low CTCs.

CONCLUSION

Our results provide novel insights into the EMT-MET spectrum of CTCs and may contribute to the development of prognostic biomarkers for HPV-positive HNSCC.

Improved platform for breast cancer circulating tumor cell enrichment and characterization with next-generation sequencing technology

Circulating tumor cells (CTCs) represent cells shed from the primary tumor or metastatic sites and can be used to monitor treatment response and tumor recurrence. However, CTCs circulate in extremely low numbers making in-depth analysis beyond simple enumeration challenging when collected from peripheral blood. Furthermore, tumor heterogeneity, a hallmark of many tumors, especially breast cancer, further complicates CTC characterization. To overcome this limitation, we developed a platform based on the large-scale isolation of CTCs by apheresis, allowing us to collect CTCs in large numbers, which were preserved live in liquid nitrogen for further characterization. Flow cytometry followed by cell sorting (FACS) was performed using a combination of antibodies directed against cell surface markers of white blood cells (CD45) and epithelial tumor cells (CK8). Analysis of subpopulations CD45+/- and CK8+/- by bulk RNA sequencing (RNAseq) and the CD45-/CK8 positive population by single-cell RNAseq was performed. The CD45- population was enriched using CD45 magnetic beads separation and examined by IHC for pan-cytokeratin and immunofluorescence (IF) for specific markers, including the elusive circulating cancer stem cells (CSCs). CSC-rich mammospheres were grown in vitro for further analysis and treated to examine their response to chemotherapeutic agents. Finally, mammospheres were transplanted into the mammary fat pad and bone of immunodeficient mice to examine tumor growth in vivo. This platform enables the detection and collection of CTCs in early and late-stage breast cancer patients of every subtype. Markers including CD44/24, ALDH1 and CXCR4 were identified by IF and showed high expression following mammosphere culture, which responded predictably to chemotherapeutic agents. Mammospheres were also transplanted into nude mice and induced tumors in the mammary fat pad and bone following intra-tibial transplantation. Finally, bulk RNA analysis of the FACS isolated CD45+/- and CK8+/- cells showed a clear separation of CD45- away from CD45+ populations. Single-cell RNAseq of the FACS isolated CD45-/CK8+ cells showed the presence of 4-5 clusters, confirming the high degree of heterogeneity of CTCs. Our platform for large-scale isolation of CTCs using apheresis is suitable for an in-depth analysis of the cancer phenotype and may eventually allow evaluation in real-time of the disease process to optimize cancer regimens.

Size-Based Method for Enrichment of Circulating Tumor Cells from Blood of Colorectal Cancer Patients

Circulating tumor cells (CTCs) are precursors of the metastatic cascade, which is responsible for 90% of all cancer-related deaths. CTCs arise from solid tumors and travel through the bloodstream and lymphatic system. Developments in the isolation and analysis of CTCs promise potential biomarker assays for detection and monitoring of cancer through a minimally invasive procedure. Despite this, the precise role of CTCs in metastasis remains poorly characterized, mainly due to the low density of CTCs (1-10 CTCs per 10 mL of blood) present in patient blood and the lack of robust methods for their isolation in a standard laboratory setting. CellSearch is currently the only FDA-approved CTC enrichment protocol, but limitations of this EpCAM-based method include cost, availability, and the use of a single surface marker for capture. To address these limitations, we have optimized an existing method, MetaCell, which exploits the differences in size of CTCs compared to other blood cells for CTC enrichment from blood. MetaCell contains a membrane with 8 μm pores, and blood is filtered through this kit by capillary action and CTCs, which are typically larger than the pores and remain on top of the membrane, while most leukocytes pass through the pores. The membrane along with these CTCs can be detached and transferred to 6-well plates for culturing or directly used for characterization. Here, we provide a detailed protocol for enrichment of CTCs using the filtration device MetaCell and a procedure for characterization of CTCs by immunohistochemical staining.

The Protocol of Circulating Tumor Cell Detection

The detection of CTCs is related to the development of tumors and can be used in medical fields such as early diagnosis, postoperative evaluation, monitoring treatment, and predicting disease prognosis. This article focuses on the entire process of CTC detection, including negative enrichment isolation and immunofluorescence in situ hybridization detection.

Folate receptor-positive circulating tumor cells in predicting ground-glass nodules malignancy

OBJECTIVE

To study the clinical significance of folate receptor-positive circulating tumor cells (FR+CTCs) in determining malignancy of ground-glass nodules (GGNs) and assess the added value of FR+CTC in the classic GGN evaluation model (Mayo Model).

METHODS

Sixty-five patients with single indeterminate GGN were recruited. Twenty-two participants had benign/pre-malignant diseases, and forty-three had lung cancers, as confirmed by histopathology examination. FR+CTC was enumerated by CytoploRare^® Kit. A CTC model was drawn based on the multivariate logistic analysis. The area under the receiver operating characteristic curve (AUC) was analyzed to evaluate the diagnostic performance of FR+CTC, CTC model and Mayo model.

RESULTS

In the cohort, the mean age of 13 males and 9 females with benign/pre-malignant diseases was 57.7 ± 10.2 years. The mean age of 13 males and 30 females with lung cancers was 53.8 ± 11.7 years. There was no significant difference between the age and the smoking history (P=0.196 and P=0.847, respectively). FR+CTC can effectively differentiate lung cancer from benign/pre-malignant diseases [sensitivity: 88.4%, specificity: 81.8%, the AUCs was 0.8975, 95% confidence interval (CI): 0.8174-0.9775] in patients with GGN. Multivariate analysis revealed that FR+CTC level, tumor size, and tumor location were independent predictors of GGN malignancy (P<0.05). The prediction model based on these factors showed better diagnostic efficiency than the Mayo model (AUC: 0.9345 vs. 0.6823), yielding superior sensitivity (81.4% vs. 53.5%) and specificity (95.5% vs. 86.4%).

CONCLUSION

The FR+CTC exhibited a promising potential in determining the malignancy of indeterminate GGNs, and the CTC model's diagnostic efficiency was superior to the Mayo model.

Clinical significance of circulating tumor cell (CTC)-specific microRNA (miRNA) in breast cancer

As a noninvasive method, circulating tumor cell (CTC) provides ideal liquid biopsy specimens for early cancer screening and diagnosis. CTCs detection in breast cancer is correlated with patient prognosis such as disease-free survival (DFS) and overall survival (OS). Besides, accumulating evidence supported that CTCs count may be indicator for chemotherapy response as well. The functional roles of microRNA (miRNA) in breast cancer have been well-recognized for the last few years. Due to its stability in circulation, numerous studies have proven that circulating miRNA may serve as promising diagnostic and prognostic biomarkers in breast cancer. The potential ability of miRNAs in disease screening, staging or even molecular subtype classification makes them valuable tools for early breast cancer patients. It would be of great significance to characterize the miRNA expression profile in CTCs, which could provide reliable biological information originated from tumor. However, some issues need to be addressed before the utility of CTC-specific miRNAs in clinical setting. Taken together, we believe that CTC-specific miRNA detection will be trend for early breast cancer screening, diagnosis and treatment monitor in near future.

Metabolomic analysis of circulating tumor cells derived liver metastasis of colorectal cancer

Metabolic reprogramming is one of the essential features of tumor that may dramatically contribute to metastasis and collapse. The metabolic profiling is investigated on the patient derived tissue and cancer cell line derived mouse metastasis xenograft. As well-recognized "seeds" for remote metastasis of tumor, role of circulating tumor cells (CTCs) in the study of metabolic reprogramming feature of tumor is yet to be elucidated. More specifically, whether there is difference of metabolic features of liver metastasis in colorectal cancer (CRC) derived from either CTCs or cancer cell line is still unknown. In this study, comprehensive untargeted metabolomics was performed using high performance liquid chromatography-mass spectrometry (HPLC-MS) in liver metastasis tissues from CT26 cells and CTCs derived mouse models. We identified 288 differential metabolites associated with the pathways such as one carbon pool by folate, folate biosynthesis and histidine metabolism through bioinformation analysis. Multiple gene expression was upregulated in the CTCs derived liver metastasis, specifically some specific enzymes. These results indicated that the metabolite phenotype and corresponding gene expression in the CTCs derived liver metastasis tissues was different from the parental CT26 cells, displaying a specific up-regulation of mRNAs involved in the above metabolism-related pathways. The metabolic profile of CTCs was characterized on the liver metastatic process in colorectal cancer. The invasion ability and chemo drug tolerance of the CTCs derived tumor and metastasis was found to be overwhelming higher than cell line derived counterpart. Identification of the differential metabolites will lead to a better understanding of the hallmarks of the cancer progression and metastasis, which may suggest potential attractive target for treating metastatic CRC.

A universal monoclonal antibody-aptamer conjugation strategy for selective non-invasive bioparticle isolation from blood on a regenerative microfluidic platform

Simultaneous isolation of various circulating tumor cell (CTC) subtypes from whole blood is useful in cancer diagnosis and prognosis. Microfluidic affinity separation devices are promising for CTC separation because of their high throughput capacity and automatability. However, current affinity agents, such as antibodies (mAbs) and aptamers (Apts) alone, are still suboptimal for efficient, consistent, and versatile cell analysis. By introducing a hybrid affinity agent, i.e., an aptamer-antibody (Apt-mAb) conjugate, we developed a universal and regenerative microchip with high efficiency and non-invasiveness in the separation and profiling of various CTCs from blood. The Apt-mAb conjugate consists of a monoclonal antibody that specifically binds the target cell receptor and a surface-bound aptamer that recognizes the conserved Fc region of the mAb. The aptamer then indirectly links the surface functionalization of the microfluidic channels to the mAbs. This hybrid affinity agent and the microchip platform may be widely useful for various bio-particle separations in different biological matrices. Further, the regeneration capability of the microchip improves data consistency between multiple uses and minimizes plastic waste while promoting environmental sustainability. STATEMENT OF SIGNIFICANCE: A hybrid affinity agent, Apt-mAb, consisting of a universal aptamer (Apt) that binds the conserved Fc region of monoclonal antibodies (mAbs) was developed. The invented nano-biomaterial combines the strengths and overcomes the weakness of both Apts and mAbs, thus changing the paradigm of affinity separation of cell subtypes. When Apt-mAb was used to fabricate microfluidic chips using a "universal screwdriver" approach, the microchip could be easily tuned to bind any cell type, exhibiting great universality. Besides high sensitivity and selectivity, the superior regenerative capacity of the microchips makes them reusable, which provides improved consistency and repeatability in cell profiling and opens a new approach towards in vitro diagnostic point-of-care testing devices with environmental sustainability and cost-effectiveness.

Potential values of circulating tumor cell for detection of recurrence in patients of thyroid cancer: a diagnostic meta-analysis

Background

Several studies have reported that circulating tumor cells (CTCs) are a promising marker for the diagnosis of thyroid cancer (TC) with recurrence or distant metastasis (DMs). However, some studies emerged with conflicting results. Therefore, we provide a meta-analysis to evaluate the diagnostic performance of CTC for detection of recurrence in patients of TC.

Methods

We searched PubMed, Web of Science, Cochrane library with the keywords “thyroid cancer” and “circulating tumor cells”. Data extraction and risk of bias assessment were performed independently by two reviewers. The summary receiver operating characteristic curve (SROC) and other parameters were adopted to summarize the overall test performance. The sensitivity of CTCs in the detection of recurrent TC was reviewed. All analyses were performed by STATA 12.0 and Meta-disc software.

Results

For CTCs expressing epithelial cell adhesion molecule (EpCAM), seven studies were included in our meta-analysis. Pooled sensitivity, specificity, and diagnostic odds ratio were 0.71 (95% CI: 0.63–0.78), 0.89 (95% CI: 0.84–0.94), and 26.75 (95% CI: 9.11–78.53); 0.78 (95% CI: 0.65–0.89), 0.88 (95% CI: 0.76–0.96), and 40.01 (95% CI: 10.49–152.63) for CTCs expressing thyroid stimulating hormone receptor (TSHR). The area under the SROC for EpCAM and TSHR were both 0.91.

Conclusion

CTC was a reliable marker for the diagnosis of TC patients with recurrence and DMs, and the sensitivity of CTCs expressing TSHR was higher than that of EpCAM. Additional research is warranted in order to establish uniformity in international guidelines, make up the drawbacks of conventional diagnostic methods and to prevent futile surgery.

A liquid-crystal aptasensing platform for label-free detection of a single circulating tumor cell

Circulating tumor cells (CTCs), which are shed from a primary site into the bloodstream and lead to distal metastases, are pivotal as a prognostic marker for evaluating the treatment response of cancer patients. One of the major challenges of detecting CTCs is their scarcity in blood. We report herein a label-free liquid crystal (LC) cytosensor by adopting an aptamer against epithelial cell adhesion molecule (EpCAM) to capture EpCAM-positive cancer cells. The optical and dielectric signals transduced from the interaction between LC and different numbers of captured breast cancer cells were investigated. A limit of detection (LOD) of 5 CTCs was resulted from the optical biosensing approach relying on texture observation and image analysis of the optical signal in polarizing micrographs. The LOD was further lowered to a single CTC in the dielectric approach by studying the real- and imaginary-part dielectric constants of LC at 1 kHz and 30 Hz as well as the relaxation frequency. The LC-based EpCAM-specific dielectric cytosensor was successfully applied to single-cell CTC detection in cancer cell-spiked human serum and whole blood. This platform demonstrates the potential of LC-based biosensing technologies in cellular-level detection and quantitation, which is crucial to the early diagnosis of cancer metastasis and progression.

Sensitive CTC analysis and dual-mode MRI/FL diagnosis based on a magnetic core-shell aptasensor

Synergizing the sensitive circulating tumor cell (CTC) capture, detection, release and the specific magnetic resonance/fluorescence (MR/FL) imaging for accurate cancer diagnosis is of great importance for cancer treatment. Herein, EcoR1-responsive complementary pairing of two ssDNA with a fluorescent P₀ aptamer, which can specifically bind with the overexpressed MUC1 protein on cancer cells, was covalently modified to SiO₂@C-coated magnetic nanoparticles for preparing a special nanoparticle-mediated FL turn-on aptasensor (FSC-D-P₀). This aptasensor can selectively capture/enrich CTC and thus achieve sensitive CTC detection/imaging in even the blood due to its stable targeting, unique magnetic properties and the regulated interactions between the quencher and the fluorescent groups. Meanwhile, FSC-D-P₀ can release the captured CTC for further downstream analysis upon the EcoR1 enzyme-triggered cleavage of the double-stranded DNA (dsDNA). Most importantly, this aptasensor can distinctly avoid false positivity of MRI via multiple targeting mechanisms. Thus, the sensitive CTC capture, detection, release and accurate MR/FL imaging were synergistically combined into a single platform with good biocompatibility, promising a robust pattern for clinical tumor diagnosis in vitro and in vivo.

[A Rare Case of Extremely High Counts of EpCAM + Circulating Tumor Cells and Circulating Tumor Microemboli Detected in a Patient with Small Cell Lung Cancer]

A 77-year-old man was admitted at our hospital due to "generalized increase in the number of masses and enlargement of the masses observed for one month". Combined assessment of the imaging (computed tomography and magnetic resonance imaging) findings and results of lung centesis biopsy and liquid biopsy suggest that the patient had small cell lung cancer of the left upper lobe, with right hilar, mediastinal, bilateral axillary, abdominal and retroperitoneal lymph node metastases, as well as widespread subcutaneous soft tissue, liver, bilateral adrenal, bilateral kidneys and multiple brain metastases (extensive stage). In order to obtain an evaluation of the development of the disease as soon as possible, the circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) in 6 mL peripheral blood were examined by subtraction enrichment-immunostaining fluorescence in situ hybridization (SE-iFISH) technology. A total of 919 epithelial cell adhesion molecule (EpCAM)-positive CTCs and 61 EpCAM-positive CTM were identified. Among them, there were 14 haploid CTCs (1.52%), 788 diploid CTCs (85.75%), 44 triploid CTCs (4.79%), 70 tetraploid CTCs (7.62%) and 3 pentaploid or higher-fold polyploid CTCs (0.33%). Herein, we reported a rare case with extremely high accounts of CTCs and CTM and positive findings for tumor markers, which was identified for the first time. The examination of CTCs by SE-iFISH contributed to the diagnosis, prognosis and treatment evaluation of cancer and facilitated the formulation of precise and individualized therapeutic regime.

Identification of the target protein of the metastatic colorectal cancer-specific aptamer W3 as a biomarker by aptamer-based target cells sorting and functional characterization

Metastasis is a leading cause of cancer-related deaths. Hence, the discovery of more reliable metastasis-related biomarkers is crucial to improve the survival rate of cancer patients. W3 is an aptamer previously produced by the subtractive cell-SELEX using metastatic colorectal cancer cells as target cells and non-metastatic cells as negative cells. In this study, we aimed to evaluate whether the target molecule of W3 can potentially act as a metastatic biomarker. First, we obtained two cell subpopulations with different expression levels of the target molecule by W3-based cell sorting. Subsequently, we demonstrated that W3^high cells have a higher metastatic potential than W3^low cells both in vitro and in vivo. Further, immunohistochemical analysis revealed that W3 target expression is positively associated with metastasis and poor prognosis of CRC patients. Using mass spectrometry (MS) combined with pull-down, we identified that Ephrin type-A receptor 2 (EphA2) is the target of W3. EphA2's potential as a metastatic predictor was demonstrated by capturing W3-positive circulating tumor cells from CRC patients using a W3 probe. Based on these results, we put forward a stratagem for cell-SELEX-based biomarker discovery: selecting an aptamer through subtractive cell-SELEX towards the phenotype of interest; evaluating the functional phenotype of the target molecule by aptamer-based target cell sorting and analysis of clinical samples; and identifying the aptamer's target molecule using MS and aptamer-based target enrichment. This stratagem not only shortens the time for the clinical application of aptamers but also enables a more targeted and efficient discovery of biomarkers.

Circulating tumor cells and cell-free tumor DNA analyses in urothelial cancer using the LiquidBiopsy platform

Background

Emerging data suggested that liquid biopsy such as detection of circulating tumor cells (CTCs) and cell-free tumor DNA analysis augments the management of patients with urothelial cancer (UC). We presented our pilot experience of liquid biopsy using the Ion Torrent platform to detect CTCs and genomic alterations in UC.

Materials and methods

Blood or urine samples from 16 patients were subjected to CTC and plasma/urine cell-free tumor DNA isolation for next generation sequencing (NGS) using the Ion S5 system to detect mutations among 50 oncogenes on the Ion AmpliSeq Cancer Hotspot Panel.

Results

The Ion Torrent platform detected a higher number of CTCs than those in previous studies using the CellSearch^TM system. Overall, mutations were detected in 13/16 (81.3%) patients with a median number of 18 (range 12-25). NGS isolated 17 hotspot mutations from 11 genes and 41 novel genomic alterations from 24 genes, some of which are supposed to be clinically actionable.

Conclusions

The Ion Torrent platform efficiently detected CTCs compared with previous reports. NGS with the present system also allowed for detection of gene alterations which are likely to be therapeutic targets and provided an attractive tool to guide personalized therapy for patients with advanced UC.

Fluid shear stress regulates the survival of circulating tumor cells via nuclear expansion

Distant metastasis mainly occurs through hematogenous dissemination, where suspended circulating tumor cells (CTCs) experience a considerable level of fluid shear stress. We recently reported that shear flow induced substantial apoptosis of CTCs, although a small subpopulation could still persist. However, how suspended tumor cells survive in shear flow remains poorly understood. This study finds that fluid shear stress eliminates the majority of suspended CTCs and increases nuclear size, whereas it has no effect on the viability of adherent tumor cells and decreases their nuclear size. Shear flow promotes histone acetylation in suspended tumor cells, the inhibition of which using one drug suppresses shear-induced nuclear expansion, suggesting that shear stress might increase nuclear size through histone acetylation. Suppressing histone acetylation-mediated nuclear expansion enhances shear-induced apoptosis of CTCs. These findings suggest that suspended tumor cells respond to shear stress through histone acetylation-mediated nuclear expansion, which protects CTCs from shear-induced destruction. Our study elucidates a unique mechanism underlying the mechanotransduction of suspended CTCs to shear flow, which might hold therapeutic promise for CTC eradication.

Analytical validation and initial clinical testing of quantitative microscopic evaluation for PD-L1 and HLA I expression on circulating tumor cells from patients with non-small cell lung cancer

INTRODUCTION

PD-L1 expression in non-small cell lung cancer (NSCLC) predicts response to immune checkpoint blockade, however is an imperfect biomarker given tumor heterogeneity, and the antigen presentation pathway requiring other components including HLA I expression. HLA I downregulation may contribute to resistance, warranting its evaluation in attempts to guide patient selection. In addition, earlier detection of acquired resistance could prompt earlier change in treatment and prolong patient survival. Analysis of circulating tumor cells (CTCs) captures heterogeneity across multiple sites of metastases, enables detection of changes in tumor burden that precede radiographic response, and can be obtained in serial fashion.

METHODS

To quantify the expression of both PD-L1 and HLA I on CTCs, we developed exclusion-based sample preparation technology, achieving high-yield with gentle magnetic movement of antibody-labeled cells through virtual barriers of surface tension. To achieve clinical-grade quantification of rare cells, we employ high quality fluorescence microscopy image acquisition and automated image analysis together termed quantitative microscopy.

RESULTS

In preparation for clinical laboratory implementation, we demonstrate high precision and accuracy of these methodologies using a diverse set of control materials. Preliminary testing of CTCs isolated from patients with NSCLC demonstrate heterogeneity in PD-L1 and HLA I expression and promising clinical value in predicting PFS in response to PD-L1 targeted therapies.

CONCLUSIONS

By confirming high performance, we ensure compatibility for clinical laboratory implementation and future application to better predict and detect resistance to PD-L1 targeted therapy in patients with NSCLC.

HepT1-derived murine models of high-risk hepatoblastoma display vascular invasion, metastasis, and circulating tumor cells

Hepatoblastoma (HB) is the most common pediatric primary liver malignancy, and survival for high-risk disease approaches 50%. Mouse models of HB fail to recapitulate hallmarks of high-risk disease. The aim of this work was to generate murine models that show high-risk features including multifocal tumors, vascular invasion, metastasis, and circulating tumor cells (CTCs). HepT1 cells were injected into the livers or tail veins of mice, and tumor growth was monitored with magnetic resonance and bioluminescent imaging. Blood was analyzed with fluorescence-activated cell sorting to identify CTCs. Intra- and extra-hepatic tumor samples were harvested for immunohistochemistry and RNA and DNA sequencing. Cell lines were grown from tumor samples and profiled with RNA sequencing. With intrahepatic injection of HepT1 cells, 100% of animals grew liver tumors and showed vascular invasion, metastasis, and CTCs. Mutation profiling revealed genetic alterations in seven cancer-related genes, while transcriptomic analyses showed changes in gene expression with cells that invade vessels. Tail vein injection of HepT1 cells resulted in multifocal, metastatic disease. These unique models will facilitate further meaningful studies of high-risk HB.

This article has an associated First Person interview with the first author of the paper.

Summary: In this work, we developed and thoroughly characterized several unique models of hepatoblastoma derived from the HepT1 cell line that show high-risk features.

Recent clinical research on the application of liquid biopsy in neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in children and has the features of high recurrence rate and low survival rate, and therefore, early diagnosis, treatment response evaluation, and recurrence monitoring are of great significance for NB patients. Liquid biopsy refers to the detection of cells and nucleic acids in fluid specimens, mainly blood. It is noninvasive and can overcome tumor heterogeneity, thus making it possible to achieve the early diagnosis and dynamic detection of NB. This review introduces the latest advances in clinical research on the application of liquid biopsy in NB.

Adapted suspension tumor cells rewire metabolic pathways for anchorage-independent survival through AKT activation

Metastatic spread of cancer cells is the main cause of cancer-related death. As cancer cells adapt themselves in a suspended state in the blood stream before penetration and regrowth at distal tissues, understanding their survival strategy in an anchorage-independent condition is important to develop appropriate therapeutics. We have previously generated adapted suspension cells (ASCs) from parental adherent cancer cells to study the characteristics of circulating tumor cells. In this study, we explored metabolic rewiring in MDA-MB-468 ASCs to adapt to suspension growth conditions through extracellular flux analyses and various metabolic assays. We also determined the relationship between AKT activation and metabolic rewiring in ASCs using the AKT inhibitor, MK2206. ASCs reprogramed metabolism to enhance glycolysis and basal oxygen consumption rate. RNA-sequencing analysis revealed the upregulation in the genes related to glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation. The changes in the metabolic program led to a remarkable dependency of ASCs on carbohydrates as an energy source for proliferation as compared to parental adherent cells (ADs). AKT activation was observed in ASCs and those generated from pancreatic and other breast cancer cells, and AKT activation inhibition in ASCs decreased glycolysis and oxygen consumption. AKT activation is an important strategy for obtaining energy through the enhancement of glycolysis in ASCs. The regulation of AKT activity and/or glycolysis may provide a strong therapeutic strategy to prevent the metastatic spread of cancer cells.

Development of a Multi-target Protein Biomarker Assay for Circulating Tumor Cells

We report a highly sensitive and selective CNT-switch liquid biopsy platform that detects and quantifies protein biomarker expressions from circulating tumor cells in blood for early detection of metastatic breast cancer and its relapse. This platform first isolates and enriches more than 99% of tumor cells with an off-chip micro-size membrane filtration technique and then conducts on-chip detection of the membrane and internal protein biomarkers of the tumor cells with high sensitivity and selectivity. High sensitivity is achieved with complete association of the antibody-antigen-antibody (Ab-Ag-Ab) complex by precisely and rapidly assembling carbon nanotubes (CNTs) across two parallel electrodes via sequential DC electrophoresis and dielectrophoresis (DEP) deposition. Each bridged CNT acts as a switch that connects the electrodes and closes the circuit to generate an electrical signal. The high selectivity is achieved with a critical hydrodynamic shear rate that irreversibly removes non-target linkers of the aligned CNTs. At present, we are able to detect the protein biomarkers from 5 spiked breast cancer tumor cells of different types within 7.5 ml of human blood samples. This demonstrates the potential of this platform as an inexpensive and noninvasive alternative to MRI scans and tissue biopsies currently used to detect early metastatic breast cancer and its relapse.

Place des biopsies liquides dans le diagnostic et la caractérisation moléculaire des cancers du sein: Role of liquid biopsies in the diagnosis and molecular characterization of breast cancer

The tumor biopsy remains essential for breast cancer diagnosis and characterization. Indeed, the treatment is decided according to histological subtype, and according to the presence of targetable molecular alterations. Notably, the presence of hormone receptors, ERBB2 hyperexpression or the existence of PIK3CA or ESR1 mutations are among the alterations commonly investigated. But these biological characteristics are determined only partially by tumor biopsy, due to tumor heterogeneity or tumor plasticity that happens spontaneously or under treatment. Liquid biopsy, and in particular circulating tumor DNA and circulating tumor cells, is a non-invasive method to identify and characterize the presence of cancer in the blood. The aim of this review is to determine the value of liquid biopsy to enhance or replace the data provided by a tumor biopsy.

Negative-Selection Enrichment of Circulating Tumor Cells from Peripheral Blood Using the Microfluidic CTC-iChip

The ability to isolate and analyze rare circulating tumor cells (CTCs) holds the potential to increase our understanding of cancer evolution and allows monitoring of disease and therapeutic responses through a relatively non-invasive blood-based biopsy. While many methods have been described to isolate CTCs from the blood, the vast majority rely on size-based sorting or positive selection of CTCs based on surface markers, which introduces bias into the downstream product by making assumptions about these heterogenous cells. Here we describe a negative-selection protocol for enrichment of CTCs through removal of blood components including red blood cells, platelets, and white blood cells. This procedure results in a product that is amenable to downstream single-cell analytics including RNA-Seq, ATAC-Seq and DNA methylation, droplet digital PCR (ddPCR) for tumor specific transcripts, staining and extensive image analysis, and ex vivo culture of patient-derived CTCs.

Improving the diagnosis of prostate cancer by telomerase-positive circulating tumor cells: A prospective pilot study

BACKGROUND

Prostate-specific antigen (PSA) testing is limited in identifying prostate cancer (PCa) with modestly elevated PSA levels. Therefore, a robust method for the diagnosis of PCa is urgently needed.

METHODS

A total of 203 men with a PSA level of ≥4 ng/ml were eligible for enrollment in this study from July 2018 to May 2021, and randomly divided into a training set (n=78) and a validation set (n=125). Circulating tumor cells (CTCs) were detected using telomerase-based CTC detection (TBCD), and the diagnostic ability was evaluated using receiver operating characteristic (ROC) and logistic regression analyses.

FINDINGS

In the training set, the area under the curve (AUC) of CTCs was 0.842 with a sensitivity of 80.33% and specificity of 82.35%. In the validation set, the AUC of CTCs was 0.789, with a sensitivity of 79.31% and specificity of 81.58%. There was no significant difference between CTCs (AUC=0.793) and PSA (AUC=0.697) in the range of 4-50 ng/ml. In the ranges of 4-20 ng/ml and 4-10 ng/ml, the AUC of CTCs were 0.811 and 0.825, respectively, which were superior to the AUC of PSA (0.588 and 0.541). The sensitivity and specificity of CTCs in the three PSA groups were higher than 80%. Moreover, we further established a CTC+PSA combined model, which could significantly improve the diagnostic ability of a PSA level of '4-10 ng/ml'.

INTERPRETATION

TBCD could be a valuable method for distinguishing PCa and benign prostatic disease, especially in the PSA diagnostic gray area of '4-10 ng/ml'.

Circulating tumor cells in patients undergoing androgen deprivation therapy with versus without cryosurgery for metastatic prostate cancer: a retrospective analysis

BACKGROUND

The study aimed to assess the value of circulating tumor cells (CTCs) as a prognostic and treatment response marker in patients undergoing androgen deprivation therapy (ADT) plus cryosurgery vs. ADT alone for metastatic prostate cancer (mPCA).

METHODS

This retrospective analysis included 43 patients with mPCA: 23 receiving ADT alone (control) and 20 receiving additional cryosurgery (cryosurgery group). CTCs and progression-free survival (PFS) were compared between the two groups. Cox proportional hazards regression was conducted to identify variables associated with PFS.

RESULTS

Median PFS was 35 months (IQR, 33‑37) in the cryosurgery group vs. 30 months (IQR, 27‑32) in the control (p < 0.001). CTCs count was significantly lower in the cryosurgery group at both 3 months (z = 2.170, p = 0.030) and 12 months (z = 2.481; p = 0.013). In comparison to the baseline, the number of CTCs at both 3 and 12 months was lower in the cryosurgery group (p = 0.004 and p < 0.001, respectively), but not in the ADT alone group. In multivariate Cox regression, shorter PFS was associated with baseline PSA ≧100 ng/ml (HR 6.584, 95% CI, 5.309‑8.166), biopsy Gleason score ≧ 8 (HR 2.064, 95% CI, 1.608‑2.650), clinic T stage>T2b (HR 5.021, 95% CI, 3.925‑6.421), number of bone metastases>3 (HR 3.421, 95% CI, 2.786‑4.202), positive CTCs at 3 months post-treatment (HR 6.833, 95% CI, 5.176‑9.022), positive CTCs 1 year post-treatment (HR 6.051, 95% CI, 4.347‑8.424). Prostate cryosurgery was associated with longer PFS (HR 0.062, 95% CI, 0.048‑.080).

CONCLUSIONS

CTC was a prognostic and treatment response marker for mPCA. ADT plus cryosurgery could reduce CTCs and prolong PFS vs. ADT alone in mPCA patients with low metastatic volume.

A new insight to deformability correlation of circulating tumor cells with metastatic behavior by application of a new deformability-based microfluidic chip

Isolation and characterization of circulating tumor cells (CTCs) found in blood samples of cancer patients have been considered as a reliable source for cancer prognosis and diagnosis. A new continuous microfluidic platform has been designed in this investigation for simultaneous capture and characterization of CTCs based on their deformability. The deformability-based chip (D-Chip) consists of two sections of separation and characterization where slanted weirs with a gap of 7 μm were considered. Although sometimes CTCs and leukocytes have the same size, the deformability differs in such a way that can be exploited for enrichment purposes. MCF7 and MDA-MB-231 cell lines were used for the initial evaluation of the D-Chip performance. In the separation section, cancer cells were isolated based on deformability differences with an efficiency of higher than 93% (∼average capturing capacity of 2085 out of 2200 cancer cells ml^-1) and with significantly high purity (15-40 WBCs ml^-1; ∼5 log depletion of WBCs). Cancer cells were categorized based on the deformability difference in the characterization section. Subsequently, 15 clinical blood samples from breast cancer patients were analyzed by the D-Chip. Suggest 'The chip detected CTCs in all patient samples, processed the blood sample at a high throughput of 5.3 ml/h, and properly categorized CTCs based on deformability differences. Further characterization showed that the highly deformable breast cancer CTCs in our patient samples also showed higher potential of metastasis in support of a broader correlation between deformability of CTCs and metastatic behavior.

Detection and clinical significance of circulating tumor cells in colorectal cancer

Histopathological examination (biopsy) is the "gold standard" for the diagnosis of colorectal cancer (CRC). However, biopsy is an invasive method, and due to the temporal and spatial heterogeneity of the tumor, a single biopsy cannot reveal the comprehensive biological characteristics and dynamic changes of the tumor. Therefore, there is a need for new biomarkers to improve CRC diagnosis and to monitor and treat CRC patients. Numerous studies have shown that "liquid biopsy" is a promising minimally invasive method for early CRC detection. A liquid biopsy mainly samples circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), microRNA (miRNA) and extracellular vesicles (EVs). CTCs are malignant cells that are shed from the primary tumors and/or metastases into the peripheral circulation. CTCs carry information on both primary tumors and metastases that can reflect dynamic changes in tumors in a timely manner. As a promising biomarker, CTCs can be used for early disease detection, treatment response and disease progression evaluation, disease mechanism elucidation, and therapeutic target identification for drug development. This review will discuss currently available technologies for plasma CTC isolation and detection, their utility in the management of CRC patients and future research directions.

Liquid Biopsy in Metastatic Breast Cancer: Current Role of Circulating Tumor Cells and Circulating Tumor DNA

BACKGROUND

In metastatic breast cancer (MBC), blood-based diagnostics have become a major focus of oncological research in the last 2 decades. Detection of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) has the potential to improve prognosis assessment and complement standard therapy monitoring tools.

SUMMARY

To date, several large analyses have confirmed high CTC counts as an independent prognostic factor. Persistently high CTC numbers during systemic treatment are associated with early progression, but it remains to be clarified which therapeutic options should be offered to such patients since the SWOG 0500 trial failed to show benefit from early switch to another chemotherapy regimen in patients with CTC persistence. In comparison, evidence on the prognostic value of ctDNA is still limited. Most importantly, liquid biopsy-guided treatment interventions have been investigated in several trials. In patients with hormone receptor-positive and HER2-negative MBC, CTC-driven therapy choices resulted in similar PFS to physician's choice treatment. Recently, the DETECT III trial has shown that patients with HER2-negative MBC and HER2-positive CTCs may benefit from targeted anti-HER2 treatment with lapatinib. ctDNA-driven therapy selection has already been approved in clinical routine: alpelisib is the first targeted treatment indicated on the basis of a ctDNA test. Key Messages: CTCs and ctDNA predict clinical outcome and have a potential to improve therapy choices in MBC.

Cell-free DNA and circulating tumor cell kinetics in a pre-clinical head and neck Cancer model undergoing radiation therapy

BACKGROUND

Monitoring circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), known as liquid biopsies, continue to be developed as diagnostic and prognostic markers for a wide variety of cancer indications, mainly due to their minimally invasive nature and ability to offer a wide range of phenotypic and genetic information. While liquid biopsies maintain significant promising benefits, there is still limited information regarding the kinetics of ctDNA and CTCs following radiation therapy which remains a vital treatment modality in head and neck cancers. This study aims to describe the kinetics of ctDNA and CTCs following radiation exposure in a preclinical rabbit model with VX2 induced buccal carcinoma.

METHODS

Seven rabbits were inoculated with VX2 cells in the buccal mucosa and subjected to radiation. At selected time points, blood sampling was performed to monitor differing levels of ctDNA and CTC. Plasma ctDNA was measured with quantitative PCR for papillomavirus E6 while CTCs were quantified using an immunomagnetic nanoparticles within a microfluidic device. Comparisons of CTC detection with EpCAM compared to multiple surface markers (EGFR, HER2 and PSMA) was evaluated and correlated with the tumor size.

RESULTS

Plasma ctDNA reflects the overall tumor burden within the animal model. Analysis of correlations between ctDNA with tumor and lymph node volumes showed a positive correlation (R = 0.452 and R = 0.433 [p < 0.05]), respectively. Over the course of treatment, ctDNA levels declined and quickly becomes undetectable following tumor eradication. While during the course of treatment, ctDNA levels were noted to rise particularly upon initiation of radiation following scheduled treatment breaks. Levels of CTCs were observed to increase 1 week following inoculation of tumor to the primary site. For CTC detection, the use of multiple surface markers showed a greater sensitivity when compared to detection using only EpCAM. Plasma CTC levels remained elevated following radiation therapy which may account for an increased shedding of CTCs following radiation.

CONCLUSION

This study demonstrates the utility of ctDNA and CTCs detection in response to radiation treatment in a preclinical head and neck model, allowing for better understanding of liquid biopsy applications in both clinical practice and research development.

Recent advances in blood-based and artificial intelligence-enhanced approaches for gastrointestinal cancer diagnosis

Gastrointestinal (GI) cancers are among the most common cancer types and leading causes of cancer-related deaths worldwide. There is a tremendous clinical need for effective early diagnosis for better healthcare of GI cancer patients. In this article, we provide a short overview of the recent advances in GI cancer diagnosis. In the first part, we discuss the applications of blood-based biomarkers, such as plasma circulating cell-free DNA, circulating tumor cells, extracellular vesicles, and circulating cell-free RNA, for cancer liquid biopsies. In the second part, we review the current trends of artificial intelligence (AI) for pathology image and tissue biopsy analysis for GI cancer, as well as deep learning-based approaches for purity assessment of tissue biopsies. We further provide our opinions on the future directions in blood-based and AI-enhanced approaches for GI cancer diagnosis, and we think that these fields will have more intensive integrations with clinical needs in the near future.

Genomic analysis of circulating tumor cells in adenosquamous carcinoma of the prostate: a case report

Background

Adenosquamous carcinoma of the prostate (ASCP) is an extremely rare and aggressive prostate cancer variant, whose genomic characteristics have not been elucidated. Although liquid biopsy of circulating tumor cells (CTCs) is an emerging topic in oncology, no study has assessed CTCs in patients with ASCP.

Case presentation.

A 76-year-old man presented with discomfort in his urethra. His prostate-specific antigen (PSA) level was 13.37 ng/mL. A computed tomography (CT) scan indicated a prostate mass with multiple lymph node and lung metastases. The patient underwent transurethral resection of the prostate and prostatic needle biopsy; both specimens demonstrated Gleason grade group 5 acinar adenocarcinoma of the prostate. Bone scintigraphy indicated bone metastasis in the ischium. Combined androgen blockade was implemented, and his serum PSA level rapidly decreased to 0.01 ng/mL. However, a CT scan 6 months after the initial diagnosis revealed worsening of the disease. The patient therefore underwent repeated prostatic needle biopsy; its specimen demonstrated prostatic adenocarcinoma together with squamous carcinoma components. As immunohistochemical analyses showed the tumor cells to be negative for CD56, chromogranin A, synaptophysin, and PSA, the definitive diagnosis was ASCP. Although the patient underwent chemotherapy (docetaxel and cabazitaxel), he died of the disease 3 months after the diagnosis of ASCP, or 13 months after the initial diagnosis of prostatic adenocarcinoma. His PSA values remained ≤ 0.2 ng/mL. CTCs from the patient’s blood (collected before starting docetaxel) were analyzed and genomically assessed. It showed 5 cytokeratin (CK)⁺ CTCs, 14 CK⁻ CTCs, and 8 CTC clusters, per 10 mL. Next-generation sequencing identified a total of 14 mutations in 8 oncogenes or tumor suppressor genes: PIK3CB, APC, CDKN2A, PTEN, BRCA2, RB1, TP53, and CDK12. Of 14 mutations, 9 (64%) were detected on CK⁻ CTCs and 5 (36%) were detected on CK⁺ CTCs.

Conclusions

This is the first report of CTC analysis and genomic assessment in ASCP. Although the prognosis of ASCP is dismal due to lack of effective treatment, genomic analysis of CTCs might lead to effective treatment options and improved survival.