Circulating tumour cell increase as a biomarker of disease progression in metastatic castration-resistant prostate cancer patients with low baseline CTC counts

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.

Identification of functional and diverse circulating cancer-associated fibroblasts in metastatic castration-naïve prostate cancer patients

In prostate cancer (PCa), cancer-associated fibroblasts (CAFs) promote tumor progression, drug resistance, and metastasis. Although circulating tumor cells are studied as prognostic and diagnostic markers, little is known about other circulating cells and their association with PCa metastasis. Here, we explored the presence of circulating CAFs (cCAFs) in metastatic castration-naïve prostate cancer (mCNPC) patients. cCAFs were stained with fibroblast activation protein (FAP), epithelial cell adhesion molecule (EpCAM), and receptor-type tyrosine-protein phosphatase C (CD45), then FAP+EpCAM- cCAFs were enumerated and sorted using fluorescence-activated cell sorting. FAP+EpCAM- cCAFs ranged from 60 to 776 (389 mean ± 229 SD) per 2 × 108 mononuclear cells, whereas, in healthy donors, FAP+ EpCAM- cCAFs ranged from 0 to 71 (28 mean ± 22 SD). The mCNPC-derived cCAFs showed positivity for vimentin and intracellular collagen-I. They were viable and functional after sorting, as confirmed by single-cell collagen-I secretion after 48 h of culturing. Two cCAF subpopulations, FAP+CD45- and FAP+CD45+, were identified, both expressing collagen-I and vimentin, but with distinctly different morphologies. Collectively, this study demonstrates the presence of functional and viable circulating CAFs in mCNPC patients, suggesting the role of these cells in prostate cancer.

The detection of circulating tumor cells indicates poor therapeutic efficacy and prognosis in patients with nonsmall cell lung cancer: A systematic review and meta-analysis

OBJECTIVE

The efficacy and prognostic value of circulating tumor cells (CTCs) in nonsmall cell lung cancer (NSCLC) are controversial based on the existing research. This systematic review and meta-analysis evaluated the significance of CTCs in NSCLC therapy monitoring and prognosis prediction, supporting their potential as clinical biomarkers.

METHODS

We conducted a comprehensive search of PubMed, Embase, Web of Science, The Cochrane Library, WanFang Data, CNKI, and VIP through September 20, 2023. Inclusion criteria were cohort studies involving NSCLC patients, focusing on peripheral blood CTCs, and assessing outcomes such as pre- and posttreatment CTC rates or levels, progression-free survival (PFS), and overall survival (OS). Two reviewers independently extracted the data and assessed risk of bias using the Newcastle-Ottawa Scale. We utilized Review Manager 5.4.1 for meta-analysis, calculating pooled odds ratios (ORs) for dichotomous outcomes, mean differences for continuous variables and hazard ratios (HRs) for survival data, applying fixed- or random-effects models based on heterogeneity assessed by the I2 statistic. This study was registered in PROSPERO (No. CRD42023450035).

RESULTS

Twenty-two eligible studies with a total of 1674 NSCLC patients were included. Meta-analysis results showed that the CTCs-positive rate (OR = 0.59, 95% CI 0.45 to 0.77, p = 0.0001) and CTCs count (mean difference = -3.10, 95% CI -5.52 to -0.69, p = 0.01) were significantly decreased after antitumor treatment. Compared with the CTCs nonreduced group, the CTC-reduced group showed better PFS (HR = 1.71, 95% CI 1.35 to 2.17, p < 0.00001) and OS (HR = 1.50, 95% CI 1.21 to 1.86, p = 0.0003) after treatment. PFS and OS in CTC-positive groups were lower than those in the CTCs-negative group pretreatment (HR = 2.49, 95% CI 1.78 to 3.47, p < 0.00001; HR = 1.80, 95% CI 1.29 to 2.52, p = 0.0006) and posttreatment (HR = 3.36, 95% CI 2.12 to 5.33, p < 0.00001; HR = 3.31, 95% CI 1.75 to 6.27, p = 0.0002).

CONCLUSIONS

CTCs can be used as a biomarker to monitor NSCLC efficacy, predict prognosis and guide follow-up treatment.

The Detection and Negative Reversion of Circulating Tumor Cells as Prognostic Biomarkers for Metastatic Castration-Resistant Prostate Cancer with Bone Metastases Treated by Enzalutamide

Enzalutamide is a second-generation androgen receptor inhibitor that increases overall survival (OS) rates in patients with metastatic castration-resistant prostate cancer (mCRPC). This study evaluates the efficacy of circulating tumor cell (CTC) status as a prognostic biomarker following enzalutamide administration. A retrospective subgroup analysis and prognostic survey were conducted on 43 patients with mCRPC and bone metastases treated in Juntendo University-affiliated hospitals from 2015 to 2022. Patients were treated with 160 mg enzalutamide daily. CTC analyses on blood samples were performed regularly before and every three months after treatment. The relationship between the patients' clinical factors and the OS rate was analyzed using the log-rank test; the median OS was 37 months. Patients with no detected CTCs at baseline showed significantly longer OS than those with detectable CTCs at baseline. Furthermore, patients demonstrating negative reversion of CTCs during enzalutamide treatment had significantly longer OS than patients with CTC-positivity. Two biomarkers-higher hemoglobin at baseline and achieving negative reversion of CTCs-were significantly associated with prolonged OS. This study suggests that patients achieving CTC-negative reversion during treatment for mCRPC with bone metastases exhibit improved long-term OS. Chronological measurement of CTC status might be clinically useful in the treatment of mCRPC.

Circulating Tumor Cells: From Basic to Translational Research

BACKGROUND

Metastasis is the leading cause of cancer-related deaths. Most studies have focused on the primary tumor or on overt metastatic lesions, leaving a significant knowledge gap concerning blood-borne cancer cell dissemination, a major step in the metastatic cascade. Circulating tumor cells (CTCs) in the blood of patients with solid cancer can now be enumerated and investigated at the molecular level, giving unexpected information on the biology of the metastatic cascade.

CONTENT

Here, we reviewed recent advances in basic and translational/clinical research on CTCs as key elements in the metastatic cascade.

SUMMARY

Findings from translational studies on CTCs have elucidated the complexity of the metastatic process. Fully understanding this process will open new potential avenues for cancer therapeutic and diagnostic strategies to propose precision medicine to all cancer patients.

Comparative efficacy of olaparib in combination with or without novel antiandrogens for treating metastatic castration-resistant prostate cancer

Background

Studies using novel antiandrogens (NAA) in patients with metastatic castration-resistant prostate cancer (mCRPC) have shown overall survival benefit. As patients develop resistance to NAA therapy, the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib in combination with NAA may become a promising therapy. However the overall benefit of olaparib monotherapy or combination therapy still needs to be evaluated. Therefore, we performed a network meta-analysis to assess the efficacy and toxicity between olaparib, olaparib combined with abiraterone and NAA.

Methods

We searched PubMed, EMBASE, the Cochrane Library and American Society of Clinical Oncology (ASCO) University Meeting abstracts for randomized controlled trials reporting olaparib and NAA from 2010 up to March, 2023. Network meta-analysis using Stata 16.0 and R 4.4.2, hazard ratios (HR) with 95% confidence intervals (CI) were used to assess the results.

Results

Four trials reported olaparib, olaparib plus abiraterone and apalutamide plus abiraterone. radiographic progression-free survival (rPFS) was significantly lower in patients on apalutamide plus abiraterone compared to olaparib (HR, 1.43; 95% CI, 1.06-1.93). rPFS was similar for olaparib plus abiraterone and olaparib (HR, 1.35; 95% CI, 0.99-1.84); likewise, olaparib plus abiraterone and apalutamide plus abiraterone were similar (HR, 1.06; 95% CI, 0.83-1.35). In addition, there was no significant difference between the three interventions for OS. But olaparib has the highest probability of being a preferred treatment for improving rPFS and OS.

Conclusion

rPFS was in favor of olaparib compared with apalutamide plus abiraterone. But there were no difference between olaparib plus abiraterone and either olaparib or apalutamide plus abiraterone. Apalutamide plus abiraterone might be the most preferred intervention in cases where AEs are involved.

Systematic review registration

https://inplasy.com, identifier INPLASY2023100072.

OCT4‑positive circulating tumor cells may predict a poor prognosis in patients with metastatic castration‑resistant prostate cancer treated with abiraterone plus prednisone therapy

Octamer-binding transcription factor 4 (OCT4) and circulating tumor cells (CTCs) are key factors associated with tumor metastasis and drug resistance in cancer. The present prospective study aimed to investigate the prevalence of OCT4-positive (OCT4+) CTCs and the potential association with the clinical features and survival of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone + prednisone. In total, 70 patients with mCRPC treated with abiraterone + prednisone were enrolled in the present study and peripheral blood samples were collected prior to treatment initiation to determine CTC count via a Canpatrol system. RNA in situ hybridization was performed for OCT4+ CTC quantification. Lactate dehydrogenase (LDH) was detected by automatic biochemical analyzer (AU54000, OLYMPUS). Results demonstrated that 34 (48.6%), 21 (30.0%) and 15 (21.4%) patients harbored OCT4+ (CTC+/OCT4+) or OCT4-negative CTCs (CTC+/OCT4-) or were CTC-negative (CTC-), respectively. Notably, CTC+/OCT4+ occurrence was associated with visceral metastasis and high levels of LDH. In addition, radiographic progression-free survival [rPFS; median, 15.0, 95% confidence interval (CI), 9.6-20.4 vs. not reached vs. median, 29.5, 95% CI, 18.6-40.4 months; P=0.001] and overall survival (OS) were significantly decreased (median, 27.3, 95% CI, 20.1-34.5 vs. not reached vs. not reached; P=0.016) in CTC+/OCT4+ compared with CTC+/OCT4- and CTC- patients. Subsequently, the adjustment was performed by multivariate Cox regression models, which revealed that CTC+/OCT4+ (vs. CTC+/OCT4- or CTC-) was independently associated with decreased rPFS [hazard ratio (HR), 3.833; P<0.001] and OS (HR, 3.938; P=0.008). In conclusion, OCT4+ CTCs were highly prevalent in patients with mCRPC and associated with visceral metastasis and increased levels of LDH. Thus, the presence of OCT4+ CTCs may serve as an independent prognostic factor for patients with mCRPC treated with abiraterone + prednisone.

Recent Advances in Blood-Based Liquid Biopsy Approaches in Prostate Cancer

ABSTRACT

The advent of high-throughput technologies has enabled the analysis of minute amounts of tumor-derived material purified from body fluids, termed "liquid biopsies." Prostate cancer (PCa) management, like in many other cancer types, has benefited from liquid biopsies at several stages of the disease. Although initially describing circulating tumor cells in blood, the term "liquid biopsy" has come to more prominently include cell-free, circulating tumor DNA, as well as RNA, proteins, and other molecules. They provide tumor molecular information representing the entire, often-heterogeneous disease, relatively noninvasively and longitudinally. Blood has been the main liquid biopsy specimen in PCa, and urine has also proven beneficial. Technological advances have allowed clinical implementation of some liquid biopsies in PCa, in disease monitoring and precision oncology. This narrative review introduces the main types of blood-based PCa liquid biopsies focusing on advances in the past 5 years. Clinical adoption of liquid biopsies to detect and monitor the evolving PCa tumor biology promises to deepen our understanding of the disease and improve patient outcomes.

Integrated "lab-on-a-chip" microfluidic systems for isolation, enrichment, and analysis of cancer biomarkers

The liquid biopsy has garnered considerable attention as a complementary clinical tool for the early detection, molecular characterization and monitoring of cancer over the past decade. In contrast to traditional solid biopsy techniques, liquid biopsy offers a less invasive and safer alternative for routine cancer screening. Recent advances in microfluidic technologies have enabled handling of liquid biopsy-derived biomarkers with high sensitivity, throughput, and convenience. The integration of these multi-functional microfluidic technologies into a 'lab-on-a-chip' offers a powerful solution for processing and analyzing samples on a single platform, thereby reducing the complexity, bio-analyte loss and cross-contamination associated with multiple handling and transfer steps in more conventional benchtop workflows. This review critically addresses recent developments in integrated microfluidic technologies for cancer detection, highlighting isolation, enrichment, and analysis strategies for three important sub-types of cancer biomarkers: circulating tumor cells, circulating tumor DNA and exosomes. We first discuss the unique characteristics and advantages of the various lab-on-a-chip technologies developed to operate on each biomarker subtype. This is then followed by a discussion on the challenges and opportunities in the field of integrated systems for cancer detection. Ultimately, integrated microfluidic platforms form the core of a new class of point-of-care diagnostic tools by virtue of their ease-of-operation, portability and high sensitivity. Widespread availability of such tools could potentially result in more frequent and convenient screening for early signs of cancer at clinical labs or primary care offices.

Detection and Molecular Characterization of Circulating Tumour Cells: Challenges for the Clinical Setting

Over the last decade, liquid biopsy has gained much attention as a powerful tool in personalized medicine since it enables monitoring cancer evolution and follow-up of cancer patients in real time. Through minimally invasive procedures, liquid biopsy provides important information through the analysis of circulating tumour cells (CTCs) and circulating tumour-derived material, such as circulating tumour DNA (ctDNA), circulating miRNAs (cfmiRNAs) and extracellular vehicles (EVs). CTC analysis has already had an important impact on the prognosis, detection of minimal residual disease (MRD), treatment selection and monitoring of cancer patients. Numerous clinical trials nowadays include a liquid biopsy arm. CTC analysis is now an exponentially expanding field in almost all types of solid cancers. Functional studies, mainly based on CTC-derived cell-lines and CTC-derived explants (CDx), provide important insights into the metastatic process. The purpose of this review is to summarize the latest findings on the clinical significance of CTCs for the management of cancer patients, covering the last four years. This review focuses on providing a comprehensive overview of CTC analysis in breast, prostate and non-small-cell lung cancer. The unique potential of CTC single-cell analysis for understanding metastasis biology, and the importance of quality control and standardization of methodologies used in this field, is also discussed.

Co-expression and clinical utility of AR-FL and AR splice variants AR-V3, AR-V7 and AR-V9 in prostate cancer

BACKGROUND

Androgen receptor (AR) splice variants (AR-Vs) have been discussed as a biomarker in prostate cancer (PC). However, some reports question the predictive property of AR-Vs. From a mechanistic perspective, the connection between AR full length (AR-FL) and AR-Vs is not fully understood. Here, we aimed to investigate the dependence of AR-FL and AR-V expression levels on AR gene activity. Additionally, we intended to comprehensively analyze presence of AR-FL and three clinically relevant AR-Vs (AR-V3, AR-V7 and AR-V9) in different stages of disease, especially with respect to clinical utility in PC patients undergoing AR targeted agent (ARTA) treatment.

METHODS

AR-FL and AR-V levels were analyzed in PC and non-PC cell lines upon artificial increase of AR pre-mRNA using either drug treatment or AR gene activation. Furthermore, expression of AR-FL and AR-Vs was determined in PC specimen at distinct stages of disease (primary (n = 10) and metastatic tissues (n = 20), liquid biopsy samples (n = 422), mCRPC liquid biopsy samples of n = 96 patients starting novel treatment). Finally, baseline AR-FL and AR-V status was correlated with clinical outcome in a defined cohort of n = 65 mCRPC patients undergoing ARTA treatment.

RESULTS

We revealed rising levels of AR-FL accompanied with appearance and increase of AR-Vs in dependence of elevated AR pre-mRNA levels. We also noticed increase in AR-FL and AR-V levels throughout disease progression. AR-V expression was always associated with high AR-FL levels without any sample being solely AR-V positive. In patients undergoing ARTA treatment, AR-FL did show prognostic, yet not predictive validity. Additionally, we observed a substantial clinical response to ARTA treatment even in AR-V positive patients. Accordingly, multivariate analysis did not demonstrate independent significance of AR-Vs in neither predictive nor prognostic clinical utility.

CONCLUSION

We demonstrate a correlation between AR-FL and AR-V expression during PC progression; with AR-V expression being a side-effect of elevated AR pre-mRNA levels. Clinically, AR-V positivity relies on high levels of AR-FL, making cells still vulnerable to ARTA treatment, as demonstrated by AR-FL and AR-V positive patients responding to ARTA treatment. Thus, AR-FL and AR-V might be considered as a prognostic, yet not predictive biomarker in mCRPC patients.

Dynamics of CXCR4 positive circulating tumor cells in prostate cancer patients during radiotherapy

Ablative radiotherapy is a highly efficient treatment modality for patients with metastatic prostate cancer (PCa). However, a subset of patients does not respond. Currently, this subgroup with bad prognosis cannot be identified before disease progression. We hypothesize that markers indicative of radioresistance, stemness and/or bone tropism may have a prognostic potential to identify patients profiting from metastases-directed radiotherapy. Therefore, circulating tumor cells (CTCs) were analyzed in patients with metastatic PCa (n = 24) during radiotherapy with CellSearch, multicolor flow cytometry and imaging cytometry. Analysis of copy-number alteration indicates a polyclonal CTC population that changes after radiotherapy. CTCs were found in 8 out of 24 patients (33.3%) and were associated with a shorter time to biochemical progression after radiotherapy. Whereas the total CTC count dropped after radiotherapy, a chemokine receptor CXCR4-expressing subpopulation representing 28.6% of the total CTC population remained stable up to 3 months. At once, we observed higher chemokine CCL2 plasma concentrations and proinflammatory monocytes. Additional functional analyses demonstrated key roles of CXCR4 and CCL2 for cellular radiosensitivity, tumorigenicity and stem-like potential in vitro and in vivo. Moreover, a high CXCR4 and CCL2 expression was found in bone metastasis biopsies of PCa patients. In summary, panCK⁺ CXCR4⁺ CTCs may have a prognostic potential in patients with metastatic PCa treated with metastasis-directed radiotherapy.

MyCTC chip: microfluidic-based drug screen with patient-derived tumour cells from liquid biopsies

Cancer patients with advanced disease are characterized by intrinsic challenges in predicting drug response patterns, often leading to ineffective treatment. Current clinical practice for treatment decision-making is commonly based on primary or secondary tumour biopsies, yet when disease progression accelerates, tissue biopsies are not performed on a regular basis. It is in this context that liquid biopsies may offer a unique window to uncover key vulnerabilities, providing valuable information about previously underappreciated treatment opportunities. Here, we present MyCTC chip, a novel microfluidic device enabling the isolation, culture and drug susceptibility testing of cancer cells derived from liquid biopsies. Cancer cell capture is achieved through a label-free, antigen-agnostic enrichment method, and it is followed by cultivation in dedicated conditions, allowing on-chip expansion of captured cells. Upon growth, cancer cells are then transferred to drug screen chambers located within the same device, where multiple compounds can be tested simultaneously. We demonstrate MyCTC chip performance by means of spike-in experiments with patient-derived breast circulating tumour cells, enabling >95% capture rates, as well as prospective processing of blood from breast cancer patients and ascites fluid from patients with ovarian, tubal and endometrial cancer, where sensitivity to specific chemotherapeutic agents was identified. Together, we provide evidence that MyCTC chip may be used to identify personalized drug response patterns in patients with advanced metastatic disease and with limited treatment opportunities.

New perspectives in liquid biopsy for glioma patients

PURPOSE OF REVIEW

Gliomas are the most common primary tumors of the central nervous system. They are characterized by a disappointing prognosis and ineffective therapy that has shown no substantial improvements in the past 20 years. The lack of progress in treating gliomas is linked with the inadequacy of suitable tumor samples to plan translational studies and support laboratory developments. To overcome the use of tumor tissue, this commentary review aims to highlight the potential for the clinical application of liquid biopsy (intended as the study of circulating biomarkers in the blood), focusing on circulating tumor cells, circulating DNA and circulating noncoding RNA.

RECENT FINDINGS

Thanks to the increasing sensitivity of sequencing techniques, it is now possible to analyze circulating nucleic acids and tumor cells (liquid biopsy).

SUMMARY

Although studies on the use of liquid biopsy are still at an early stage, the potential clinical applications of liquid biopsy in the study of primary brain cancer are many and have the potential to revolutionize the approach to neuro-oncology, and importantly, they offer the possibility of gathering information on the disease at any time during its history.

Drug susceptibility testing of circulating lung cancer cells for personalized treatment

The presence of Circulating tumor cells (CTCs) has been proven to be correlated with disease progression and the patient's response to treatment. However, the culture of CTCs for clinical utility is still a big challenge. We have developed a short-term method that enables CTCs culture and provides an opportunity to monitor drug susceptibility testing in individual patients. In a proof-of-concept study, we established a unique method using Matrigel® coated in 96 well plate to enable cancer cell clusters to attach and proliferate. The culture method using Matrigel® provides in vitro conditions and improves the attachment and differentiation of anchorage-dependent epithelial cells proliferation and mimics the tumor microenvironment. We further treated the cells attached to Matrigel® with the same drug regimen as the patient has undergone. Around 30.7% of the CTCs were viable after the drug treatment. We also correlated the decrease in cell viability after drug treatment with the reduction in the pleural effusion of the patient as seen by the images obtained from CT scans pre-and post-treatment. Moreover, as per the RECIST criterion, the patient had exhibited a positive response to the treatment. The short-term culturing of CTC along with the drug susceptibility testing offers a novel method to predict patient response to the treatment and could be utilized for screening suitable drug combinations for personalized treatment.

Integration of Liquid Biopsies in Clinical Management of Metastatic Prostate Cancer

PURPOSE OF REVIEW

The field of liquid biopsies is constantly evolving through novel technologies. This review outlines current data on liquid biopsies and application to clinical management of metastatic prostate cancer.

RECENT FINDINGS

To date, there are three platforms with FDA approval for use in the setting of metastatic prostate cancer and others which have been clinically validated. There is substantial evidence supporting the use of circulating tumor cell (CTC) enumeration to guide prognosis in metastatic castration-resistant prostate cancer (mCRPC). Additional evidence supports targeted sequencing of CTC and cell-free DNA (cfDNA) to guide androgren-directed therapy, identify candidates for treatment with PARP inhibitors, and monitor development of resistance. As a real-time and minimally invasive approach, utilization of liquid biopsies has the potential to drastically impact the treatment of metastatic prostate cancer and improve overall survival. With further clinical validation, additional liquid biopsy is likely to enter standard clinical practice.

Characterizing Circulating Tumor Cells and Tumor-Derived Extracellular Vesicles in Metastatic Castration-Naive and Castration-Resistant Prostate Cancer Patients

Simple Summary

The composition of circulating tumor cells (CTCs) and tumor-derived extracellular vesicles (tdEVs) in the blood of 104 patients with metastatic castration-naive prostate cancer and 66 patients with metastatic castration-resistant prostate cancer was compared to explore the potential differences between these biomarkers in the two disease stages.

Abstract

Circulating tumor cell (CTC)- and/or tumor-derived extracellular vesicle (tdEV) loads in the blood of metastatic castration-resistant prostate cancer (CRPC) patients are associated with worse overall survival and can be used as predictive markers of treatment response. In this study, we investigated the quantity/quality of CTCs and tdEVs in metastatic castration-naive prostate cancer (CNPC) and CRPC patients, and whether androgen deprivation therapy (ADT) affects CTCs and tdEVs. We included 104 CNPC patients before ADT initiation and 66 CRPC patients. Blood samples from 31/104 CNPC patients were obtained 6 months after ADT. CTCs and tdEVs were identified using ACCEPT software. Based on the morphology, CTCs of metastatic CNPC and CRPC patients were subdivided by manual reviewing into six subclasses. The numbers of CTCs and tdEVs were correlated in both CNPC and CRPC patients, and both CTCs (p = 0.013) and tdEVs (p = 0.005) were significantly lower in CNPC compared to CRPC patients. Qualitative differences in CTCs were observed: CTC clusters (p = 0.006) and heterogeneously CK expressing CTCs (p = 0.041) were significantly lower in CNPC patients. CTC/tdEV numbers declined 6 months after ADT. Our study showed that next to CTC-load, qualitative CTC analysis and tdEV-load may be useful in CNPC patients.

A Systematic Review of Circulating Tumor Cells Clinical Application in Prostate Cancer Diagnosis

Simple Summary

Cell-dependent and cell-independent information drawn from the blood stream were merged into the attractive term “liquid biopsy” and tentatively applied to most segments of cancer management: detection, risk-stratification, personalization of care and follow-up. However, the robust science behind liquid biopsies has not been widely used, thereby remaining a latent and possibly undervalued instrument. Here, we conducted a systematic review of CTCs in prostate cancer management to summarize their use in clinical practice.

Abstract

The purpose of the review is to summarize the recent data on circulating tumor cells (CTC) use in clinical practice. We performed a systematic literature search using two databases (Medline and Scopus) over the past five years and the following terms: (CTC OR “circulating tumor cells” OR “liquid biopsy”) AND prostate. The primary outcome was CTC predictive value for prostate cancer (PC) progression and survival. The secondary outcomes were the CTC predictive value for therapy response and the results of CTC detection depending on the assessment method. In metastatic PC, the CTC count showed itself to be a prognostic marker in terms of clinically important features, namely survival rates and response to treatment. CTC concentration was significantly associated with the overall survival and progression-free survival rates. A strong association between the overall survival or progression-free survival rate and CTC concentration could be observed. Variant-7 androgen receptors-positive (AR-V7-positive) patients showed a poor response to androgen receptor signaling (ARS) inhibitors, but this did not compromise their response to taxanes. In localized PC, only positive Cluster of Differentiantion 82 protein (CD82+) correlated with a higher survival rate. CTC count and AR-V7 expression showed itself to be a valuable biomarker for survival in metastatic PC and response to ARS-inhibitors. CTC diagnostic performance for localized PC or for screening and early detection is not high enough to show additional value over the other biomarkers.

Comparison of circulating tumor cells and AR-V7 as clinical biomarker in metastatic castration-resistant prostate cancer patients

Biomarker in metastatic castration resistant prostate cancer (mCRPC) treatment are rare. We aimed to compare the clinical value of circulating tumor cells (CTCs) and androgen receptor splice variant 7 (AR-V7) as biomarker in mCRPC patients undergoing androgen receptor-targeted agent (ARTA) treatment. Overall cohort (65 patients) was stratified regarding either CTC or AR-V7 status followed by further sub-stratification of the respective other marker. Subsequently, prostate specific antigen (PSA) response, progression free survival (PFS) and overall survival (OS)) of subgroups was compared. CTCs and AR-V7 were detected in 54 (83%) and 33 (61%) patients, respectively. All AR-V7 + were CTC +. We detected PSA response in all subgroups. For PFS and OS, biomarker stratification revealed differences between all subgroups. Interestingly, no significant differences of AR-V7 transcript copy numbers were detected between responding and non-responding patients. Additionally, multivariable analysis revealed no independent prognostic value of AR-V7 positivity. Both biomarkers show clinical value in prognosticating clinical outcome. Nonetheless, AR-V7 stratification underestimates the heterogenous subgroup of CTC - and CTC + patient, the latter requiring more intense clinical surveillance. Additionally, AR-V7 level does not correlate with clinical response. Thus, the value of AR-V7 as a clinical biomarker must be considered skeptically.

Clinical Applications of Liquid Biopsy in Prostate Cancer: From Screening to Predictive Biomarker

Prostate cancer (PC) remains the most common malignancy and the second most common cause of cancer death in men. As a result of highly variable biological behavior and development of resistance to available agents under therapeutic pressure, optimal management is often unclear. Traditional surgical biopsies, even when augmented by genomic studies, may fail to provide adequate guidance for clinical decisions as these can only provide a snapshot of a dynamic process. Additionally, surgical biopsies are cumbersome to perform repeatedly and often involve risk. Liquid biopsies (LB) are defined as the analysis of either corpuscular (circulating tumor cells, extracellular vesicles) or molecular (circulating DNA or RNA) tumor-derived material. LB could more precisely identify clinically relevant alterations that characterize the metastatic potential of tumors, predict response to specific treatments or actively monitor for the emergence of resistance. These tests can potentially be repeated as often as deemed necessary and can detect real-time response to treatment with minimal inconvenience to the patient. In the current review, we consider common clinical scenarios to describe available LB assays in PC as a platform to explore existing evidence for their use in guiding decision making and to discuss current limitations to their adoption in the clinic.

Liquid Biopsy and Dielectrophoretic Analysis—Complementary Methods in Skin Cancer Monitoring

The incidence and prevalence of skin cancers is currently increasing worldwide, with early detection, adequate treatment, and prevention of recurrences being topics of great interest for researchers nowadays. Although tumor biopsy remains the gold standard of diagnosis, this technique cannot be performed in a significant proportion of cases, so that the use of alternative methods with high sensitivity and specificity is becoming increasingly desirable. In this context, liquid biopsy appears to be a feasible solution for the study of cellular and molecular markers relevant to different types of skin cancers. Circulating tumor cells are just one of the components of interest obtained from performing liquid biopsy, and their study by complementary methods, such as dielectrophoresis, could bring additional benefits in terms of characterizing skin tumors and subsequently applying personalized therapy. One purpose of this review is to demonstrate the utility of liquid biopsy primarily in monitoring the most common types of skin tumors: basal cell carcinoma, squamous cell carcinoma, and malign melanoma. In addition, the originality of the article is based on the detailed presentation of the dielectrophoretic analysis method of the most important elements obtained from liquid biopsy, with direct impact on the clinical and therapeutic approach of skin tumors.

Non-Invasive Profiling of Advanced Prostate Cancer via Multi-Parametric Liquid Biopsy and Radiomic Analysis

Integrating liquid biopsies of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) with other minimally invasive measures may yield more comprehensive disease profiles. We evaluated the feasibility of concurrent cellular and molecular analysis of CTCs and cfDNA combined with radiomic analysis of CT scans from patients with metastatic castration-resistant PC (mCRPC). CTCs from 22 patients were enumerated, stained for PC-relevant markers, and clustered based on morphometric and immunofluorescent features using machine learning. DNA from single CTCs, matched cfDNA, and buffy coats was sequenced using a targeted amplicon cancer hotspot panel. Radiomic analysis was performed on bone metastases identified on CT scans from the same patients. CTCs were detected in 77% of patients and clustered reproducibly. cfDNA sequencing had high sensitivity (98.8%) for germline variants compared to WBC. Shared and unique somatic variants in PC-related genes were detected in cfDNA in 45% of patients (MAF > 0.1%) and in CTCs in 92% of patients (MAF > 10%). Radiomic analysis identified a signature that strongly correlated with CTC count and plasma cfDNA level. Integration of cellular, molecular, and radiomic data in a multi-parametric approach is feasible, yielding complementary profiles that may enable more comprehensive non-invasive disease modeling and prediction.

Evaporation-Induced rGO Coatings for Highly Sensitive and Non-Invasive Diagnosis of Prostate Cancer in the PSA Gray Zone

The prostate-specific antigen (PSA) has been widely used for the early diagnosis of prostate cancer during routine check-ups. However, the low sensitivity of regular PSA tests in the PSA gray zone often means that patients are required to undergo further invasive needle biopsy for the diagnosis of prostate cancer, which may lead to potential overdiagnosis and overtreatment. In this study, a circulating tumor cell (CTC)-chip based on an evaporation-induced reduced graphene oxide (rGO) coating is presented, which enables a highly specific and non-invasive diagnosis of prostate cancer in the PSA gray zone. During the evaporation process of the rGO dispersion, the Marangoni effect induces the self-assembly of a hierarchical micro/nanowrinkled rGO coating, which can capture CTCs after subsequent surface modification of capture agents. Compared to the low diagnostic sensitivity (58.3%) of regular PSA tests, a combination of CTC detection and PSA-based hematological tests via machine-learning analysis can greatly upgrade the diagnostic sensitivity of this disease to 91.7% in clinical trial. Therefore, this study provides a non-invasive alternative with high sensitivity for the diagnosis of prostate cancer in the PSA gray zone.

The role of liquid biopsies in prostate cancer management

Liquid biopsy has emerged as a complement to invasive tissue biopsy to guide cancer diagnosis and treatment. The common liquid biopsy biomarkers are circulating tumor cells (CTCs), extracellular vesicles (EVs), and circulating tumor DNA (ctDNA). Each biomarker provides specific information based on its intrinsic characteristics. Prostate cancer is the second most common cancer in males worldwide. In men with low-grade localized prostate cancer, the disease can often be managed by active surveillance. For men who require treatment, the 5-year survival rate of localized prostate cancer is the highest among all cancer types, but the metastatic disease remains incurable. Metastatic prostate cancer invariably progresses to involve multiple bone sites and develops into a castration-resistant disease that leads to cancer death. The need to appropriately diagnose and guide the serial treatment of men with prostate cancer has led to the implementation of many studies to apply liquid biopsies to prostate cancer management. This review describes recent advancements in isolation and detection technology and the strength and weaknesses of the three circulating biomarkers. The clinical studies based on liquid biopsy results are summarized to depict the future perspective in the role of liquid biopsy on prostate cancer management.

Association of Circulating Tumor Cells with Inflammatory and Biomarkers in the Blood of Patients with Metastatic Castration-Resistant Prostate Cancer

The identification of specific biomarkers that recognize the functional drivers of heterogeneity in prostate cancer (PCa) and personalized treatment remain challenging in systemic medicine. Liquid biopsy allows for the detection and analysis of personalized predictive biomarkers in single blood samples and specifies the current stage of cancer. The aim of our preliminary study was to investigate the association between an elevated circulating tumor cell (CTC) count and the levels of inflammatory factors (IL-6 and IL-8) and biomarkers (DKK-1, PSA, sHER2, and CD44) in patients with metastasized castration-resistant PCa (mCPRC) under chemotherapy and those with localized PCa. Such an association could be used as a component of cancer progression monitoring. We compared the sensitivity and specificity of two CTC isolation platforms. Twenty-eight patients (12 mCRPC and 16 localized PCa patients) were enrolled. Over the study period, the CTC detection rates were 84% with CellCollector^® and 73.5% with CellSearch^® System in mCPRC patients. The CTC counts determined by the CellSearch^® System (CTC_CS) were correlated significantly with the DKK-1, sHER-2, and PSA concentrations in mCRPC patients. The CTC counts captured by CellCollector^® demonstrated no significant association with the concentrations of the tested blood-based biomarkers. The CTC_CS count (AUC = 0.9 (95% CI: 0.72–1.0)) and the PSA level (AUC = 0.95 (95% CI: 0.83–1.0)) presented approximately the same sensitivity and specificity for the overall survival of mCRPC patients. For better personalized characterization, further research on CTC phenotyping and their interactions with tumor-associated blood-released factors is needed.

Value of Early Circulating Tumor Cells Dynamics to Estimate Docetaxel Benefit in Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients

Simple Summary

The prognostic role of CTC enumeration in mCRPC patients has been established in several studies, demonstrating a higher prognostic performance than post-treatment changes in PSA levels in patients treated with AR signaling inhibitors, but not taxanes. We carried out a pooled analysis of two prospective studies in mCRPC patients treated with docetaxel. The results of this study showed a greater ability of early changes in circulating tumor cells (CTCs) compared to PSA response endpoints to predict overall survival in metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel. These results encourage the clinical usefulness of CTC enumeration to determine the outcome of mCRPC patients.

Abstract

Circulating tumor cell (CTC) enumeration and changes following treatment have been demonstrated to be superior to PSA response in determining mCRPC outcome in patients receiving AR signaling inhibitors but not taxanes. We carried out a pooled analysis of two prospective studies in mCRPC patients treated with docetaxel. CTCs were measured at baseline and 3–6 weeks post treatment initiation. Cox regression models were constructed to compare 6-month radiographical progression-free survival (rPFS), CTCs and PSA changes predicting outcome. Among the subjects, 80 and 52 patients had evaluable baseline and post-treatment CTC counts, respectively. A significant association of higher baseline CTC count with worse overall survival (OS), PFS and time to PSA progression (TTPP) was observed. While CTC response at 3–6 weeks (CTC conversion (from ≥5 to <5 CTCs), CTC30 (≥30% decline in CTC) or CTC0 (decline to 0 CTC)) and 6-month rPFS were significantly associated with OS (all p < 0.005), the association was not significant for PSA30 or PSA50 response. CTC and PSA response were discordant in over 50% of cases, with outcome driven by CTC response in these patients. The c-index values for OS were superior for early CTC changes compared to PSA response endpoints, and similar to 6-month rPFS. Early CTC declines were good predictors of improved outcomes in mCRPC patients treated with docetaxel in this small study, offering a superior and/or earlier estimation of docetaxel benefit in comparison to PSA or rPFS that merits further confirmation in larger studies.

Development and validation of circulating tumour cell enumeration (Epic Sciences) as a prognostic biomarker in men with metastatic castration-resistant prostate cancer

PURPOSE

To evaluate the prognostic significance of circulating tumour cell (CTC) number determined on the Epic Sciences platform in men with metastatic castration-resistant prostate cancer (mCRPC) treated with an androgen receptor signalling inhibitor (ARSI).

PATIENTS AND METHODS

A pre-treatment blood sample was collected from men with progressing mCRPC starting either abiraterone or enzalutamide as a first-, second- or third-line systemic therapy at Memorial Sloan Kettering Cancer Center (Discovery cohort, N = 171) or as a first- or second-line therapy as part of the multicenter PROPHECY trial (NCT02269982) (Validation cohort, N = 107). The measured CTC number was then associated with overall survival (OS) in the Discovery cohort, and progression-free survival (PFS) and OS in the Validation cohort. CTC enumeration was also performed on a concurrently obtained blood sample using the CellSearch® Circulating Tumor Cell Kit.

RESULTS

In the MSKCC Discovery cohort, CTC count was a statistically significant prognostic factor of OS as a dichotomous (<3 CTCs/mL versus ≥ 3 CTCs/mL; hazard ratio [HR] = 1.8 [95% confidence interval {CI} 1.3-3.0]) and a continuous variable when adjusting for line of therapy, presence of visceral metastases, prostate-specific antigen, lactate dehydrogenase and alkaline phosphatase. The findings were validated in an independent datas et from PROPHECY (HR [95% CI] = 1.8 [1.1-3.0] for OS and 1.7 [1.1-2.9] for PFS). A strong correlation was also observed between CTC counts determined in matched samples on the CellSearch® and Epic platforms (r = 0.84).

CONCLUSION

The findings validate the prognostic significance of pretreatment CTC number determined on the Epic Sciences platform for predicting OS in men with progressing mCRPC starting an ARSI.

BRMS1: a multifunctional signaling molecule in metastasis

Despite high mortality rates, molecular understanding of metastasis remains limited. It can be regulated by both pro- and anti-metastasis genes. The metastasis suppressor, breast cancer metastasis suppressor 1 (BRMS1), has been positively correlated with patient outcomes, but molecular functions are still being characterized. BRMS1 has been implicated in focal adhesion kinase (FAK), epidermal growth factor receptor (EGFR), and NF-κB signaling pathways. We review evidence that BRMS1 regulates these vast signaling pathways through chromatin remodeling as a member of mSin3 histone deacetylase complexes.

Quantitative and Qualitative Analysis of Blood-based Liquid Biopsies to Inform Clinical Decision-making in Prostate Cancer

CONTEXT

Genomic stratification can impact prostate cancer (PC) care through diagnostic, prognostic, and predictive biomarkers that aid in clinical decision-making. The temporal and spatial genomic heterogeneity of PC together with the challenges of acquiring metastatic tissue biopsies hinder implementation of tissue-based molecular profiling in routine clinical practice. Blood-based liquid biopsies are an attractive, minimally invasive alternative.

OBJECTIVE

To review the clinical value of blood-based liquid biopsy assays in PC and identify potential applications to accelerate the development of precision medicine.

EVIDENCE ACQUISITION

A systematic review of PubMed/MEDLINE was performed to identify relevant literature on blood-based circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vesicles (EVs) in PC.

EVIDENCE SYNTHESIS

Liquid biopsy has emerged as a practical tool to profile tumor dynamics over time, elucidating features that evolve (genome, epigenome, transcriptome, and proteome) with tumor progression. Liquid biopsy tests encompass analysis of DNA, RNA, and proteins that can be detected in CTCs, ctDNA, or EVs. Blood-based liquid biopsies have demonstrated promise in the context of localized tumors (diagnostic signatures, risk stratification, and disease monitoring) and advanced disease (response/resistance biomarkers and prognostic markers).

CONCLUSIONS

Liquid biopsies have value as a source of prognostic, predictive, and response biomarkers in PC. Most clinical applications have been developed in the advanced metastatic setting, where CTC and ctDNA yields are significantly higher. However, standardization of assays and analytical/clinical validation is necessary prior to clinical implementation.

PATIENT SUMMARY

Traces of tumors can be isolated from blood samples from patients with prostate cancer either as whole cells or as DNA fragments. These traces provide information on tumor features. These minimally invasive tests can guide diagnosis and treatment selection.

Genomic mutation profiling using liquid biopsy in Korean patients with prostate cancer: Circulating tumor DNA mutation predicts the development of castration resistance

Purpose

To investigate germline and somatic mutation profiles in Korean patients with prostate cancer using liquid biopsy and solid tissue testing and to evaluate the prognostic value of circulating tumor DNA (ctDNA) in predicting castration resistance in patients with metastatic hormone-sensitive prostate cancer (mHSPC).

Materials and Methods

Plasma samples from 56 prostate cancer patients were subjected to next-generation sequencing (NGS) to identify germline mutations and ctDNA analysis using liquid biopsy to detect somatic mutations. Additionally, paired solid cancer tissues from 18 patients were subject to NGS to detect somatic mutations. The clinical parameters and ctDNA profiles of patients with mHSPC were analyzed to evaluate the prognostic value of ctDNA mutations with respect to predicting castration resistance using Cox proportional hazards regression analysis.

Results

Germline mutations occurred in 3.6% of the patients in this cohort, with mutations identified in RAD50 (1.8%) and BRCA1 (1.8%). Somatic mutations detected by liquid biopsy and solid tissue testing were common in TP53 (12.5%), PIK3CA (3.6%), and TMPRSS2-ERG (3.6%). Of the 18 patients with paired tissue testing, two patients had at least one identical somatic mutation in both the liquid biopsy and solid tissue testing. In patients with mHSPC, the presence of ctDNA mutations could independently predict the castration resistance development (hazard ratio, 13.048; 95% confidential interval, 1.109–153.505; p=0.041).

Conclusions

Korean patients with prostate cancer showed a relatively low germline mutation rate compared to other ethnicities. The ctDNA mutations detected by liquid biopsy can predict the development of castration resistance in patients with mHSPC.

A review of current clinical biomarkers for prostate cancer: towards personalised and targeted therapy

Background:

Prostate cancer is the most commonly diagnosed cancer in men and it is responsible for about 10% of all cancer mortality in Canadian men. The current ‘gold standard’ for the diagnosis of prostate cancer is a prostate biopsy and the decision on when to biopsy a patient with non-suspicious Digital Rectal Examination (DRE) result and total prostate specific antigen (tPSA) of 4–10 ng/ml can be challenging. In order to shift the treatment paradigm of prostate cancer toward more personalised and targeted therapy, there is the need for a clear system that makes its detection binary so as to decrease the rate of inaccurate detections. Therefore in recent years, there have been several investigations into the development of various biomarkers with high sensitivity and specificity for screening, early detection and personalised patient-specific targeted medicine from diagnosis to treatment of the disease.

Materials and methods:

This paper reports on nine currently available clinical biomarkers used in screening for early detection and diagnosis, to reduce the number of unnecessary biopsies, in risk assessment of aggressive disease and in monitoring treatment response of prostate cancer.

Conclusion:

Current clinical prostate cancer biomarkers have the potential for a personalised risk assessment of aggressive disease and the risk of developing distant metastatic disease and have been proven to be useful tools to guide clinicians in personalised patient-specific targeted treatment and in the shared decision making between patients and their physicians regarding prostate biopsy and treatment. Using biomarkers to select patients with a significant probability of aggressive prostate cancer would potentially avoid premature death from the disease, while at the same time would safely preclude patients who do not require unnecessary invasive intervention.

Fundamentals of liquid biopsies in metastatic prostate cancer: from characterization to stratification

PURPOSE OF REVIEW

In this review, we provide an overview of the recent developments and prospects on the applications of blood-based liquid biopsies, including circulating tumor DNA and circulating tumor cells, in metastatic prostate cancer.

RECENT FINDINGS

Guidelines and consensus statements have been formulated to standardize preanalytical conditions that affect liquid biopsy analysis. Currently, there are four FDA approved assays for the analysis of liquid biopsies and many quantitative and qualitative assays are being developed. Comprehensive analyses of cell-free tumor DNA (ctDNA) and circulating tumor cells (CTCs) demonstrate that they adequately reflect the genomic makeup of the tumor and may thus complement or even replace tumor biopsies. The assessment of genomic aberrations in ctDNA can potentially predict therapy response and detect mechanisms of resistance. CTC count is not only a strong prognosticator in metastatic prostate cancer but can also measure therapy response.

SUMMARY

Liquid biopsies may provide a temporal snapshot of the biologic variables that affect tumor growth and progression in metastatic prostate cancer. Liquid biopsies could inform on prognostic, predictive, and response measures. However, prospective clinical trials need to be performed to provide definitive validation of the clinical value of the most advanced assays.

Position of Circulating Tumor Cells in the Clinical Routine in Prostate Cancer and Breast Cancer Patients

Simple Summary

Many different therapies are applied to fight tumor disease. Blood-based biosources, like circulating tumor cells (CTCs), offer the opportunity to monitor the healing progression and the real-time response to the therapy. In this review, we analyze the outcomes of the clinical trials and scientific studies of prostate and breast cancer performed in the decade between April 2010 and April 2020. Additionally, we describe the abstracts from the 4th Advances in Circulating Tumor Cells (ACTC) meeting in 2019. We discuss the potential therapeutic opportunities related to the CTCs and the challenges ahead in the routine treatment of cancer.

Abstract

Prostate cancer and breast cancer are the most common cancers worldwide. Anti-tumor therapies are long and exhaustive for the patients. The real-time monitoring of the healing progression could be a useful tool to evaluate therapeutic response. Blood-based biosources like circulating tumor cells (CTCs) may offer this opportunity. Application of CTCs for the clinical diagnostics could improve the sequenced screening, provide additional valuable information of tumor dynamics, and help personalized management for the patients. In the past decade, CTCs as liquid biopsy (LB) has received tremendous attention. Many different isolation and characterization platforms are developed but the clinical validation is still missing. In this review, we focus on the clinical trials of circulating tumor cells that have the potential to monitor and stratify patients and lead to implementation into clinical practice.

To treat or not to treat: is it acceptable to avoid active therapies in advanced prostate cancer today?

Introduction: Recently, there has been a paradigm shift in the treatment of advanced prostate cancer (PCa) because the approval of a number of new agents has significantly improved overall survival. However, as PCa is a heterogeneous disease that may be more or less aggressive and patients may be more or less responsive to treatment, it is often debated whether or not it is acceptable to avoid active therapies.Areas covered: This review discusses different settings of advanced PCa.Expert opinion: In metastatic castration-resistant PCa, it is unethical not to use active treatments but the use of both androgen receptor targeting agents (ARTA) in sequence should be avoided in most patients and the use of the available agents for fourth-line treatment or beyond should only be considered for highly selected patients. In metastatic hormone-sensitive PCa, patients with de novo disease should receive one additional agent in combination with androgen deprivation therapy (ADT), whereas patients in relapse should be managed with ADT alone. In non-metastatic castration-resistant prostate cancer (PCa), all patients with a PSA doubling time of ≤6 months should receive one ARTA, whereas the others might wait until there is an acceleration in the kinetics of their PSA levels.

Liquid Biopsy Strategies to Distinguish Progression from Pseudoprogression and Radiation Necrosis in Glioblastomas

Liquid biopsy for the detection and monitoring of central nervous system tumors is of significant clinical interest. At initial diagnosis, the majority of patients with central nervous system tumors undergo magnetic resonance imaging (MRI), followed by invasive brain biopsy to determine the molecular diagnosis of the WHO 2016 classification paradigm. Despite the importance of MRI for long-term treatment monitoring, in the majority of patients who receive chemoradiation therapy for glioblastoma, it can be challenging to distinguish between radiation treatment effects including pseudoprogression, radiation necrosis, and recurrent/progressive disease based on imaging alone. Tissue biopsy-based monitoring is high risk and not always feasible. However, distinguishing these entities is of critical importance for the management of patients and can significantly affect survival. Liquid biopsy strategies including circulating tumor cells, circulating free DNA, and extracellular vesicles have the potential to afford significant useful molecular information at both the stage of diagnosis and monitoring for these tumors. Here, current liquid biopsy-based approaches in the context of tumor monitoring to differentiate progressive disease from pseudoprogression and radiation necrosis are reviewed.

PSA Kinetics as Prognostic Markers of Overall Survival in Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Abiraterone Acetate

Background

Abiraterone acetate (AA) is widely used in the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). However, a significant percentage of patients will still progress, highlighting the need to identify patients more likely to benefit from AA. Parameters linked to prostate-specific antigen (PSA) kinetics are promising prognostic markers. We have examined clinical and PSA-related factors potentially associated with overall survival (OS) in patients treated with AA.

Methods

Between 2011 and 2014, 104 patients with mCRPC treated with AA after progression to docetaxel at centers of the Catalan Institute of Oncology were included in this retrospective study. Patients were assessed monthly. Baseline characteristics and variables related to PSA kinetics were included in univariate and multivariate analyses of OS.

Results

Median OS was 16.4 months (range 12.4-20.6) for all patients. The univariate analysis identified the following baseline characteristics as significantly associated with OS: ECOG PS, location of metastases, time between starting androgen deprivation therapy and starting AA, time between stopping docetaxel treatment and starting AA, neutrophil-lymphocyte ratio (NLR), alkaline phosphatase levels, and PSA levels. Factors related to PSA kinetics associated with longer OS were PSA response >50%, early PSA response (>30% decline at four weeks), PSA decline >50% at week 12, PSA nadir <2.4ng/mL, time to PSA nadir >140 days, the combination of PSA nadir and time to PSA nadir, and low end-of-treatment PSA levels. The multivariate analysis identified ECOG PS (HR 37.46; p<0.001), NLR (HR 3.7; p<0.001), early PSA response (HR 1.22; p=0.002), and time to PSA nadir (HR 0.39; p=0.002) as independent prognostic markers.

Conclusion

Our results indicate an association between PSA kinetics, especially early PSA response, and outcome to AA after progression to docetaxel. Taken together with other factors, lack of an early PSA response could identify patients who are unlikely to benefit from AA and who could be closely monitored with a view to offering alternative therapies.

Liquid Biopsy is Instrumental for 3PM Dimensional Solutions in Cancer Management

One in every four deaths is due to cancer in Europe. In view of its increasing incidence, cancer became the leading cause of death and disease burden in Denmark, France, the Netherlands, and the UK. Without essential improvements in cancer prevention, an additional 775,000 cases of annual incidence have been prognosed until 2040. Between 1995 and 2018, the direct costs of cancer doubled from EUR 52 billion to EUR 103 billion in Europe, and per capita health spending on cancer increased by 86% from EUR 105 to EUR 195 in general, whereby Austria, Germany, Switzerland, Benelux, and France spend the most on cancer care compared to other European countries. In view of the consequent severe socio-economic burden on society, the paradigm change from a reactive to a predictive, preventive, and personalized medical approach in the overall cancer management is essential. Concepts of predictive, preventive, and personalized medicine (3PM) demonstrate a great potential to revise the above presented trends and to implement cost-effective healthcare that benefits the patient and society as a whole. At any stage, application of early and predictive diagnostics, targeted prevention, and personalization of medical services are basic pillars making 3PM particularly attractive for the patients as well as ethical and cost-effective healthcare. Optimal 3PM approach requires novel instruments such as well-designed liquid biopsy application. This review article highlights current achievements and details liquid biopsy approaches specifically in cancer management. 3PM-relevant expert recommendations are provided.

Identification of potential therapeutic targets in urothelial bladder carcinoma of Chinese population by targeted next-generation sequencing

Patients with urothelial carcinoma (UC) of the bladder have a high risk of death in China. However, a lack of comprehensive molecular profiling in Chinese Han population hinders the development of targeted therapies for bladder cancer. In our present study, we collected fresh bladder tumors from low-grade (T1, N0, M0, G1) non-muscle invasive bladder cancer (NMIBC) patients (n = 16) and high-grade (T2-4, N0, M0, Gx) muscle-invasive bladder cancer (MIBC) patients (n = 16) with their paired normal bladder tissues, and subjected the total genomic DNAs to targeted next-generation sequencing (NGS) for 94 cancer-associated genes. NGS results showed that 30.9% of detected genes (29/94) was mutated in 32 urothelial carcinoma bladder tissues. Furthermore, our results and ICGC database showed that FGFR3, KMT2D, TP53, KDM6A, and ARID1A were the most frequently mutated genes in UC patients. Of note, NMIBC and MIBC displayed distinguishable genomic alterations. FGFR3, KMT2D, AKT1, ARID1A, and STAG2 were the most frequently mutated genes in NMIBC patients, whereas mutations of TP53, CREBBP, FGFR3, KDM6A, KMT2D, and ARID1A were frequently detected in MIBC. Intriguingly, gene ontology and clustering analysis revealed that these frequently mutated genes were highly enriched in signaling pathways responsible for cancer development. Taken together, the mutation frequency of genes associated with UC development in NMIBC and MIBC was screened out in Chinese Han population and elucidation of the related mechanisms provides theoretical basis and technical support for the development of early diagnosis and therapeutic strategies in UC.

The Clinical Application and Potential Roles of Circulating Tumor Cells in Bladder Cancer and Prostate Cancer

Circulating tumor cells (CTCs) are considered to be promising biomarkers in malignant diseases. Recently, molecular profiles of CTCs in prostate cancer (PCa) and the role of CTCs in neoadjuvant chemotherapy and transurethral resections of bladder cancer (BCa) are intensely studied. However, localized PCa and nonmuscle-invasive BCa are less investigated and discussed. Moreover, the benefit and feasibility of clinical applications of CTCs should be critically questioned and reevaluated. This review focuses mainly on clinical issues and lesser on methodologies, and summarizes the quintessence of available works dealing with clinical applications of CTCs in PCa and BCa management.

Emerging promising biomarkers for treatment decision in metastatic castration-resistant prostate cancer

Prostate cancer is one of the most common causes of death in males. Even if treatment is often of curative intent in early stages of the disease, up to 50% of patients relapse after primary therapy. Moreover, 10% to 15% of patients present in a primary metastatic stage of disease. In the past years the treatment landscape of metastatic castration-resistant prostate cancer expanded due to the development of second-generation antiandrogens (abiraterone acetate, enzalutamide), chemotherapeutic agents and radium-223. With the availability of several therapeutic lines, we are now confronted with the problem of choosing the most suitable therapy in each state of disease. As often observed in clinical routine, prostate specific antigen is not sufficient for early prediction of a therapy response. Furthermore, biomarkers for prediction of the optimal first-line therapy are badly needed in order to avoid primary resistance. Therefore, the present short review article gives an overview of currently available clinical and preclinical biomarkers for treatment response to metastatic castration-resistant prostate cancer therapeutic agents with the aim of providing support for a personalized decision-making process in everyday use.

Molecular analysis of circulating tumor cells of metastatic castration-resistant Prostate Cancer Patients receiving 177Lu-PSMA-617 Radioligand Therapy

Rationale: Lu-177-PSMA-617 radioligand therapy (RLT) is currently under approval for treatment of metastatic castration resistant prostate cancer (mCRPC) patients with late stage disease. However, previous studies demonstrated both heterogeneity of prostate specific membrane antigen (PSMA) expression, as well as response to PSMA treatment among mCRPC patients. Thus, there is an unmet need for identifying predictive parametres prior or under PSMA-RLT treatment. We therefore aimed to correlate several clinical and molecular parameters with response to PSMA treatment in a cohort of mCRPC patients undergoing PSMA RLT followed by a detailed analysis of promising candidates.

Methods: Nineteen patients, median age 68.8 years (range: 56.9 - 83.3) with mCRPC were included in this study. We performed baseline analysis of clinical parameters based on PSMA PET/CT, (metabolic tumor volume (MTV), total tumor volume (TTV)), serum PSA, ALP, LDH and gene expression analysis of circulating tumor cells (expression of AR full length (AR-FL), AR splice variant 7 (AR-V7), PSA and PSMA) as well as common markers for neuroendocrine differentiation (NED).

Results: Patients presented with bone, lymph node, and visceral metastases (89%, 68%, and 21%, respectively). All patients were pretreated with docetaxel, either abiraterone or enzalutamide, or both. Biochemical response in terms of PSA decline ≥50 or ≥30% was observed in 42% and 63%, respectively. There were significant correlations between PSA and PSMA mRNA expression, as well as tumor volumes (both MTV and TTV), AR-FL and AR-V7 mRNA expression. However, there was no correlation with response to PSMA treatment. Furthermore, none of these parameters was significantly correlated with baseline serum PSA values. Common NED markers were shown to be specifically high expressed and revealed impact on OS independent from AR-V7 gene expression.

Conclusion: We demonstrate that AR-FL and its splice variant AR-V7 might serve as prognostic biomarkers displaying high tumor burden in mCRPC patient prior to PSMA-RLT. Contrary, PSMA, which has been discussed as a biomarker for PSMA targeted treatment, does not display strong prognostic ability - at least on the mRNA level. Surprisingly, none of these parameters correlates to response to PSMA treatment. In contrast, commom NED markers such as SYP and ENO2 as well as FOXA1 expression level seem to predict OS, but not PFS, more reliably. We admit that a limitation of our study is the focus on mRNA expression of potential biomarkers only. Further investigations analyzing the potential role of protein expression of these markers are therefore warranted.

Clinical significance of circulating tumor cells detection in renal cell carcinoma with thrombus: A STROBE-compliant study

The aim of the study was to evaluate the potential role of circulating tumor cell (CTC) detection in the surgical assessment of renal cell carcinoma (RCC) patients with thrombi.Nine patients diagnosed with renal mass and thrombi were enrolled from June 2018 to January 2019. Blood samples were collected for CTC detection using SE-iFISH assay. CD45, DAPI, programmed death ligand 1, and fluorescence in situ hybridization with the centromere of chromosome 8 (CEP8) were immune-stained for analysis. Patient demographics, clinical features, pathological characteristics, and CTC detection results were extracted for analysis.Seven of 9 patients (77.8%) had 12 detectable CTCs, 5 of which were with CEP8-positive signal ≥5 and the others were CEP8-positive signal = 3. All 3 patients (100%) with IVC invasion had detectable CTCs, whereas CTCs were detected in 4 of 6 patients (66.7%) without IVC invasion. CEP8 analysis revealed that CTCs in IVC invasion patients were all of CEP8-positive signal ≥5 status, whereas only half of the CTCs in patients without IVC invasion were of CEP8-positive signal ≥5 pattern.In conclusion, both CTC subtype and total CTC number may serve as a marker for predicting inferior vena cava invasion in RCC patients.

Liquid Biopsy Serial Monitoring of Treatment Responses and Relapse in Advanced Esophageal Squamous Cell Carcinoma

(1) Background: Early predictive markers to track treatment responses are needed for advanced esophageal squamous cell carcinoma (ESCC) patients. We examined the prognostication and risk stratification role of liquid biopsy serial monitoring for this deadly cancer. (2) Methods: Circulating tumor cells (CTCs) and plasma cell-free DNA (cfDNA) were isolated from 60 ESCC patients treated by chemotherapy (CT) at five serial timepoints: baseline (CTC1/cfDNA1), CT pre-cycle III (CTC2/cfDNA2), CT post-cycle IV, end of CT and relapse. (3) Results: In 45/57 ESCC patients with evaluable CTC counts at CT pre-cycle III, positive CTC2 (≥3 CTCs) is independently associated with response at interim reassessment and progression-free survival (PFS) in multivariate analysis. In 42/57 ESCC patients with changes of CTC1/CTC2 and cfDNA1/cfDNA2, patients categorized into four risk groups based on the number of favorable and unfavorable changes of CTC1/CTC2 and cfDNA1/cfDNA2, were independently associated with overall survival (OS) by multivariate analysis. (4) Conclusions: CTC counts at pre-cycle III are independently associated with response at interim reassessment and PFS. Combined changes of CTC counts and cfDNA levels from baseline to pre-cycle III are independently associated with OS. Longitudinal liquid biopsy serial monitoring provides complementary information for prediction and prognosis for CT responses in advanced ESCC.

Clinical utility of serial analysis of circulating tumour cells for detection of minimal residual disease of metastatic nasopharyngeal carcinoma

Background

Nasopharyngeal carcinoma (NPC) is an important cancer in Hong Kong. We aim to utilise liquid biopsies for serial monitoring of disseminated NPC in patients to compare with PET-CT imaging in detection of minimal residual disease.

Method

Prospective serial monitoring of liquid biopsies was performed for 21 metastatic patients. Circulating tumour cell (CTC) enrichment and characterisation was performed using a sized-based microfluidics CTC chip, enumerating by immunofluorescence staining, and using target-capture sequencing to determine blood mutation load. PET-CT scans were used to monitor NPC patients throughout their treatment according to EORTC guidelines.

Results

The longitudinal molecular analysis of CTCs by enumeration or NGS mutational profiling findings provide supplementary information to the plasma EBV assay for disease progression for good responders. Strikingly, post-treatment CTC findings detected positive findings in 75% (6/8) of metastatic NPC patients showing complete response by imaging, thereby demonstrating more sensitive CTC detection of minimal residual disease. Positive baseline, post-treatment CTC, and longitudinal change of CTCs significantly associated with poorer progression-free survival by the Kaplan–Meier analysis.

Conclusions

We show the potential usefulness of application of serial analysis in metastatic NPC of liquid biopsy CTCs, as a novel more sensitive biomarker for minimal residual disease, when compared with imaging.

Circulating tumour cell enumeration does not correlate with Miller-Payne grade in a cohort of breast cancer patients undergoing neoadjuvant chemotherapy

Purpose

The association between pathological complete response (pCR) in patients receiving neoadjuvant chemotherapy (NAC) for breast cancer and Circulating Tumour Cells (CTCs) is not clear. The aim of this study was to assess whether CTC enumeration could be used to predict pathological response to NAC in breast cancer as measured by the Miller–Payne grading system.

Methods

Twenty-six patients were recruited, and blood samples were taken pre- and post-NAC. CTCs were isolated using the ScreenCell device and stained using a modified Giemsa stain. CTCs were enumerated by 2 pathologists and classified as single CTCs, doublets, clusters/microemboli and correlated with the pathological response as measured by the Miller–Payne grading system. χ² or ANOVA was performed in SPSS 24.0 statistics software for associations.

Results

89% of patients had invasive ductal carcinoma (IDC) and 11% invasive lobular carcinoma (ILC). At baseline 85% of patients had CTCs present, median 7 (0–161) CTCs per 3 ml of whole blood. Post-chemotherapy, 58% had an increase in CTCs. This did not correlate with the Miller–Payne grade of response. No significant association was identified between the number of CTCs and clinical characteristics; however, we did observe a correlation between pre-treatment CTC counts and body mass index, p < 0.05.

Conclusions

Patients with a complete response to NAC still had CTCs present, suggesting enumeration is not sufficient to aid surgery stratification. Additional characterisation and larger studies are needed to further characterise CTCs isolated pre- and post-chemotherapy. Long-term follow-up of these patients will determine the significance of CTCs in NAC breast cancer patients.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05658-7) contains supplementary material, which is available to authorized users.

Characterization of a novel automated microfiltration device for the efficient isolation and analysis of circulating tumor cells from clinical blood samples

The detection and analysis of circulating tumor cells (CTCs) may enable a broad range of cancer-related applications, including the identification of acquired drug resistance during treatments. However, the non-scalable fabrication, prolonged sample processing times, and the lack of automation, associated with most of the technologies developed to isolate these rare cells, have impeded their transition into the clinical practice. This work describes a novel membrane-based microfiltration device comprised of a fully automated sample processing unit and a machine-vision-enabled imaging system that allows the efficient isolation and rapid analysis of CTCs from blood. The device performance was characterized using four prostate cancer cell lines, including PC-3, VCaP, DU-145, and LNCaP, obtaining high assay reproducibility and capture efficiencies greater than 93% after processing 7.5 mL blood samples spiked with 100 cancer cells. Cancer cells remained viable after filtration due to the minimal shear stress exerted over cells during the procedure, while the identification of cancer cells by immunostaining was not affected by the number of non-specific events captured on the membrane. We were also able to identify the androgen receptor (AR) point mutation T878A from 7.5 mL blood samples spiked with 50 LNCaP cells using RT-PCR and Sanger sequencing. Finally, CTCs were detected in 8 out of 8 samples from patients diagnosed with metastatic prostate cancer (mean ± SEM = 21 ± 2.957 CTCs/mL, median = 21 CTCs/mL), demonstrating the potential clinical utility of this device.

Delta-like protein 3 expression and therapeutic targeting in neuroendocrine prostate cancer

Histologic transformation to small cell neuroendocrine prostate cancer occurs in a subset of patients with advanced prostate cancer as a mechanism of treatment resistance. Rovalpituzumab tesirine (SC16LD6.5) is an antibody-drug conjugate that targets delta-like protein 3 (DLL3) and was initially developed for small cell lung cancer. We found that DLL3 is expressed in most of the castration-resistant neuroendocrine prostate cancer (CRPC-NE) (36 of 47, 76.6%) and in a subset of castration-resistant prostate adenocarcinomas (7 of 56, 12.5%). It shows minimal to no expression in localized prostate cancer (1 of 194) and benign prostate (0 of 103). DLL3 expression correlates with neuroendocrine marker expression, RB1 loss, and aggressive clinical features. DLL3 in circulating tumor cells was concordant with matched metastatic biopsy (87%). Treatment of DLL3-expressing prostate cancer xenografts with a single dose of SC16LD6.5 resulted in complete and durable responses, whereas DLL3-negative models were insensitive. We highlight a patient with neuroendocrine prostate cancer with a meaningful clinical and radiologic response to SC16LD6.5 when treated on a phase 1 trial. Overall, our findings indicate that DLL3 is preferentially expressed in CRPC-NE and provide rationale for targeting DLL3 in patients with DLL3-positive metastatic prostate cancer.

Dual-procedural separation of CTCs in cutaneous melanoma provides useful information for both molecular diagnosis and prognosis

Background:

Circulating tumor cells (CTCs) have recently emerged as a new dynamic soluble marker for several malignancies including cutaneous melanoma (CM) and are suitable for prognostic evaluations and treatment monitoring. However, to date many limitations still hamper the wide-scale application of CTCs in CM setting, including the lack of standardized methods as well as both low levels and heterogeneity of these cells.

Methods:

We developed a protocol for CTC detection in CM based on immune-magnetic sorting to deplete CD45-, CD31- or CD34-positive cells, followed by dielectrophoretic DEPArray separation according to cell morphology and immunophenotype. To this end, we explored the expression of melanoma stem cell antigens (CD271, ABCB5, and RANK) and the epithelial-to-mesenchymal transition markers (N-Cad, -CD44, and -MCAM/CD146) on CTCs from 17 stage IV CM patients, and investigated their BRAF mutational status by droplet digital PCR.

Results:

The number of CTCs isolated from CM patients ranged from 2 to 91 cells (38 ± 6.4) with respect to healthy donors (p < 0.0002). To confirm the melanoma origin of isolated cells, we observed an 80% agreement between their BRAF^V600 mutational status and matched primary tumors. The characterization of the immune phenotype of isolated cells revealed high interindividual and intraindividual heterogeneity that was found to correlate with the clinical outcome.

Conclusions:

The dual-step protocol of immune-magnetic sorting and subsequent dielectrophoretic DEPArray separation, turned out to be a suitable method to isolate viable CTCs from stage IV melanoma patients and enabled quantitative and qualitative analyses on these cells, which may deserve prospective evaluation for potential use in the clinical practice.

The combination of CTCs and CEA can help guide the management of patients with SPNs suspected of being lung cancer

Objective

Solitary pulmonary nodules (SPNs) is a common radiographic finding and require further evaluation because of the possibility of lung cancer. This study aimed to determine the sensitivity and specificity of circulating tumour cells (CTCs) as a marker for the diagnosis of SPNs and the integration of CTCs, carcinoembryonic antigen (CEA) and imaging findings to improve the sensitivity and specificity of diagnosis in patients with SPNs suspected of being lung cancer.

Method

For the serum biomarker assay, the concentration of CEA was measured by an automated electrochemiluminescence analyzer. CTCs were collected from 6 ml of blood by the SE i-FISH method, which detects the gene copy number in eight chromosomes and the tumour-associated antigen CK18.

Results

With a threshold of 6 CTC units, the method showed a sensitivity of 67.1% and a specificity of 56.5% in the diagnosis of NSCLC, especially in the upper lobe, in which the diagnostic strength was the highest (P < 0.01). CTCs, CEA and nodule type had the highest diagnostic efficacy (area under the curve, 0.827; 95% confidence interval, 0.752–0.901) in patients with SPNs being suspected lung cancer. Combining CTCs (cut-off value 12 units) with CEA (1.78 ng/ml), the method showed a sensitivity of 77.8% and a specificity of 90% in the diagnosis of NSCLC, especially in the upper lobe, subsolid nodules and nodules ≥8 mm.

Conclusions

Our results demonstrated that CTCs are feasible diagnostic biomarkers in patients with SPNs, especially in the upper lobe. Furthermore, CTCs combined with CEA showed higher diagnostic efficacy in the upper lobe, subsolid nodules and nodules ≥8 mm.