Circulating tumour cells as prognostic markers in progressive, castration-resistant prostate cancer: a reanalysis of IMMC38 trial data

Genomic and transcriptomic sequencing in prostate cancer

PURPOSE OF REVIEW

Genomic and transcriptomic sequencing technologies have revolutionized our ability to characterize prostate cancer at the molecular level. The underlying premise of next-generation sequencing technologies and their current and evolving applications in prostate cancer management are provided in the review.

RECENT FINDINGS

Improved methodologies are allowing timely sequencing of the coding regions or both the coding and noncoding regions of the genome to help identify potential mutations and structural variations in the prostate cancer genome, some of which are currently also targetable therapeutically. DNA microarray- based differential gene expression has been supplanted by RNA sequencing (RNA-seq), which not only allows for more accurate quantitation but also nucleotide-level resolution to investigate the entire transcriptome, including alternative gene spliced transcripts and noncoding RNA transcripts, whose full clinical implications have yet to be fully understood and realized. Gene classifier platforms that predict risk of recurrence or metastasis are being incorporated into prostate cancer management algorithms. In the appropriate clinical context, not only somatic but also germline mutation testing is being recommended.

SUMMARY

Continued clinical integration of sequencing technologies and ongoing research will lead to improved understanding of prostate cancer biology and prostate cancer treatment.

Clinical and Translational Results from PORTER, a Multicohort Phase I Platform Trial of Combination Immunotherapy in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Current immune checkpoint therapies offer limited benefits for metastatic castration-resistant prostate cancer. Novel combinations may enhance immunotherapy efficacy.

PATIENTS AND METHODS

We conducted an open-label, noncomparative platform trial (NCT03835533) in metastatic castration-resistant prostate cancer to assess nivolumab-based combinations. The cohorts were as follows: (A) bempegaldesleukin 0.006 mg/kg and nivolumab 360 mg i.v. every 3 weeks; (B) stereotactic body radiotherapy 30 to 50 Gy, CDX-301 75 μg/kg s.c. for 5 days, poly-ICLC 1 mg intramuscularly weekly twice for 3 weeks, and nivolumab 480 mg every 4 weeks; and (C) CDX-301 75 μg/kg for 10 days, INO-5151 3 mg intramuscularly on lead-in day 8, day 1 of cycles 1 to 3, and then every 12 weeks, and nivolumab 480 mg every 4 weeks. The primary endpoint was safety; secondary endpoints included composite response rate (radiographic, PSA, or circulating tumor cell responses), 6-month disease control rate, progression-free survival, and overall survival. Serial blood and tissue samples were analyzed for pharmacodynamics and association with disease control.

RESULTS

A total of 43 patients were enrolled (n = 14, 15, and 14 in cohorts A, B, and C, respectively). Grade 3 to 4 treatment-related adverse events occurred in 10 (71%), 2 (13%), and 2 (14%) patients, respectively, with one grade 5 treatment-related adverse event in cohort A. Composite response rates were 7% (1/14), 33% (5/15), and 7% (1/14). Across cohorts, 6-month disease control was associated with preexisting memory/regulatory T cells, TNFα, and other inflammatory pathways.

CONCLUSIONS

Cohort B, which combined radiotherapy with CDX-301, poly-ICLC, and nivolumab, demonstrated encouraging clinical activity. Preexisting rather than treatment-induced immune activation was associated with clinical benefit across cohorts, highlighting the importance of baseline immune fitness.

The Role of ctDNA for Diagnosis and Histological Prediction in Early Stage Non-Small-Cell Lung Cancer: A Narrative Review

Background: Circulating tumor DNA (ctDNA) may be released from neoplastic cells into biological fluids through apoptosis, necrosis, or active release. In patients with non-small-cell lung cancer (NSCLC), ctDNA analysis is being introduced in clinical practice only for advanced disease management. Nevertheless, an interesting and promising field of application is the analysis of ctDNA in the management of early stage non-small-cell lung cancer, both for evaluation before treatment, such as diagnosis and screening, and for prediction of histology or pathological features. Methods: A thorough review of the literature published between 2000 and 2024 was performed on PubMed, utilizing the advanced search feature to narrow down titles and abstracts containing the following keywords: ctDNA, early stage, and NSCLC. A total of 20 studies that met all inclusion criteria were chosen for this review. Results: In this review, we summarize the increasing evidence suggesting that ctDNA has potential clinical applications in the management of patients with early stage NSCLC. ctDNA levels in early stage cancers are very low, posing many technical challenges in improving the detection rate and sensitivity, especially in clinical practice, if it is to be implemented for early detection. Presently, the main limitation of ctDNA experimental and clinical studies, especially in early stage settings, is the lack of definitive standardization and consensus regarding methodology, the absence of systematically validated analyses, and the lack of adoption of sensitive approaches. Conclusions: Possible applications of this analyte open up new fields of diagnosis, treatment, and follow up, which are less invasive and more precise than other approaches currently in use, especially in early stage NSCLC patients.

Prognostic value of circulating tumor cells in oligorecurrent hormone-sensitive prostate cancer patients undergoing stereotactic body radiation therapy

BACKGROUND

Stereotactic body radiation therapy (SBRT) is an effective metastasis-directed therapy for managing oligometastatic prostate cancer patients. However, it lacks reliable biomarkers for risk stratification. Circulating Tumor Cells (CTC) show promise as minimally invasive prognostic indicators. This study evaluates the prognostic value of CTC in oligorecurrent hormone-sensitive prostate cancer (orHSPC).

METHODS

orHSPC patients with 1-3 nodal and/or bone metastases undergoing SBRT were enrolled (N = 35), with a median follow-up time of 42.1 months. CTC levels were measured at baseline (T0), 1 month (T1), and 3 months (T2) post-SBRT using a novel metabolism-based assay. These levels were correlated with clinical outcomes through Cox-regression and Kaplan-Meier analyses.

RESULTS

Median CTC counts were 5 at T0, 8 at T1, and 5 at T2 with no significant variation over time. Multivariate analysis identified high (≥5/7.5 mL) T0 CTC counts (HR 2.9, 95% CI 1.3-6.5, p = 0.01, median DPFS 29.7 vs. 14.0 months) and having more than one metastasis (HR 3.9, 95% CI 1.8-8.6, p < 0.005, median DPFS 34.1 vs. 10.7 months) as independent predictors of distant progression-free survival (DPFS). CTC assessment successfully stratified patients with a single metastasis (HR 3.4, 95% CI 1.1-10.2, p = 0.03, median DPFS 42.1 vs. 16.7 months), but not those with more than one metastasis. Additionally, a combined score based on CTC levels and the number of metastases effectively stratified patients.

CONCLUSION

The study demonstrates that hypermetabolic CTC could enhance risk stratification in orHSPC patients undergoing SBRT, particularly in patients with limited metastatic burden, potentially identifying patients with indolent disease who are suitable for tailored SBRT interventions.

Circulating Tumor Cell Count and Overall Survival in Patients With Metastatic Hormone-Sensitive Prostate Cancer

Importance

In metastatic hormone-sensitive prostate cancer (mHSPC), new first-line combination therapies have enhanced overall survival (OS), but clinical outcomes for individual patients vary greatly and are difficult to predict. Peripheral blood circulating tumor cell (CTC) count is the most extensively validated prognostic liquid biomarker in metastatic castration-resistant prostate cancer (mCRPC), and recent studies have suggested that it may also be informative in mHSPC.

Objective

To examine the prognostic value of CTC count in men with mHSPC.

Design, Setting, and Participants

In this prognostic study, peripheral blood was drawn at registration (baseline) and at progression to mCRPC in the S1216 study (March 1, 2013, to July 15, 2017), a phase 3, prospective, randomized clinical trial in men with mHSPC. The CTCs were enumerated using a US Food and Drug Administration-cleared isolation platform. Counts were categorized as 0, 1 to 4, or 5 or more CTCs per 7.5 mL based on the prognostic value of these cut points in prior studies. The data analysis was performed between October 28, 2022, and June 15, 2023.

Exposure

Metastatic hormone-sensitive prostate cancer.

Main Outcomes and Measures

Circulating tumor cell count was evaluated for an association with 3 prespecified trial end points: OS, progression-free survival, and 7-month prostate-specific antigen, after adjusting for other baseline covariates using proportional hazards and logistic regression models.

Results

Of 1313 S1216 participants (median [IQR] age, 68 [44-92] years), evaluable samples from 503 (median [IQR] age, 69 [46-90] years) with newly diagnosed mHSPC were collected at baseline, and 93 samples were collected at progression. Baseline counts were 5 or more CTCs per 7.5 mL in 60 samples (11.9%), 1 to 4 CTCs per 7.5 mL in 107 samples (21.3%), and 0 CTCs per 7.5 mL in 336 samples (66.8%). Median OS for men with 5 or more CTCs per 7.5 mL was 27.9 months (95% CI, 24.1-31.2 months) compared with 56.2 months (95% CI, 45.7-69.8 months) for men with 1 to 4 CTCs per 7.5 mL and not reached at 78.0 months follow-up for men with 0 CTCs per 7.5 mL. After adjusting for baseline clinical covariates, men with 5 or more CTCs per 7.5 mL at baseline had a significantly higher hazard of death (hazard ratio, 3.22; 95% CI, 2.22-4.68) and disease progression (hazard ratio, 2.46; 95% CI, 1.76-3.43) and a lower likelihood of prostate-specific antigen complete response (odds ratio, 0.26; 95% CI, 0.12-0.54) compared with men with 0 CTCs per 7.5 mL at baseline. Adding baseline CTC count to other known prognostic factors (covariates only: area under the curve, 0.73; 95% CI, 0.67-0.79) resulted in an increased prognostic value for 3-year survival (area under the curve, 0.79; 95% CI, 0.73-0.84).

Conclusions and Relevance

In this prognostic study, the findings validate CTC count as a prognostic biomarker that improved upon existing prognostic factors and estimated vastly divergent survival outcomes regardless of subsequent lines of therapy. As such, baseline CTC count in mHSPC may serve as a valuable noninvasive biomarker to identify men likely to have poor survival who may benefit from clinical trials of intensified or novel regimens.

Castration-resistant prostate cancer monitoring by cell-free circulating biomarkers

Background

Prostate cancer is the second leading cause of male cancer-related deaths in Western countries, which is predominantly attributed to the metastatic castration-resistant stage of the disease (CRPC). There is an urgent need for better prognostic and predictive biomarkers, particularly for androgen receptor targeted agents and taxanes.

Methods

We have searched the PubMed database for original articles and meta-analyses providing information on blood-based markers for castration-resistant prostate cancer monitoring, risk group stratification and prediction of therapy response.

Results

The molecular markers are discussed along with the standard clinical parameters, such as prostate specific antigen, lactate dehydrogenase or C-reactive protein. Androgen receptor (AR) alterations are commonly associated with progression to CRPC. These include amplification of AR and its enhancer, point mutations and splice variants. Among DNA methylations, a novel 5-hydroxymethylcytosine activation marker of TOP2A and EZH2 has been identified for the aggressive disease. miR-375 is currently the most promising candidate among non-coding RNAs and sphingolipid analysis has recently emerged as a novel approach.

Conclusions

The promising biomarkers have the potential to improve the care of metastatic prostate cancer patients, however, they need further validation for routine implementation.

Circulating tumor cells: from new biological insights to clinical practice

The primary reason for high mortality rates among cancer patients is metastasis, where tumor cells migrate through the bloodstream from the original site to other parts of the body. Recent advancements in technology have significantly enhanced our comprehension of the mechanisms behind the bloodborne spread of circulating tumor cells (CTCs). One critical process, DNA methylation, regulates gene expression and chromosome stability, thus maintaining dynamic equilibrium in the body. Global hypomethylation and locus-specific hypermethylation are examples of changes in DNA methylation patterns that are pivotal to carcinogenesis. This comprehensive review first provides an overview of the various processes that contribute to the formation of CTCs, including epithelial-mesenchymal transition (EMT), immune surveillance, and colonization. We then conduct an in-depth analysis of how modifications in DNA methylation within CTCs impact each of these critical stages during CTC dissemination. Furthermore, we explored potential clinical implications of changes in DNA methylation in CTCs for patients with cancer. By understanding these epigenetic modifications, we can gain insights into the metastatic process and identify new biomarkers for early detection, prognosis, and targeted therapies. This review aims to bridge the gap between basic research and clinical application, highlighting the significance of DNA methylation in the context of cancer metastasis and offering new avenues for improving patient outcomes.

Fast and efficient isolation of murine circulating tumor cells using screencell technology for pre-clinical analyzes

Circulating tumor cells (CTCs) represent a rare and heterogeneous population of cancer cells that are detached from the tumor site and entered blood or lymphatic circulation. Once disseminated in distant tissues, CTCs could remain dormant or create a tumor mass causing serious danger for patients. Many technologies exist to isolate CTCs from patients' blood samples, mostly based on microfluidic systems or by sorting them according to their surface antigens, notably EpCAM, and/or cytokeratins for carcinoma. ScreenCell has developed an easy-to-use, antigen-independent, rapid, cost-effective, and efficient technology that isolates CTCs according to their bigger size compared to the blood cells. This study provides the technical information necessary to isolate and characterize CTCs from mouse blood. By using blood samples from transgenic mice with breast cancer or from WT mice in which we spiked cancer cells, we showed that ScreenCell technology is compatible with standard EDTA blood collection tubes. Furthermore, the ScreenCell Cyto kit could treat up to 500 µl and the ScreenCell MB kit up to 200 µl of mouse blood. As the ScreenCell MB kit captures unaltered live CTCs, we have shown that their DNA could be efficiently extracted, and the isolated cells could be grown in culture. In conclusion, ScreenCell provides a rapid, easy, antigen-independent, cost-effective, and efficient technology to isolate and characterize CTCs from the blood samples of cancer patients and murine models. Thanks to this technology CTCs could be captured fixed or alive. Murine cancer models are extensively used in pre-clinical studies. Therefore, this study demonstrates the crucial technical points necessary while manipulating mouse blood samples using ScreenCell technology.

Revisiting the standards of cancer detection and therapy alongside their comparison to modern methods

In accordance with the World Health Organization data, cancer remains at the forefront of fatal diseases. An upward trend in cancer incidence and mortality has been observed globally, emphasizing that efforts in developing detection and treatment methods should continue. The diagnostic path typically begins with learning the medical history of a patient; this is followed by basic blood tests and imaging tests to indicate where cancer may be located to schedule a needle biopsy. Prompt initiation of diagnosis is crucial since delayed cancer detection entails higher costs of treatment and hospitalization. Thus, there is a need for novel cancer detection methods such as liquid biopsy, elastography, synthetic biosensors, fluorescence imaging, and reflectance confocal microscopy. Conventional therapeutic methods, although still common in clinical practice, pose many limitations and are unsatisfactory. Nowadays, there is a dynamic advancement of clinical research and the development of more precise and effective methods such as oncolytic virotherapy, exosome-based therapy, nanotechnology, dendritic cells, chimeric antigen receptors, immune checkpoint inhibitors, natural product-based therapy, tumor-treating fields, and photodynamic therapy. The present paper compares available data on conventional and modern methods of cancer detection and therapy to facilitate an understanding of this rapidly advancing field and its future directions. As evidenced, modern methods are not without drawbacks; there is still a need to develop new detection strategies and therapeutic approaches to improve sensitivity, specificity, safety, and efficacy. Nevertheless, an appropriate route has been taken, as confirmed by the approval of some modern methods by the Food and Drug Administration.

A Molecular Voyage: Multiomics Insights into Circulating Tumor Cells

Circulating tumor cells (CTCs) play a pivotal role in metastasis, the leading cause of cancer-associated death. Recent improvements of CTC isolation tools, coupled with a steady development of multiomics technologies at single-cell resolution, have enabled an extensive exploration of CTC biology, unlocking insights into their molecular profiles. A detailed molecular portrait requires CTC interrogation across various levels encompassing genomic, epigenetic, transcriptomic, proteomic and metabolic features. Here, we review how state-of-the-art multiomics applied to CTCs are shedding light on how cancer spreads. Further, we highlight the potential implications of CTC profiling for clinical applications aimed at enhancing cancer diagnosis and treatment.

SIGNIFICANCE

Exploring the complexity of cancer progression through cutting-edge multiomics studies holds the promise of uncovering novel aspects of cancer biology and identifying therapeutic vulnerabilities to suppress metastasis.

Prostein expression on circulating tumor cells as a prognostic marker in metastatic castration-resistant prostate cancer

BACKGROUND

Identification of emerging molecular biomarkers on circulating tumor cells (CTCs) represents an attractive feature of liquid biopsy that facilitates precision and tailored medicine in the management of metastatic castration-resistant prostate cancer (mCRPC). Prostein is an androgen-regulated transmembrane protein with high prostate specificity. Prostein-positive circulating tumor cell (CTC) was recently suggested to have diagnostic potential; however, no study has been conducted to evaluate its prognostic value in mCRPC.

METHODS

CTCs from mCRPC patients were enumerated using the CellSearch System. Prostein-positive CTCs were identified by immunostaining results. The relationships between prostein expression on CTCs and PSA response rate, PSA progression-free survival (PSA-PFS), radiographic progression-free survival (PFS), and overall survival (OS) were tested by Fisher's exact test or evaluated using Kaplan-Meier and multivariate Cox analyses.

RESULTS

Prostein-positive CTCs were identified in 31 of 87 baseline samples from mCRPC patients and 16 of 51 samples collected at the first follow-up visit. PSA response rates were significantly lower in baseline prostein-positive patients (0%, 0/31) than in prostein-negative patients (19.6%, 11/56) (p = 0.007). The 31 prostein-positive patients had significantly shorter PSA-PFS (p < 0.001), radiographic PFS (p < 0.001), and OS (p = 0.018), compared to the 56 prostein-negative patients at baseline. The association with PSA-PFS maintained its significance (p = 0.028) in multivariate analyses. Analyzing prostein expression at the first follow-up as well as the conversion of prostein expression from baseline to follow-up samples not only confirmed the association with PSA-PFS, but also demonstrated prognostic significance with OS.

CONCLUSION

Our study provides the first evidence to support the potential of prostein expression on CTCs to serve as a novel prognostic marker in mCRPC patients. Future large-scale prospective studies are needed to validate our findings.

Circulating tumor cell detection may offer earlier diagnosis in patients suspected of asbestos-related lung cancer

Asbestos-Related Lung Cancer (ARLC) presents ongoing diagnostic challenges despite improved imaging technologies. The long latency period, coupled with limited access to occupational and environmental data along with the confounding effects of smoking and other carcinogens adds complexity to the diagnostic process. Compounding these challenges is the absence of a specific histopathologic or mutational signature of ARLC. A correlation between PD-L1 expression and response to immune checkpoint inhibition has not yet been proven. Thus, new biomarkers are needed to allow accurate diagnoses of ARLC, to enable prognostication and to offer personalized treatments. Liquid biopsies, encompassing circulating DNA and circulating tumor cells (CTCs), have gained attention as novel diagnostic methods in lung cancer to screen high-risk populations including those exposed to asbestos. CTCs can be enumerated and molecularly profiled to provide predictive and prognostic information. CTC studies have not been undertaken in populations at risk of ARLC to date. The potential of CTCs to provide real-time molecular insight into ARLC biology may significantly improve the diagnosis and management of ARLC patients.

Liquid biopsy to personalize treatment for metastatic prostate cancer

Liquid biopsy is an innovative approach that provides a more complete understanding of treatment response and prognosis in monitoring metastatic prostate cancer. It complements invasive tissue biopsy and involves the assessment of various biomarkers in body fluids such as blood, semen, and urine. Liquid biopsy analyzes circulating tumor cells, extracellular vesicles, circulating tumor DNA, and the secretome. This is particularly important given the heterogeneity of prostate cancer and the need for better prognostic biomarkers. Liquid biopsy can personalize the treatment of homonosensitive and castration-resistant metastatic prostate cancer by acting as a predictive and prognostic tool. This review discusses various biomarkers, assay techniques, and potential applications in daily clinical practice, highlighting the exciting possibilities that this emerging field holds for improving patient outcomes.

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 Role of Circulating Tumor Cells as a Liquid Biopsy for Cancer: Advances, Biology, Technical Challenges, and Clinical Relevance

Cancer remains a leading cause of mortality worldwide, with metastasis significantly contributing to its lethality. The metastatic spread of tumor cells, primarily through the bloodstream, underscores the importance of circulating tumor cells (CTCs) in oncological research. As a critical component of liquid biopsies, CTCs offer a non-invasive and dynamic window into tumor biology, providing invaluable insights into cancer dissemination, disease progression, and response to treatment. This review article delves into the recent advancements in CTC research, highlighting their emerging role as a biomarker in various cancer types. We explore the latest technologies and methods for CTC isolation and detection, alongside novel approaches to characterizing their biology through genomics, transcriptomics, proteomics, and epigenetic profiling. Additionally, we examine the clinical implementation of these findings, assessing how CTCs are transforming the landscape of cancer diagnosis, prognosis, and management. By offering a comprehensive overview of current developments and potential future directions, this review underscores the significance of CTCs in enhancing our understanding of cancer and in shaping personalized therapeutic strategies, particularly for patients with metastatic disease.

Clinical applications of cerebrospinal fluid liquid biopsies in central nervous system tumors

For patients with central nervous system (CNS) malignancies, liquid biopsies of the cerebrospinal fluid (CSF) may offer an unparalleled source of information about the tumor, with much less risk than traditional biopsies. Two techniques have been adapted to CSF in clinical settings: circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). CTCs have been employed mostly as a diagnostic tool for leptomeningeal metastases in epithelial tumors, although they may also have value in the prognostication and monitoring of this disease. The ctDNA technology has been studied in a variety of primary and metastatic brain and spinal cord tumors, where it can be used for diagnosis and molecular classification, with some work suggesting that it may also be useful for longitudinal tracking of tumor evolution or as a marker of residual disease. This review summarizes recent publications on the use of these two tests in CSF, focusing on their established and potential clinical applications.

Clinical significance of genomic sequencing of circulating tumour cells (CTCs) in cancer

Circulating tumour cell (CTC), a rare subpopulations of tumour cells, plays a significant role in cancer metastasis and recurrence. The current review focuses on information of CTCs detection, enrichment, genome sequencing and investigating on clinical significance of CTCs sequencing in monitoring progress of patients with cancer. Tissue biopsy is not always favorable for monitoring cancer recurrence and metastases and can be difficult and risky for the patient's condition. On the other hand, enrichment and characterization of CTC could be effective in these circumstances. Accordingly, a number of detection (physical, immunological etc.), isolation (laser capture microdissection, DEPArray Di Electro phenetic array, fluorescence-activated cell sorting etc.) and enrichment platforms (Cellsearch, MagSwepeer, CTC-Chip etc.) have been developed. In addition, technologies for phenotypic characterization and genomic profiling (Tang's method, Smart-seq, Cel-seq etc.) at single-cell level has being established followed by genomic amplification. Importantly, numerous preclinical and clinical studies showed effective prognostic and predictive implications of molecular characterization of CTCs. CTC's sequencing has been successfully used as an effective tool to monitor genomic variations in the primary and metastatic tumours, thereby could predict the therapy resistance, recurrence of tumours. The genes expression profiles, stratification of cancers as well as identify the cancer cells with potential to undergo epithelial-mesenchymal transition (EMT) could also be identified. In addition, detection of mutational variants of CTCs by genome sequencing infer the therapeutic outcome and patient's survival. Therefore, CTC sequencing has potential to be used as a liquid biopsy tool for management of patients with cancers in clinical settings.

Dissemination of Circulating Tumor Cells in Breast and Prostate Cancer: Implications for Early Detection

Burgeoning evidence suggests that circulating tumor cells (CTCs) may disseminate into blood vessels at an early stage, seeding metastases in various cancers such as breast and prostate cancer. Simultaneously, the early-stage CTCs that settle in metastatic sites [termed disseminated tumor cells (DTCs)] can enter dormancy, marking a potential source of late recurrence and therapy resistance. Thus, the presence of these early CTCs poses risks to patients but also holds potential benefits for early detection and treatment and opportunities for possibly curative interventions. This review delves into the role of early DTCs in driving latent metastasis within breast and prostate cancer, emphasizing the importance of early CTC detection in these diseases. We further explore the correlation between early CTC detection and poor prognoses, which contribute significantly to increased cancer mortality. Consequently, the detection of CTCs at an early stage emerges as a critical imperative for enhancing clinical diagnostics and allowing for early interventions.

Circulating Tumor Cells: How Far Have We Come with Mining These Seeds of Metastasis?

Circulating tumor cells (CTCs) are cancer cells that slough off from the tumor and circulate in the peripheral blood and lymphatic system as micro metastases that eventually results in macro metastases. Through a simple blood draw, sensitive CTC detection from clinical samples has proven to be a useful tool for determining the prognosis of cancer. Recent technological developments now make it possible to detect CTCs reliably and repeatedly from a simple and straightforward blood test. Multicenter trials to assess the clinical value of CTCs have demonstrated the prognostic value of these cancer cells. Studies on CTCs have filled huge knowledge gap in understanding the process of metastasis since their identification in the late 19th century. However, these rare cancer cells have not been regularly used to tailor precision medicine and or identify novel druggable targets. In this review, we have attempted to summarize the milestones of CTC-based research from the time of identification to molecular characterization. Additionally, the need for a paradigm shift in dissecting these seeds of metastasis and the possible future avenues to improve CTC-based discoveries are also discussed.

Prognostic value of circulating tumor cells combined with neutrophil-lymphocyte ratio in patients with hepatocellular carcinoma

BACKGROUND

Circulating tumor cell (CTC) count and neutrophil-to-lymphocyte ratio (NLR) are both closely associated with the prognosis of hepatocellular carcinoma (HCC).

AIM

To investigate the prognostic value of combining these two indicators in HCC.

METHODS

Clinical data were collected from patients with advanced HCC who received immune therapy combined with targeted therapy at the Department of Oncology, the Affiliated Hospital of Southwest Medical University, Sichuan, China, from 2021 to 2023. The optimal cutoff values for CTC programmed death-ligand 1 (PD-L1) (+) > 1 or CTC PD-L1 (+) ≤ 1 and NLR > 3.89 or NLR ≤ 3.89 were evaluated using X-Tile software. Patients were categorized into three groups based on CTC PD-L1 (+) counts and NLR: CTC-NLR (0), CTC-NLR (1), and CTC-NLR (2). The relationship between CTC-NLR and clinical variables as well as survival rates was assessed.

RESULTS

Patients with high CTC PD-L1 (+) expression or NLR at baseline had shorter median progression-free survival (mPFS) and median overall survival (mOS) than those with low levels of CTC PD-L1 (+) or NLR (P < 0.001). Meanwhile, patients in the CTC-NLR (2) group showed a significant decrease in mPFS and mOS. Cox regression analysis revealed that alpha-fetoprotein (AFP), CTC PD-L1 (+), and CTC-NLR were independent predictors of OS. The time-dependent receiver operating characteristic curve showed that the area under the curve of CTC-NLR at 12 months (0.821) and 18 months (0.821) was superior to that of AFP and CTC PD-L1 (+).

CONCLUSION

HCC patients with high CTC PD-L1 (+) or NLR expression tend to exhibit poor prognosis, and a high baseline CTC-NLR score may indicate low survival. CTC-NLR may serve as an effective prognostic indicator for patients with advanced HCC receiving immunotherapy combined with targeted therapy.

New Breakthroughs in the Diagnosis of Leptomeningeal Carcinomatosis: A Review of Liquid Biopsies of Cerebrospinal Fluid

Leptomeningeal carcinomatosis represents a terminal stage and is a devastating complication of cancer. Despite its high incidence, current diagnostic methods fail to accurately detect this condition in a timely manner. This failure to diagnose leads to the refusal of treatment and the absence of clinical trials, hampering the development of new therapy strategies. The use of liquid biopsy is revolutionizing the field of diagnostic oncology. The dynamic and non-invasive detection of tumor markers has enormous potential in cancer diagnostics and treatment. Leptomeningeal carcinomatosis is a condition where invasive tissue biopsy is not part of the routine diagnostic analysis, making liquid biopsy an essential diagnostic tool. Several elements in cerebrospinal fluid (CSF) have been investigated as potential targets of liquid biopsy, including free circulating tumor cells, free circulating nucleic acids, proteins, exosomes, and even non-tumor cells as part of the dynamic tumor microenvironment. This review aims to summarize current breakthroughs in the research on liquid biopsy, including the latest breakthroughs in the identification of tumor cells and nucleic acids, and give an overview of future directions in the diagnosis of leptomeningeal carcinomatosis.

Circulating and Imaging Biomarkers of Radium-223 Response in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Radium-223 improves overall survival (OS) and reduces skeletal events in patients with bone metastatic castration-resistant prostate cancer (CRPC), but relevant biomarkers are lacking. We evaluated automated bone scan index (aBSI) and circulating tumor cell (CTC) analyses as potential biomarkers of prognosis and activity.

PATIENTS AND METHODS

Patients with bone metastatic CRPC were enrolled on a prospective single-arm study of standard radium-223. 99mTc-MDP bone scan images at baseline, 2 months, and 6 months were quantitated using aBSI. CTCs at baseline, 1 month, and 2 months were enumerated and assessed for RNA expression of prostate cancer-specific genes using microfluidic enrichment followed by droplet digital polymerase chain reaction.

RESULTS

The median OS was 21.3 months in 22 patients. Lower baseline aBSI and minimal change in aBSI (<+0.7) from baseline to 2 months were each associated with better OS (P = .00341 and P = .0139, respectively). The higher baseline CTC count of ≥5 CTC/7.5 mL was associated with worse OS (median, 10.1 v 32.9 months; P = .00568). CTCs declined at 2 months in four of 15 patients with detectable baseline CTCs. Among individual genes in CTCs, baseline expression of the splice variant AR-V7 was significantly associated with worse OS (hazard ratio, 5.20 [95% CI, 1.657 to 16.31]; P = .00195). Baseline detectable AR-V7, higher aBSI, and CTC count ≥5 CTC/7.5 mL continued to have a significant independent negative impact on OS after controlling for prostate-specific antigen or alkaline phosphatase.

CONCLUSION

Quantitative bone scan assessment with aBSI and CTC analyses are prognostic markers in patients treated with radium-223. AR-V7 expression in CTCs is a particularly promising prognostic biomarker and warrants validation in larger cohorts.

Research progress of CTC, ctDNA, and EVs in cancer liquid biopsy

Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vehicles (EVs) have received significant attention in recent times as emerging biomarkers and subjects of transformational studies. The three main branches of liquid biopsy have evolved from the three primary tumor liquid biopsy detection targets-CTC, ctDNA, and EVs-each with distinct benefits. CTCs are derived from circulating cancer cells from the original tumor or metastases and may display global features of the tumor. ctDNA has been extensively analyzed and has been used to aid in the diagnosis, treatment, and prognosis of neoplastic diseases. EVs contain tumor-derived material such as DNA, RNA, proteins, lipids, sugar structures, and metabolites. The three provide different detection contents but have strong complementarity to a certain extent. Even though they have already been employed in several clinical trials, the clinical utility of three biomarkers is still being studied, with promising initial findings. This review thoroughly overviews established and emerging technologies for the isolation, characterization, and content detection of CTC, ctDNA, and EVs. Also discussed were the most recent developments in the study of potential liquid biopsy biomarkers for cancer diagnosis, therapeutic monitoring, and prognosis prediction. These included CTC, ctDNA, and EVs. Finally, the potential and challenges of employing liquid biopsy based on CTC, ctDNA, and EVs for precision medicine were evaluated.

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.

Circulating Tumor Cells are an Independent Risk Factor for Poor Prognosis in Patients with Gallbladder Adenocarcinoma

BACKGROUND

The study aimed to evaluate the prognostic impact of circulating tumor cells (CTCs) in patients with gallbladder adenocarcinoma after resection.

MATERIALS AND METHODS

Between January 2018 and January 2021, 101 consecutive patients with gallbladder adenocarcinoma were included. CTCs were detected and enumerated using the CanPatrol® technique. The follow-up period ended in January 2023. The cancer-specific survival (CSS) and disease-free survival (DFS) were calculated using log-rank and Cox regression analyses.

RESULTS

CTCs were detected positively in 61.54% (8/13) of the patients in the non-operation group and 13.64% (12/88) in the operation group. In the operation group, the median CSS for CTCs-positive and CTCs-negative patients was 5.0 and 9.5 months (P < 0.001), respectively, and DFS was 2.8 and 5.0 months at stage III (P < 0.001), respectively. In the non-operation group, the median CSS for CTCs-positive and CTCs-negative patients was 3.5 and 6.5 months (P = 0.0031), respectively. The median CSS for CTCs-positive patients in the operation group was similar to that in the non-operation group (P = 0.67). Multivariate analyses showed that positive CTCs was an independent risk factor for poor CSS (HR 0.066, 95% CI 0.021-0.206, P < 0.001) as well as lymph infiltration (HR 0.320, 95% CI 0.110-0.930, P = 0.036), without R0 curative resection (HR 7.520, 95% CI 2.100-26.931, P = 0.002), and without adjuvant chemotherapy (HR 7.730, 95% CI 2.416-24.731, P < 0.001).

CONCLUSION

Positive CTCs was an independent predictor of poor prognosis after resection in patients with gallbladder adenocarcinoma. Preoperative detection of CTCs may play an important guiding role in formulating treatment strategies for these patients.

Evolving insights in blood-based liquid biopsies for prostate cancer interrogation

During the last decade, blood sampling of cancer patients aimed at analyzing the presence of cells, membrane-bound vesicles, or molecules released by primary tumors or metastatic growths emerged as an alternative to traditional tissue biopsies. The advent of this minimally invasive approach, known as blood-based liquid biopsy, began to play a pivotal role in the management of diverse cancers, establishing itself as a vital component of precision medicine. Here, we discuss three blood-based liquid biopsies, namely circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and tumor-derived exosomes, as they relate to prostate cancer (PCa) management. The advances achieved in the molecular characterization of these types of liquid biopsies and their potential to predict recurrence, improve responses to certain treatments, and evaluate prognosis, in PCa patients, are highlighted herein. While there is currently full clinical validation for only one CTC-based and one ctDNA-based liquid biopsy for patients with metastatic castration-resistant PCa, the adoption of additional methods is anticipated as they undergo standardization and achieve analytical and clinical validation. Advantages and disadvantages of different blood-based liquid biopsy approaches in the context of PCa are outlined herein, while also considering potential synergies through combinatory strategies.

Mitochondrially targeted tamoxifen as anticancer therapy: case series of patients with renal cell carcinoma treated in a phase I/Ib clinical trial

Mitochondrially targeted anticancer drugs (mitocans) that disrupt the energy-producing systems of cancer are emerging as new potential therapeutics. Mitochondrially targeted tamoxifen (MitoTam), an inhibitor of mitochondrial respiration respiratory complex I, is a first-in-class mitocan that was tested in the phase I/Ib MitoTam-01 trial of patients with metastatic cancer. MitoTam exhibited a manageable safety profile and efficacy; among 37% (14/38) of responders, the efficacy was greatest in patients with metastatic renal cell carcinoma (RCC) with a clinical benefit rate of 83% (5/6) of patients. This can be explained by the preferential accumulation of MitoTam in the kidney tissue in preclinical studies. Here we report the mechanism of action and safety profile of MitoTam in a case series of RCC patients. All six patients were males with a median age of 69 years, who had previously received at least three lines of palliative systemic therapy and suffered progressive disease before starting MitoTam. We recorded stable disease in four, partial response in one, and progressive disease (PD) in one patient. The histological subtype matched clear cell RCC (ccRCC) in the five responders and claro-cellular carcinoma with sarcomatoid features in the non-responder. The number of circulating tumor cells (CTCs) was evaluated longitudinally to monitor disease dynamics. Beside the decreased number of CTCs after MitoTam administration, we observed a significant decrease of the mitochondrial network mass in enriched CTCs. Two patients had long-term clinical responses to MitoTam, of 50 and 36 weeks. Both patients discontinued treatment due to adverse events, not PD. Two patients who completed the trial in November 2019 and May 2020 are still alive without subsequent anticancer therapy. The toxicity of MitoTam increased with the dosage but was manageable. The efficacy of MitoTam in pretreated ccRCC patients is linked to the novel mechanism of action of this first-in-class mitochondrially targeted drug.

Circulating Tumor Cells Adhesion: Application in Biosensors

The early and non-invasive diagnosis of tumor diseases has been widely investigated by the scientific community focusing on the development of sensors/biomarkers that act as a way of recognizing the adhesion of circulating tumor cells (CTCs). As a challenge in this area, strategies for CTCs capture and enrichment currently require improvements in the sensors/biomarker's selectivity. This can be achieved by understanding the biological recognition factors for different cancer cell lines and also by understanding the interaction between surface parameters and the affinity between macromolecules and the cell surface. To overcome some of these concerns, electrochemical sensors have been used as precise, fast-response, and low-cost transduction platforms for application in cytosensors. Additionally, distinct materials, geometries, and technologies have been investigated to improve the sensitivity and specificity properties of the support electrode that will transform biochemical events into electrical signals. This review identifies novel approaches regarding the application of different specific biomarkers (CD44, Integrins, and EpCAm) for capturing CTCs. These biomarkers can be applied in electrochemical biosensors as a cytodetection strategy for diagnosis of cancerous diseases.

mFast-SeqS-based aneuploidy score in circulating cell-free DNA is a prognostic biomarker in prostate cancer

Multiple prognostic biomarkers, including circulating tumour cell (CTC) counts, exist in metastatic castration-resistant prostate cancer (mCRPC) patients, but none of them have been implemented into daily clinical care. The modified fast aneuploidy screening test-sequencing system (mFast-SeqS), which yields a genome-wide aneuploidy score, is able to reflect the fraction of cell-free tumour DNA (ctDNA) within cell-free DNA (cfDNA) and may be a promising biomarker in mCRPC. In this study, we investigated the prognostic value of dichotomized aneuploidy scores (< 5 vs. ≥ 5) as well as CTC counts (< 5 vs. ≥ 5) in 131 mCRPC patients prior to treatment with cabazitaxel. We validated our findings in an independent cohort of 50 similarly treated mCRPC patients. We observed that, similar to the dichotomized CTC count [HR: 2.92; 95% confidence interval (CI);1.84-4.62], dichotomized aneuploidy scores (HR: 3.24; CI: 2.12-4.94) significantly correlated with overall survival in mCRPC patients. We conclude that a dichotomized aneuploidy score from cfDNA is a prognostic marker for survival in mCRPC patients within our discovery cohort and in an independent mCRPC validation cohort. Therefore, this easy and robust minimally-invasive assay can be readily implemented as a prognostic marker in mCRPC. A dichotomized aneuploidy score might also be used as a stratification factor in clinical studies to account for tumour load.

The Emerging Role of Liquid Biopsies in Revolutionising Cancer Diagnosis and Therapy

A potential non-invasive technique for identifying and tracking cancer is a liquid biopsy. This review article provides a comprehensive overview of the principles, applications, and challenges associated with liquid biopsies. The circulating tumour DNA (ctDNA), circulating tumour cells (CTCs), exosomes, and microRNAs are just a few of the biomarkers we cover in this article that are discovered in liquid biopsies. The clinical application of liquid biopsies in many stages of cancer management, including early cancer identification, therapy selection and response monitoring, and minimum residual illness, is also investigated. The technical advancements in liquid biopsy techniques, including digital polymerase chain reaction (dPCR) and next-generation sequencing (NGS), have improved the sensitivity and specificity of biomarker identification. Liquid biopsies require assistance with cost-effectiveness, sensitivity, and standardisation despite the potential benefits. We talk about these restrictions and potential solutions. In conclusion, liquid biopsies revolutionise personalised therapies and cancer diagnostics by providing a real-time, non-invasive tool for characterising and monitoring tumours. It will be possible to expand the use of liquid biopsies in clinical practises by having a better understanding of their current state and predicted future developments.

Cancer Associated Macrophage-like Cells Are Prognostic for Highly Aggressive Prostate Cancer in Both the Non-Metastatic and Metastatic Settings

Despite advancements in the early-stage detection and expansion of treatments for prostate cancer (PCa), patient mortality rates remain high in patients with aggressive disease and the overtreatment of indolent disease remains a major issue. Prostate-specific antigen (PSA), a standard PCa blood biomarker, is limited in its ability to differentiate disease subtypes resulting in the overtreatment of non-aggressive indolent disease. Here we assess engorged cancer-associated macrophage-like cells (CAMLs), a ≥50 µm, cancer-specific, polynucleated circulating cell type found in the blood of patients with PCa as a potential companion biomarker to PSA for patient risk stratification. We found that rising PSA is positively correlated with increasing CAML size (r = 0.307, p = 0.004) and number of CAMLs in circulation (r = 0.399, p < 0.001). Over a 2-year period, the presence of a single engorged CAML was associated with 20.9 times increased likelihood of progression (p = 0.016) in non-metastatic PCa, and 2.4 times likelihood of progression (p = 0.031) with 5.4 times likelihood of death (p < 0.001) in metastatic PCa. These preliminary data suggest that CAML cell monitoring, in combination with PSA, may aid in differentiating non-aggressive from aggressive PCas by adding biological information that complements traditional clinical biomarkers, thereby helping guide treatment strategies.

Genetic and epigenetic features of neuroendocrine prostate cancer and their emerging applications

Prostate cancer is the second most prevalent cancer in men globally. De novo neuroendocrine prostate cancer (NEPC) is uncommon at initial diagnosis, however, (treatment-induced) t-NEPC emerges in up to 25% of prostate adenocarcinoma (PRAD) cases treated with androgen deprivation, carrying a drastically poor prognosis. The transition from PRAD to t-NEPC is underpinned by several key genetic mutations; TP53, RB1, and MYCN are the main genes implicated, bearing similarities to other neuroendocrine tumours. A broad range of epigenetic alterations, such as aberrations in DNA methylation, histone post-translational modifications, and non-coding RNAs, may drive lineage plasticity from PRAD to t-NEPC. The clinical diagnosis of NEPC is hampered by a lack of accessible biomarkers; recent advances in liquid biopsy techniques assessing circulating tumour cells and ctDNA in NEPC suggest that the advent of non-invasive means of monitoring progression to NEPC is on the horizon. Such techniques are vital for NEPC management; diagnosis of t-NEPC is crucial for implementing effective treatment, and precision medicine will be integral to providing the best outcomes for patients.

Circulating tumour cells for early detection of clinically relevant cancer

Given that cancer mortality is usually a result of late diagnosis, efforts in the field of early detection are paramount to reducing cancer-related deaths and improving patient outcomes. Increasing evidence indicates that metastasis is an early event in patients with aggressive cancers, often occurring even before primary lesions are clinically detectable. Metastases are usually formed from cancer cells that spread to distant non-malignant tissues via the blood circulation, termed circulating tumour cells (CTCs). CTCs have been detected in patients with early stage cancers and, owing to their association with metastasis, might indicate the presence of aggressive disease, thus providing a possible means to expedite diagnosis and treatment initiation for such patients while avoiding overdiagnosis and overtreatment of those with slow-growing, indolent tumours. The utility of CTCs as an early diagnostic tool has been investigated, although further improvements in the efficiency of CTC detection are required. In this Perspective, we discuss the clinical significance of early haematogenous dissemination of cancer cells, the potential of CTCs to facilitate early detection of clinically relevant cancers, and the technological advances that might improve CTC capture and, thus, diagnostic performance in this setting.

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.

PSMA-heterogeneity in metastatic castration-resistant prostate cancer: Circulating tumor cells, metastatic tumor burden, and response to targeted radioligand therapy

BACKGROUND

We explored the interrelation between prostate-specific membrane antigen (PSMA) expression on circulating tumor cells (CTCs) and that of solid metastatic lesions as determined by whole-body PSMA-targeted positron emission tomography (PET) to refine the prediction of response to subsequent PSMA-targeted radioligand therapy (RLT).

METHODS

A prospective study was performed in 20 patients with advanced mCRPC. Of these, 16 underwent subsequent RLT with [¹⁷⁷ Lu]Lu-PSMA-617 at a dose of 7.4 GBq every 6-8 weeks. PSMA expression on CTCs using the CellSearch system was compared to clinical and serological results, and to marker expression in targeted imaging and available histological sections of prostatectomy specimens (19% of RLT patients). Clinical outcome was obtained after two cycles of RLT.

RESULTS

Marked heterogeneity of PSMA expression was observed already at first diagnosis in available histological specimens. Targeted whole-body imaging also showed heterogeneous inter- and intra-patient PSMA expression between metastases. Heterogeneity of CTC PSMA expression was partially paralleled by heterogeneity of whole-body tumor burden PSMA expression. Twenty percent of CTC samples showed no PSMA expression, despite unequivocal PSMA expression of solid metastases at PET. A high fraction of PSMA-negative CTCs emerged as the sole predictor of poor RLT response (odds ratio [OR]: 0.9379 [95% confidence interval, CI, 0.8558-0.9902]; p = 0.0160), and was prognostic for both shorter progression-free survival (OR: 1.236 [95% CI, 1.035-2.587]; p = 0.0043) and overall survival (OR: 1.056 [95% CI, 1.008-1.141]; p = 0.0182).

CONCLUSION

This proof-of-principle study suggests that liquid biopsy for CTC PSMA expression is complementary to PET for individual PSMA phenotyping of mCRPC.

Baseline CTC Count as a Predictor of Long-Term Outcomes in High-Risk Prostate Cancer

The aim of the present study was to verify whether the baseline circulating tumor cell (CTC) count might serve as a predictor of overall survival (OS) and metastasis-free survival (MFS) in patients with high-risk prostate cancer (PCa) during a follow-up period of at least 5 years. CTCs were enumerated using three different assay formats in 104 patients: the CellSearch® system, EPISPOT assay and GILUPI CellCollector. A total of 57 (55%) patients survived until the end of the follow-up period, with a 5 year OS of 66% (95% CI: 56–74%). The analysis of univariate Cox proportional hazard models identified a baseline CTC count ≥ 1, which was determined with the CellSearch® system, a Gleason sum ≥ 8, cT ≥ 2c and metastases at initial diagnosis as significant predictors of a worse OS in the entire cohort. The CTC count ≥ 1 was also the only significant predictor of a worse OS in a subset of 85 patients who presented with localized PCa at the baseline. The baseline CTC number did not affect the MFS. In conclusion, the baseline CTC count can be considered a determinant of survival in high-risk PCa and also in patients with a localized disease. However, determining the prognostic value of the CTC count in patients with localized PCa would optimally require longitudinal monitoring of this parameter.

A correlative biomarker study and integrative prognostic model in chemotherapy-naïve metastatic castration-resistant prostate cancer treated with enzalutamide

BACKGROUND

There is a considerable need to incorporate biomarkers of resistance to new antiandrogen agents in the management of castration-resistant prostate cancer (CRPC).

METHODS

We conducted a phase II trial of enzalutamide in first-line chemo-naïve asymptomatic or minimally symptomatic mCRPC and analyzed the prognostic value of TMPRSS2-ERG and other biomarkers, including circulating tumor cells (CTCs), androgen receptor splice variant (AR-V7) in CTCs and plasma Androgen Receptor copy number gain (AR-gain). These biomarkers were correlated with treatment response and survival outcomes and developed a clinical-molecular prognostic model using penalized cox-proportional hazard model. This model was validated in an independent cohort.

RESULTS

Ninety-eight patients were included. TMPRSS2-ERG fusion gene was detected in 32 patients with no differences observed in efficacy outcomes. CTC detection was associated with worse outcome and AR-V7 in CTCs was associated with increased rate of progression as best response. Plasma AR gain was strongly associated with an adverse outcome, with worse median prostate specific antigen (PSA)-PFS (4.2 vs. 14.7 m; p < 0.0001), rad-PFS (4.5 vs. 27.6 m; p < 0.0001), and OS (12.7 vs. 38.1 m; p < 0.0001). The clinical prognostic model developed in PREVAIL was validated (C-Index 0.70) and the addition of plasma AR (C-Index 0.79; p < 0.001) increased its prognostic ability. We generated a parsimonious model including alkaline phosphatase (ALP); PSA and AR gain (C-index 0.78) that was validated in an independent cohort.

CONCLUSIONS

TMPRSS2-ERG detection did not correlate with differential activity of enzalutamide in first-line mCRPC. However, we observed that CTCs and plasma AR gain were the most relevant biomarkers.

Biology, vulnerabilities and clinical applications of circulating tumour cells

In recent years, exceptional technological advances have enabled the identification and interrogation of rare circulating tumour cells (CTCs) from blood samples of patients, leading to new fields of research and fostering the promise for paradigm-changing, liquid biopsy-based clinical applications. Analysis of CTCs has revealed distinct biological phenotypes, including the presence of CTC clusters and the interaction between CTCs and immune or stromal cells, impacting metastasis formation and providing new insights into cancer vulnerabilities. Here we review the progress made in understanding biological features of CTCs and provide insight into exploiting these developments to design future clinical tools for improving the diagnosis and treatment of cancer.

Folate receptor-positive circulating tumor cell count, lymphocyte count and derived neutrophil-to- lymphocyte ratio for diagnosing lung cancer relapse

The folate receptor-positive circulating tumor cell (FR⁺-CTC) count can be used to improve the diagnosis rate of lung cancer. The lymphocyte count (LC) and derived neutrophil-to-lymphocyte ratio (dNLR) are involved in inflammatory processes. Whether the FR⁺-CTC count combined with the dNLR or LC is helpful for diagnosing lung cancer recurrence is not clear. Sixty-eight patients who were initially diagnosed with lung cancer and received first-line treatment were included. The clinicopathological characteristics, routine blood examination results and CTC examination results of the patients were collected. The role of the complete blood count and FR⁺-CTC count in lung cancer treatment response and prognosis was analyzed. The FR⁺-CTC count after treatment was significantly correlated with the T stage (p=0.005). Multivariate analysis showed that the pathological type and FR⁺-CTC count were independent predictors of disease-or progression-free survival (DFS/PFS) in patients with lung cancer (p=0.010 and p=0.030, respectively). The FR⁺-CTC count, LC and dNLR predicted the recurrence of lung cancer (sensitivity and specificity of the FR⁺-CTC count, 69.2% and 71.4%; the LC, 50.0% and 88.5%; and the dNLR, 50.0% and 88.1%, respectively). The FR⁺-CTC count combined with the LC or dNLR improved the diagnostic rate of lung cancer recurrence (sensitivity and specificity of the FR⁺-CTC count plus the LC, 53.8% and 90.5%, and the FR⁺-CTC count plus the dNLR, 73.1% and 73.8%, respectively). When these three indicators were combined to predict lung cancer recurrence, the AUC value was 0.817. The FR⁺-CTC count combined with the dNLR and/or LC after treatment can improve the diagnostic rate of lung cancer recurrence. A higher FR⁺-CTC count predicts worse DFS/PFS in patients with lung cancer.

The potential of using circulating tumour cells and their gene expression to predict docetaxel response in metastatic prostate cancer

Background

Docetaxel improves overall survival (OS) in castration-resistant prostate cancer (PCa) (CRPC) and metastatic hormone-sensitive PCa (mHSPC). However, not all patients respond due to inherent and/or acquired resistance. There remains an unmet clinical need for a robust predictive test to stratify patients for treatment. Liquid biopsy of circulating tumour cell (CTCs) is minimally invasive, can provide real-time information of the heterogeneous tumour and therefore may be a potentially ideal docetaxel response prediction biomarker.

Objective

In this study we investigate the potential of using CTCs and their gene expression to predict post-docetaxel tumour response, OS and progression free survival (PFS).

Methods

Peripheral blood was sampled from 18 mCRPC and 43 mHSPC patients, pre-docetaxel treatment, for CTC investigation. CTCs were isolated using the epitope independent Parsortix^® system and gene expression was determined by multiplex RT-qPCR. We evaluated CTC measurements for post-docetaxel outcome prediction using receiver operating characteristics and Kaplan Meier analysis.

Results

Detection of CTCs pre-docetaxel was associated with poor patient outcome post-docetaxel treatment. Combining total-CTC number with PSA and ALP predicted lack of partial response (PR) with an AUC of 0.90, p= 0.037 in mCRPC. A significantly shorter median OS was seen in mCRPC patients with positive CTC-score (12.80 vs. 37.33 months, HR= 5.08, p= 0.0005), ≥3 total-CTCs/7.5mL (12.80 vs. 37.33 months, HR= 3.84, p= 0.0053), ≥1 epithelial-CTCs/7.5mL (14.30 vs. 37.33 months, HR= 3.89, p= 0.0041) or epithelial to mesenchymal transitioning (EMTing)-CTCs/7.5mL (11.32 vs. 32.37 months, HR= 6.73, p= 0.0001). Significantly shorter PFS was observed in patients with ≥2 epithelial-CTCs/7.5mL (7.52 vs. 18.83 months, HR= 3.93, p= 0.0058). mHSPC patients with ≥5 CTCs/7.5mL had significantly shorter median OS (24.57 vs undefined months, HR= 4.14, p= 0.0097). In mHSPC patients, expression of KLK2, KLK4, ADAMTS1, ZEB1 and SNAI1 was significantly associated with shorter OS and/or PFS. Importantly, combining CTC measurements with clinical biomarkers increased sensitivity and specificity for prediction of patient outcome.

Conclusion

While it is clear that CTC numbers and gene expression were prognostic for PCa post-docetaxel treatment, and CTC subtype analysis may have additional value, their potential predictive value for docetaxel chemotherapy response needs to be further investigated in large patient cohorts.

Detection of Circulating Tumor Cells Using the Attune NxT

Circulating tumor cells (CTCs) have been detected in many patients with different solid malignancies. It has been reported that presence of CTCs correlates with worse survival in patients with multiple types of cancer. Several techniques have been developed to detect CTCs in liquid biopsies. Currently, the only method for CTC detection that is approved by the Food and Drug Administration is CellSearch. Due to low abundance of CTCs in certain cancer types and in early stages of disease, its clinical application is currently limited to metastatic colorectal cancer, breast cancer and prostate cancer. Therefore, we aimed to develop a new method for the detection of CTCs using the Attune NxT-a flow cytometry-based application that was specifically developed to detect rare events in biological samples without the need for enrichment. When healthy donor blood samples were spiked with variable amounts of different EpCAM+EGFR+ tumor cell lines, recovery yield was on average 75%. The detection range was between 1000 and 10 cells per sample. Cell morphology was confirmed with the Attune CytPix. Analysis of blood samples from metastatic colorectal cancer patients, as well as lung cancer patients, demonstrated that increased EpCAM+EGFR+ events were detected in more than half of the patient samples. However, most of these cells showed no (tumor) cell-like morphology. Notably, CellSearch analysis of blood samples from a subset of colorectal cancer patients did not detect CTCs either, suggesting that these blood samples were negative for CTCs. Therefore, we anticipate that the Attune NxT is not superior to CellSearch in detection of low amounts of CTCs, although handling and analysis of samples is easier. Moreover, morphological confirmation is essential to distinguish between CTCs and false positive events.

Circulating tumour cells in patients with lung cancer universally indicate poor prognosis

BACKGROUND

In lung cancer, the relevance of various circulating tumour cell (CTC) subgroups in different lung cancer subtypes is unclear. We performed a comprehensive meta-analysis to assess the prognostic value of CTCs in the different histological types of lung cancer, with particular respect to CTC subtypes, cut-offs and time points of CTC enumeration.

METHODS

We searched MEDLINE, Web of Science and Embase alongside relevant studies evaluating the prognostic value of CTCs in lung cancer patients. A random-effects model was used for meta-analysis, calculating hazard ratios (HRs), 95% confidence intervals and p-values.

RESULTS

27 studies enrolling 2957 patients were included. CTC detection indicates poor prognosis, especially in small cell lung cancer (SCLC) patients (overall survival HR 3.11, 95% CI 2.59-3.73) and predicts a worse outcome compared to nonsmall cell lung cancer patients. Epithelial CTCs predict a worse outcome for lung cancer than mesenchymal CTCs or epithelial-mesenchymal hybrids.

CONCLUSION

CTCs indicate poor prognosis in patients with primary lung cancer, with CTCs in SCLC having a more pronounced prognostic effect. The prognostic value of CTCs detected by different markers varies; most evidence is available for the strong negative prognostic effect of epithelial CTCs.

Recent advances in micro-/nanostructure array integrated microfluidic devices for efficient separation of circulating tumor cells

Circulating tumor cells (CTCs) released from the primary tumor to peripheral blood are promising targets for liquid biopsies. Their biological information is vital for early cancer detection, efficacy assessment, and prognostic monitoring. Despite the tremendous clinical applications of CTCs, development of effective separation techniques are still demanding. Traditional separation methods usually use batch processing for enrichment, which inevitably destroy cell integrity and affect the complete information acquisition. Considering the rarity and heterogeneity of CTCs, it is urgent to develop effective separation methods. Microfluidic chips with precise fluid control at the micron level are promising devices for CTC separation. Their further combination with micro-/nanostructure arrays adds more biomolecule binding sites and exhibit unique fluid barrier effect, which significantly improve the CTC capture efficiency, purity, and sensitivity. This review summarized the recent advances in micro-/nanostructure array integrated microfluidic devices for CTC separation, including microrods, nanowires, and 3D micro-/nanostructures. The mechanisms by which these structures contribute to improved capture efficiency are discussed. Two major categories of separation methods, based on the physical and biological properties of CTCs, are discussed separately. Physical separation includes the design and preparation of micro-/nanostructure arrays, while chemical separation additionally involves the selection and modification of specific capture probes. These emerging technologies are expected to become powerful tools for disease diagnosis in the future.

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.

Plasma Copy Number Alteration-Based Prognostic and Predictive Multi-Gene Risk Score in Metastatic Castration-Resistant Prostate Cancer

Prostate cancer (PCa) accounted for more than 34,000 deaths in US males [...].

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

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.

Overcoming Obstacles in Liquid Biopsy Developments for Prostate Cancer

Prostate cancer is one of the most common malignancies in men. Over time, it can metastasize and become lethal once it exhausts hormonal therapies and transitions into castration-resistant prostate cancer (CRPC). Several therapies have been recently approved for advanced prostate cancer, but identifying biomarkers for current treatments and searching for more effective treatments are urgently needed. Liquid biopsy is a powerful tool for isolating genetic material, proteins, and whole tumor cells from the blood. In recent decades, this technology has rapidly advanced, allowing for better insights into the pathogenesis and treatment response in different stages of prostate cancer. In this review, we summarize important clinical studies involving liquid biopsies in prostate cancer with a focus on advanced disease, notably regarding circulating tumor DNA, circulating tumor cells, and exosomes. We highlight the progress and the challenges that still exist for these technologies. Finally, we discuss promising avenues that will further expand the importance of liquid biopsy in the care for prostate cancer patients.

Biomarkers in Urological Cancers

Urological tumours have become one of the most common cancers in the last decade. It is important to apply an approach that evaluates many factors related to the patient and the disease carefully to minimize cancer-associated morbidity and mortality. The clinical use of cancer biomarkers is a valuable part of the clinical management of urological cancers. These biomarkers may lead to optimized detection, treatment, and follow-up of urological cancers. With the development of molecular research, newly developed biomarkers and next-generation sequencing have also contributed to patient management. In this chapter, we will present biomarkers in the most common urological cancers under subheadings of bladder cancer, prostate cancer, kidney cancer, and testicular cancer. Additionally, due to the development that occurred in the next-generation sequencing (NGS), all the above-mentioned malignancies are evaluated with regard to NGS.

Circulating Cells with Macrophage-like Characteristics in Cancer: The Importance of Circulating Neoplastic-Immune Hybrid Cells in Cancer

Simple Summary

In cancer, disseminated neoplastic cells circulating in blood are a source of tumor DNA, RNA, and protein, which can be harnessed to diagnose, monitor, and better understand the biology of the tumor from which they are derived. Historically, circulating tumor cells (CTCs) have dominated this field of study. While CTCs are shed directly into circulation from a primary tumor, they remain relatively rare, particularly in early stages of disease, and thus are difficult to utilize as a reliable cancer biomarker. Neoplastic-immune hybrid cells represent a novel subpopulation of circulating cells that are more reliably attainable as compared to their CTC counterparts. Here, we review two recently identified circulating cell populations in cancer—cancer-associated macrophage-like cells and circulating hybrid cells—and discuss the future impact for the exciting area of disseminated hybrid cells.

Abstract

Cancer remains a significant cause of mortality in developed countries, due in part to difficulties in early detection, understanding disease biology, and assessing treatment response. If effectively harnessed, circulating biomarkers promise to fulfill these needs through non-invasive “liquid” biopsy. While tumors disseminate genetic material and cellular debris into circulation, identifying clinically relevant information from these analytes has proven difficult. In contrast, cell-based circulating biomarkers have multiple advantages, including a source for tumor DNA and protein, and as a cellular reflection of the evolving tumor. While circulating tumor cells (CTCs) have dominated the circulating cell biomarker field, their clinical utility beyond that of prognostication has remained elusive, due to their rarity. Recently, two novel populations of circulating tumor-immune hybrid cells in cancer have been characterized: cancer-associated macrophage-like cells (CAMLs) and circulating hybrid cells (CHCs). CAMLs are macrophage-like cells containing phagocytosed tumor material, while CHCs can result from cell fusion between cancer and immune cells and play a role in the metastatic cascade. Both are detected in higher numbers than CTCs in peripheral blood and demonstrate utility in prognostication and assessing treatment response. Additionally, both cell populations are heterogeneous in their genetic, transcriptomic, and proteomic signatures, and thus have the potential to inform on heterogeneity within tumors. Herein, we review the advances in this exciting field.