Circulating tumor cells: biology and clinical significance

Preclinical models to study patient-derived circulating tumor cells and metastasis

Circulating tumor cells (CTCs) that are detached from the tumor can be precursors of metastasis. The majority of studies focus on enumeration of CTCs from patient blood to predict recurrence and therapy outcomes. Very few studies have managed to expand CTCs to investigate their functional dynamics with respect to genetic changes, tumorigenic potential, and response to drug treatment. A growing amount of evidence based on successful CTC expansion has revealed novel therapeutic targets that are associated with the process of metastasis. In this review, we summarize the successes, challenges, and limitations that collectively contribute to the better understanding of metastasis using patient-derived CTCs as blood-borne seeds of metastasis. The roadblocks and future avenues to move CTC-based scientific discoveries forward are also discussed.

Optical Detection of Cancer Cells Using Lab-on-a-Chip

The global need for accurate and efficient cancer cell detection in biomedicine and clinical diagnosis has driven extensive research and technological development in the field. Precision, high-throughput, non-invasive separation, detection, and classification of individual cells are critical requirements for successful technology. Lab-on-a-chip devices offer enormous potential for solving biological and medical problems and have become a priority research area for microanalysis and manipulating cells. This paper reviews recent developments in the detection of cancer cells using the microfluidics-based lab-on-a-chip method, focusing on describing and explaining techniques that use optical phenomena and a plethora of probes for sensing, amplification, and immobilization. The paper describes how optics are applied in each experimental method, highlighting their advantages and disadvantages. The discussion includes a summary of current challenges and prospects for cancer diagnosis.

Deciphering epithelial-to-mesenchymal transition in pancreatic cancer

Epithelial to mesenchymal transition (EMT) is a complex cellular program that alters epithelial cells and induces their transformation into mesenchymal cells. While essential to normal developmental processes such as embryogenesis and wound healing, EMT has also been linked to the development and progression of various diseases, including fibrogenesis and tumorigenesis. Under homeostatic conditions, initiation of EMT is mediated by key signaling pathways and pro-EMT-transcription factors (EMT-TFs); however, in certain contexts, these pro-EMT regulators and programs also drive cell plasticity and cell stemness to promote oncogenesis as well as metastasis. In this review, we will explain how EMT and EMT-TFs mediate the initiation of pro-cancer states and how they influence late-stage progression and metastasis in pancreatic ductal adenocarcinoma (PDAC), the most severe form of pancreatic cancer.

Targeting Mitochondria with ClpP Agonists as a Novel Therapeutic Opportunity in Breast Cancer

Breast cancer is the most frequently diagnosed malignancy worldwide and the leading cause of cancer mortality in women. Despite the recent development of new therapeutics including targeted therapies and immunotherapy, triple-negative breast cancer remains an aggressive form of breast cancer, and thus improved treatments are needed. In recent decades, it has become increasingly clear that breast cancers harbor metabolic plasticity that is controlled by mitochondria. A myriad of studies provide evidence that mitochondria are essential to breast cancer progression. Mitochondria in breast cancers are widely reprogrammed to enhance energy production and biosynthesis of macromolecules required for tumor growth. In this review, we will discuss the current understanding of mitochondrial roles in breast cancers and elucidate why mitochondria are a rational therapeutic target. We will then outline the status of the use of mitochondria-targeting drugs in breast cancers, and highlight ClpP agonists as emerging mitochondria-targeting drugs with a unique mechanism of action. We also illustrate possible drug combination strategies and challenges in the future breast cancer clinic.

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

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

Circulating tumour cells in gastrointestinal cancers: food for thought?

Gastrointestinal (GI) cancers account for 35% of cancer-related deaths, predominantly due to their ability to spread and generate drug-tolerant metastases. Arising from different locations in the GI system, the majority of metastatic GI malignancies colonise the liver and the lungs. In this context, circulating tumour cells (CTCs) are playing a critical role in the formation of new metastases, and their presence in the blood of patients has been correlated with a poor outcome. In addition to their prognostic utility, prospective targeting of CTCs may represent a novel, yet ambitious strategy in the fight against metastasis. A better understanding of CTC biology, mechanistic underpinnings and weaknesses may facilitate the development of previously underappreciated anti-metastasis approaches. Here, along with related clinical studies, we outline a selection of the literature describing biological features of CTCs with an impact on their metastasis forming ability in different GI cancers.

MACC1 as a Potential Target for the Treatment and Prevention of Breast Cancer

Metastasis associated in colon cancer 1 (MACC1) is an oncogene first identified in colon cancer. MACC1 has been identified in more than 20 different types of solid cancers. It is a key prognostic biomarker in clinical practice and is involved in recurrence, metastasis, and survival in many types of human cancers. MACC1 is significantly associated with the primary tumor, lymph node metastasis, distant metastasis classification, and clinical staging in patients with breast cancer (BC), and MACC1 overexpression is associated with reduced recurrence-free survival (RFS) and worse overall survival (OS) in patients. In addition, MACC1 is involved in BC progression in multiple ways. MACC1 promotes the immune escape of BC cells by affecting the infiltration of immune cells in the tumor microenvironment. Since the FGD5AS1/miR-497/MACC1 axis inhibits the apoptotic pathway in radiation-resistant BC tissues and cell lines, the MACC1 gene may play an important role in BC resistance to radiation. Since MACC1 is involved in numerous biological processes inside and outside BC cells, it is a key player in the tumor microenvironment. Focusing on MACC1, this article briefly discusses its biological effects, emphasizes its molecular mechanisms and pathways of action, and describes its use in the treatment and prevention of breast cancer.

High-performance glass filters for capturing and culturing circulating tumor cells and cancer-associated fibroblasts

Various liquid biopsy methods have been developed for the non-invasive and early detection of diseases. In particular, the detection of circulating tumor cells (CTCs) and cancer-associated fibroblasts (CAFs) in blood has been receiving a great deal of attention. We have been developing systems and materials to facilitate such liquid biopsies. In this study, we further developed glass filters (with various patterns of holes, pitches, and non-adhesive coating) that can capture CTCs, but not white blood cells. We optimized the glass filters to capture CTCs, and demonstrated that they could be used to detect CTCs from lung cancer patients. We also used the optimized glass filters for detecting CAFs. Additionally, we further developed a system for visualizing the captured cells on the glass filters. Finally, we demonstrated that we could directly culture the captured cells on the glass filters. Based on these results, our high-performance glass filters appear to be useful for capturing and culturing CTCs and CAFs for further examinations.

Single-cell infrared vibrational analysis by optical trapping mid-infrared photothermal microscopy

Single-cell analysis by means of vibrational spectroscopy combined with optical trapping is a reliable platform for unveiling cell-to-cell heterogeneities in vast populations. Although infrared (IR) vibrational spectroscopy provides rich molecular fingerprint information on biological samples in a label-free manner, its application with optical trapping has never been achieved due to weak gradient forces generated by the diffraction-limited focused IR beam and strong background of water absorption. Herein, we present single-cell IR vibrational analysis that incorporates mid-infrared photothermal (MIP) microscopy with optical trapping. Optically trapped single polymer particles and red blood cells (RBCs) in blood could be chemically identified owing to their IR vibrational fingerprints. This single-cell IR vibrational analysis further allowed us to probe the chemical heterogeneities of RBCs originating from the variation in the intracellular characteristics. Our demonstration paves the way for the IR vibrational analysis of single cells and chemical characterization in various fields.

New Method for Counting and Picking Out Single Circulating Tumor Cells from Microliter-Volume Samples for Tumor Progression Surveillance and Single-Cell Heterogeneity Analysis

Circulating tumor cells (CTCs) are crucial in tumor progression and metastasis, but the knowledge of their roles grows slowly at single-cell levels. Characterizing the rarity and fragility of CTCs by nature, highly stable and efficient single-CTC sampling methods are still lacking, which impedes the development of single-CTC analysis. Herein, an improved, capillary-based single-cell sampling (SiCS) method, the so-called bubble-glue single-cell sampling (bubble-glue SiCS), is introduced. Benefiting from the characteristic that the cells tend to adhere to air bubbles in the solution, single cells can be sampled with bubbles as low as 20 pL with a self-designed microbubble-volume-controlled system. Benefiting from the excellent maneuverability, single CTCs are sampled directly from 10 μL volume of real blood samples after fluorescent labeling. Meanwhile, over 90% of the CTCs obtained survived and well proliferated after the bubble-glue SiCS process, which showed considerable superiority for downstream single-CTC profiling. Furthermore, a highly metastatic breast cancer model of the 4T1 cell line in vivo was employed for the real blood sample analysis. Increases in CTC numbers were observed during the tumor progression process, and significant heterogeneities among individual CTCs were discovered. In all, we propose a novel avenue for target SiCS and provide an alternative technique route for CTC separation and analysis.

Vascular regulation of disseminated tumor cells during metastatic spread

Cancer cells can travel to other organs via interconnected vascular systems to form new lesions in a process known as metastatic spread. Unfortunately, metastasis remains the leading cause of patient lethality. In recent years, it has been demonstrated that physical cues are just as important as chemical and genetic perturbations in driving changes in gene expression, cell motility, and survival. In this concise review, we focus on the physical cues that cancer cells experience as they migrate through the lymphatic and blood vascular networks. We also present an overview of steps that may facilitate organ specific metastasis.

Building a precision medicine infrastructure at a national level: The Swedish experience

Precision medicine has the potential to transform healthcare by moving from one-size-fits-all to personalised treatment and care. This transition has been greatly facilitated through new high-throughput sequencing technologies that can provide the unique molecular profile of each individual patient, along with the rapid development of targeted therapies directed to the Achilles heels of each disease. To implement precision medicine approaches in healthcare, many countries have adopted national strategies and initiated genomic/precision medicine initiatives to provide equal access to all citizens. In other countries, such as Sweden, this has proven more difficult due to regionally organised healthcare. Using a bottom-up approach, key stakeholders from academia, healthcare, industry and patient organisations joined forces and formed Genomic Medicine Sweden (GMS), a national infrastructure for the implementation of precision medicine across the country. To achieve this, Genomic Medicine Centres have been established to provide regionally distributed genomic services, and a national informatics infrastructure has been built to allow secure data handling and sharing. GMS has a broad scope focusing on rare diseases, cancer, pharmacogenomics, infectious diseases and complex diseases, while also providing expertise in informatics, ethical and legal issues, health economy, industry collaboration and education. In this review, we summarise our experience in building a national infrastructure for precision medicine. We also provide key examples how precision medicine already has been successfully implemented within our focus areas. Finally, we bring up challenges and opportunities associated with precision medicine implementation, the importance of international collaboration, as well as the future perspective in the field of precision medicine.

Challenges and future of HER2-positive gastric cancer therapy

Gastric cancer is the fifth most common cancer worldwide, and the treatment of advanced gastric cancer has relatively little progress. With the continuous development of molecularly targeted therapy for tumors, it has been discovered that human epidermal growth factor receptor 2 (HER2) contributes to the poor prognosis and pathogenesis of various cancers. In order to treat HER2-positive advanced gastric cancer, Trastuzumab has emerged as the first first-line targeted medication used in conjunction with chemotherapy. The consequent trastuzumab resistance has become an important issue, and various new HER2-targeted gastric cancer drugs are emerging to address this challenge. This review's primary concern is the drug mechanism of various HER2-positive gastric cancer targeted therapy and fresh techniques of detection.

Recent Advances in Methods for Circulating Tumor Cell Detection

Circulating tumor cells (CTCs) are released from primary tumors and transported through the body via blood or lymphatic vessels before settling to form micrometastases under suitable conditions. Accordingly, several studies have identified CTCs as a negative prognostic factor for survival in many types of cancer. CTCs also reflect the current heterogeneity and genetic and biological state of tumors; so, their study can provide valuable insights into tumor progression, cell senescence, and cancer dormancy. Diverse methods with differing specificity, utility, costs, and sensitivity have been developed for isolating and characterizing CTCs. Additionally, novel techniques with the potential to overcome the limitations of existing ones are being developed. This primary literature review describes the current and emerging methods for enriching, detecting, isolating, and characterizing CTCs.

Liquid biopsies: the future of cancer early detection

Cancer is a worldwide pandemic. The burden it imposes grows steadily on a global scale causing emotional, physical, and financial strains on individuals, families, and health care systems. Despite being the second leading cause of death worldwide, many cancers do not have screening programs and many people with a high risk of developing cancer fail to follow the advised medical screening regime due to the nature of the available screening tests and other challenges with compliance. Moreover, many liquid biopsy strategies being developed for early detection of cancer lack the sensitivity required to detect early-stage cancers. Early detection is key for improved quality of life, survival, and to reduce the financial burden of cancer treatments which are greater at later stage detection. This review examines the current liquid biopsy market, focusing in particular on the strengths and drawbacks of techniques in achieving early cancer detection. We explore the clinical utility of liquid biopsy technologies for the earlier detection of solid cancers, with a focus on how a combination of various spectroscopic and -omic methodologies may pave the way for more efficient cancer diagnostics.

In Vivo Detection of Circulating Cancer-Associated Fibroblasts in Breast Tumor Mouse Xenograft: Impact of Tumor Stroma and Chemotherapy

Cancer-associated fibroblasts (CAFs) are important drivers in the tumor microenvironment and facilitate the growth and survival of tumor cells, as well as metastasis formation. They may travel together with tumor cells to support their survival and aid in the formation of a metastatic niche. In this study, we aimed to study circulating CAFs (cCAFs) and circulating tumor cells (CTCs) in a preclinical breast tumor model in mice in order to understand the effect of chemotherapy on cCAFs and CTC formation. Tumors with MDA-MB-231 human breast tumor cells with/without primary human mammary fibroblasts (representing CAFs) were coinjected in SCID mice to develop tumors. We found that the tumors with CAFs grew faster than tumors without CAFs. To study the effect of the stroma on CTCs and cCAFs, we isolated cells using microsieve filtration technology and established ITGA5 as a new cCAF biomarker, which showed good agreement with the CAF markers FAP and α-SMA. We found that ITGA5+ cCAFs shed in the blood of mice bearing stroma-rich coinjection-based tumors, while there was no difference in CTC formation. Although treatment with liposomal doxorubicin reduced tumor growth, it increased the numbers of both cCAFs and CTCs in blood. Moreover, cCAFs and CTCs were found to form clusters in the chemotherapy-treated mice. Altogether, these findings indicate that the tumor stroma supports tumor growth and the formation of cCAFs. Furthermore, chemotherapy may exacerbate the formation of cCAFs and CTCs, which may eventually support the formation of a metastasis niche in breast cancer.

Detection of rare CTCs by electrochemical biosensor built on quaternary PdPtCuRu nanospheres with mesoporous architectures

Circulating tumor cells (CTCs) are promising liquid biopsy biomarkers for early cancer detection and anti-cancer therapy evaluation. The ultra-low abundance of CTCs in blood samples requires highly sensitive and accurate detection ways. In this study, we propose the design of a dual-recognition electrochemical biosensor to improve both the specificity and signal response. PdPtCuRu mesoporous nanospheres (PdPtCuRu MNSs) with excellent three dimensions (3D) nanopore structures were synthesized by one-pot method and connected to mucin 1 (MUC1) aptamer to serve as signal amplification probe. Besides, superconductive carbon black, Ketjen Black (KB), and gold nanoparticles (AuNPs) modified organometallic frame (CeMOF-Au) were combined to work as signal transducer. The characteristic branching structure of KB provides abundant contact points to load CeMOF-Au to heighten the interface electron transfer rate. In addition, AuNPs were reduced on the surface of CeMOF, which could effectively bind the capture antibody and further enhance the conductivity. Under the optimized condition, the limit of detection (LOD) of the as-constructed biosensor was less than 10 cells mL^-1 for model A549 cells, and showed good specificity and accuracy in spiked serum samples. We envision the as-proposed electrochemical biosensor would alternate as a useful tool for the clinical detection of CTCs for cancer diagnosis.

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.

Detection of Circulating Tumor Cell-Related Markers in Gynecologic Cancer Using Microfluidic Devices: A Pilot Study

The detection of circulating tumor cells (CTCs) is an emerging strategy for the early detection, prognostication, and identification of recurrent cancer. The clinical utility of CTC detection has been established, but few studies have employed this strategy for the detection of gynecologic cancers. Here, we present a novel, biochip-based microfluidic device for the detection of CTCs in gynecologic cancers. The study cohort included three patients with cervical cancer, eight with endometrial cancer, two with ovarian cancer, two with breast cancer, and one with vaginal small cell carcinoma. Four cancer type-specific molecular markers (PanCK, GATA3, HER2, and HE4), as well as CD13, were used for prognostication and recurrence detection, along with downstream genomic analysis. GATA3 and HER2 were markedly expressed in the patients with cervical cancer, and this expression was strongly correlated with the early detection of recurrent disease. All four molecular markers were expressed preoperatively in the patients with endometrial cancer, and the re-expression of different markers was observed at follow-up before recurrence was confirmed. CD13 was identified as an alternative prognostic marker for both cervical and endometrial cancer. Our pilot study indicated that the novel CTC detection system can be used for prognostication and early detection of disease recurrence, which needed further investigation.

Current Status of Circulating Tumor Cells in Head and Neck Squamous Cell Carcinoma: A Review

OBJECTIVE

Circulating tumor cells (CTCs) are found in the blood of patients with cancer, including head and neck squamous cell carcinomas (HNSCCs). The aim is to review the most up-to-date status of CTCs for applications in patients with HNSCC.

DATA SOURCES

English articles in PubMed.

REVIEW METHODS

All the studies on CTCs in HNSCCs in the literature were reviewed.

CONCLUSIONS

There is emerging information on the diagnostic and prognostic value of CTCs in HNSCCs. Evidence also highlights the advantages of various downstream analysis approaches over circulating tumor DNA (ctDNA), such as single-CTC analysis, ex vivo, and in vivo expansion of CTCs. Multiple phenotypic surface markers (cytokeratins, EpCAM, vimentin, etc.), used for CTCs characterization using different immunoassays, could predict disease progression as well as patients' response to treatment efficacy. Immune checkpoint inhibitors' status in CTCs could also provide better insight into treatment. Clonal expansion of CTCs and single-cell analysis of CTCs are the most emerging fields nowadays which may offer an understanding of the mechanism of tumor evolution as well as therapeutic efficacy. Although several clinical trials are ongoing, limitations still exist in the detection and characterization of CTCs. Due to the lack of a gold standard protocol, the sensitivity and specificity of CTC enumeration methods vary.

IMPLICATIONS FOR PRACTICE

Prospective clinical trials are still needed before CTCs can be employed as diagnostic and prognostic markers in the clinical management of patients with HNSCC.

Updated Views in Targeted Therapy in the Patient with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most frequent form of lung cancer and represents a set of histological entities that have an ominous long-term prognosis, for example, adenocarcinoma, squamous carcinoma and large cell carcinoma. Both small cell and non-small cell lung cancer are the main causes of oncological death and the oncological diseases with the highest incidence worldwide. With regard to clinical approaches for NSCLC, several advances have been achieved in diagnosis and treatment; the analysis of different molecular markers has led to the development of new targeted therapies that have improved the prognosis for selected patients. Despite this, most patients are diagnosed in an advanced stage, presenting a limited life expectancy with an ominous short-term prognosis. Numerous molecular alterations have been described in recent years, allowing for the development of therapies directed against specific therapeutic targets. The correct identification of the expression of different molecular markers has allowed for the individualization of treatment throughout the disease course, expanding the available therapeutic arsenal. The purpose of this article is to summarize the main characteristics of NSCLC and the advances that have occurred in the use of targeted therapies, thus explaining the limitations that have been observed in the management of this disease.

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.

Correlation between mesenchymal circulating tumor cells and prognosis of urologic malignancies: a single-center retrospective analysis

OBJECTIVE

To evaluate the correlation of circulating tumor cells (CTCs) and mesenchymal CTCs (M-CTCs) with clinical characteristics and survival of patients with urologic malignancies.

METHODS

The clinical data of 52 patients with urinary system malignancy in Henan Provincial People's Hospital were retrospectively analyzed (40 cases of renal malignant tumor, 7 cases of prostate cancer, 3 cases of urothelial carcinoma, 1 case of testis cancer, and 1 case of penile cancer). The CTC counts of patients were collected, and the expression of epithelial-mesenchymal transition phenotype in CTCs was evaluated. The relationship of different types of CTC counts with tumor stage, location, size, metastasis, and differentiation, as well as their effect on progression-free survival (PFS) were analyzed.

RESULTS

We detected CTCs in all patients with urinary system malignancy. The positive rates of epithelial CTCs (E-CTC), M-CTCs, and epithelial/mesenchymal CTCs (E/M-CTCs) were 34.62%, 26.92% and 94.23%, respectively. Total CTCs (T-CTCs), M-CTCs and E/M-CTCs were correlated with distant metastasis (Z=-3.052, -3.574, -2.898; all P<0.005). M-CTC count was correlated with lymph node metastasis (Z=-3.125; P=0.002). Furthermore, the presence of T-CTCs ≥13.5, M-CTC ≥0.5 or E/M-CTCs ≥9.5 per 5 ml of blood was correlated with worse PFS in patients with urinary system malignancy.

CONCLUSIONS

M-CTC and E/M-CTC counts correlate with the prognosis of patients with urinary system malignancy. Higher M-CTC and E/M-CTC counts are risk factors for worse prognosis in patients with urinary system malignancies. All in all, M-CTC count is a valuable tumor biomarker for urologic malignancies.

Liquid biopsy approaches and immunotherapy in colorectal cancer for precision medicine: Are we there yet?

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally, with nearly half of patients detected in the advanced stages. This is due to the fact that symptoms associated with CRC often do not appear until the cancer has reached an advanced stage. This suggests that CRC is a cancer with a slow progression, making it curable and preventive if detected in its early stage. Therefore, there is an urgent clinical need to improve CRC early detection and personalize therapy for patients with this cancer. Recently, liquid biopsy as a non-invasive or nominally invasive approach has attracted considerable interest for its real-time disease monitoring capability through repeated sample analysis. Several studies in CRC have revealed the potential for liquid biopsy application in a real clinical setting using circulating RNA/miRNA, circulating tumor cells (CTCs), exosomes, etc. However, Liquid biopsy still remains a challenge since there are currently no promising results with high specificity and specificity that might be employed as optimal circulatory biomarkers. Therefore, in this review, we conferred the plausible role of less explored liquid biopsy components like mitochondrial DNA (mtDNA), organoid model of CTCs, and circulating cancer-associated fibroblasts (cCAFs); which may allow researchers to develop improved strategies to unravel unfulfilled clinical requirements in CRC patients. Moreover, we have also discussed immunotherapy approaches to improve the prognosis of MSI (Microsatellite Instability) CRC patients using neoantigens and immune cells in the tumor microenvironment (TME) as a liquid biopsy approach in detail.

Integrating Cutting-Edge Methods to Oral Cancer Screening, Analysis, and Prognosis

Oral cancer (OC) has become a significant barrier to health worldwide due to its high morbidity and mortality rates. OC is among the most prevalent types of cancer that affect the head and neck region, and the overall survival rate at 5 years is still around 50%. Moreover, it is a multifactorial malignancy instigated by genetic and epigenetic variabilities, and molecular heterogeneity makes it a complex malignancy. Oral potentially malignant disorders (OPMDs) are often the first warning signs of OC, although it is challenging to predict which cases will develop into malignancies. Visual oral examination and histological examination are still the standard initial steps in diagnosing oral lesions; however, these approaches have limitations that might lead to late diagnosis of OC or missed diagnosis of OPMDs in high-risk individuals. The objective of this review is to present a comprehensive overview of the currently used novel techniques viz., liquid biopsy, next-generation sequencing (NGS), microarray, nanotechnology, lab-on-a-chip (LOC) or microfluidics, and artificial intelligence (AI) for the clinical diagnostics and management of this malignancy. The potential of these novel techniques in expanding OC diagnostics and clinical management is also reviewed.

Advances in early detection methods for solid tumors

During the last decade, non-invasive methods such as liquid biopsy have slowly replaced traditional imaging and invasive pathological methods used to diagnose and monitor cancer. Improvements in the available detection methods have enabled the early screening and diagnosis of solid tumors. In addition, advances in early detection methods have made the continuous monitoring of tumor progression using repeat sampling possible. Previously, the focus of liquid biopsy techniques included the following: 1) the isolation of circulating tumor cells, circulating tumor DNA, and extracellular tumor vesicles from solid tumor cells in the patient's blood; in addition to 2) analyzing genomic and proteomic data contained within the isolates. Recently, there has been a rapid devolvement in the techniques used to isolate and analyze molecular markers. This rapid evolvement in detection techniques improves their accuracy, especially when few samples are available. In addition, there is a tremendous expansion in the acquisition of samples and targets for testing; solid tumors can be detected from blood and other body fluids. Test objects have also expanded from samples taken directly from cancer to include indirect objects affected in cancer development. Liquid biopsy technology has limitations. Even so, this detection technique is the key to a new phase of oncogenetics. This review aims to provide an overview of the current advances in liquid biopsy marker selection, isolation, and detection methods for solid tumors. The advantages and disadvantages of liquid biopsy technology will also be explored.

Analytical performance of the FDA-cleared Parsortix® PC1 system

Introduction

The Parsortix® PC1 system, Food and Drug Administration (FDA) cleared for use in metastatic breast cancer (MBC) patients, is an epitope-independent microfluidic device for the capture and harvest of circulating tumor cells from whole blood based on cell size and deformability. This report details the analytical characterization of linearity, detection limit, precision, and reproducibility for this device.

Methods

System performance was determined using K2-EDTA blood samples collected from self-declared healthy female volunteers (HVs) and MBC patients spiked with prelabeled cultured breast cancer cell lines (SKBR3, MCF7, or Hs578T). Samples were processed on Parsortix® PC1 systems and captured cells were harvested and enumerated.

Results

The system captured and harvested live SKBR3, MCF7, and Hs578T cells and fixed SKBR3 cells linearly between 2 and ~100 cells, with average harvest rates of 69%, 73%, 79%, and 90%, respectively. To harvest ≥1 cell ≥95% of the time, the system required 3, 5 or 4 live SKBR3, MCF7 or Hs578T cells, respectively. Average harvest rates from precision studies using 5, 10, and ~50 live cells spiked into blood for each cell line ranged from 63.5% to 76.2%, with repeatability and reproducibility percent coefficient of variation (%CV) estimates ranging from 12.3% to 32.4% and 13.3% to 34.1%, respectively. Average harvest rates using ~20 fixed SKBR3 cells spiked into HV and MBC patient blood samples were 75.0% ± 16.1% (%CV = 22.3%) and 68.4% ± 14.3% (%CV = 21.1%), respectively.

Conclusions

These evaluations demonstrate the Parsortix® PC1 system linearly and reproducibly harvests tumor cells from blood over a range of 1 to ~100 cells.

Exosomes in sarcoma: Prospects for clinical applications

Sarcoma is a group of rare and heterogeneous mesenchymal tumors, prone to late diagnosis and poor prognosis. Exosomes are cell-derived small extracellular vesicles found in most body fluids and contain nucleic acids, proteins, lipids, and other molecules. Qualitative and quantitative changes of exosomes and the contents are associated with sarcoma progression, exhibiting their potential as biomarkers. Exosomes possess the capacity of evading immune responses, bioactivity for trafficking, tumor tropism, and lesion residence. Thus, exosomes could be engineered as tumor-specific vehicles in drugs and RNA delivery systems. Exosomes might also serve as therapeutic targets in targeted therapy and immunotherapy and be involved in chemotherapy resistance. Here, we provide a comprehensive summary of exosome applications in liquid biopsy-based diagnosis and explore their implications in the delivery system, targeted therapy, and chemotherapy resistance of sarcoma. Moreover, challenges in exosome clinical applications are raised and some future research directions are proposed.

Detection of Single Non-small Cell Lung Cancer Cell Multidrug Resistance with Single-Cell Bioanalyzer

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer death in the world. Despite the development of various lung cancer treatment methods, including surgery, radiation therapy, endocrine therapy, immunotherapy, and gene therapy, chemotherapy remains the most common approach for treating cancer. The risk of tumors acquiring resistance to chemotherapy remains a significant hurdle to the use of this approach for the successful treatment of various types of cancer. The majority of cancer-related deaths are related to metastasis. Circulating tumor cells (CTCs) are cells that have been detached from the primary tumor or have metastasized and entered the circulation. CTCs can cause metastases in various organs by reaching them through the bloodstream. The CTCs exist in peripheral blood as single cells or as oligoclonal clusters of tumor cells along with platelets and lymphocytes. The detection of CTCs is an important component of liquid biopsy which aids in the diagnosis, treatment, and prognosis of cancer. Here, we describe a method for extracting CTCs from the tumor of patients and using the microfluidic single-cell technique to study the inhibition of multidrug resistance due to drug efflux on a single cancer cell, to propose novel methods that can provide clinicians with more appropriate choices in their diagnostic and treatment approaches.

Revisiting laminin and extracellular matrix remodeling in metastatic squamous cell carcinoma: What have we learned after more than four decades of research?

Patients with squamous cell carcinoma (SCC) have significantly lower survival upon the development of distant metastases. The extracellular matrix (ECM) is a consistent yet dynamic influence on the metastatic capacity of SCCs. The ECM encompasses a milieu of structural proteins, signaling molecules, and enzymes. Just over 40 years ago, the fibrous ECM glycoprotein laminin was identified. Roughly four decades of research have revealed a pivotal role of laminins in metastasis. However, trends in ECM alterations in some cancers have been applied broadly to all metastatic diseases, despite evidence that these characteristics vary by tumor type. We will summarize how laminins influence the SCC metastatic process exclusively. Enhanced laminin protein deposition occurs at the invasive edge of SCC tumors, which correlates with elevated levels of laminin-binding β1 integrins on SCC cells, increased MMP-3 presence, worse prognosis, and lymphatic dissemination. Although these findings are significant, gaps in knowledge of the formation of a premetastatic niche, the processes of intra- and extravasation, and the contributions of the ECM to SCC metastatic cell dormancy persist. Bridging these gaps requires novel in vitro systems and animal models that reproduce tumor-stromal interactions and spontaneous metastasis seen in the clinic. These advances will allow accurate assessment of laminins to predict responders to transforming growth factor-β inhibitors and immunotherapy, as well as potential combinatorial therapies with the standard of care. Such clinical interventions may drastically improve quality of life and patient survival by explicitly targeting SCC metastasis.

Circulating Tumor Cells as Biomarkers for Renal Cell Carcinoma: Ready for Prime Time?

Renal cell carcinoma (RCC) is among the 15 most common cancers worldwide, with rising incidence. In most cases, this is a silent disease until it reaches advance stages, demanding new effective biomarkers in all domains, from detection to post-therapy monitoring. Circulating tumor cells (CTC) have the potential to provide minimally invasive information to guide assessment of the disease's aggressiveness and therapeutic strategy, representing a special pool of neoplastic cells which bear metastatic potential. In some tumor models, CTCs' enumeration has been associated with prognosis, but there is a largely unexplored potential for clinical applicability encompassing screening, diagnosis, early detection of metastases, prognosis, response to therapy and monitoring. Nonetheless, lack of standardization and high cost hinder the translation into clinical practice. Thus, new methods for collection and analysis (genomic, proteomic, transcriptomic, epigenomic and metabolomic) are needed to ascertain the role of CTC as a RCC biomarker. Herein, we provide a critical overview of the most recently published data on the role and clinical potential of CTCs in RCC, addressing their biology and the molecular characterization of this remarkable set of tumor cells. Furthermore, we highlight the existing and emerging techniques for CTC enrichment and detection, exploring clinical applications in RCC. Notwithstanding the notable progress in recent years, the use of CTCs in a routine clinical scenario of RCC patients requires further research and technological development, enabling multimodal analysis to take advantage of the wealth of information they provide.

Technologies for Viable Circulating Tumor Cell Isolation

The spread of tumor cells throughout the body by traveling through the bloodstream is a critical step in metastasis, which continues to be the main cause of cancer-related death. The detection and analysis of circulating tumor cells (CTCs) is important for understanding the biology of metastasis and the development of antimetastatic therapy. However, the isolation of CTCs is challenging due to their high heterogeneity and low representation in the bloodstream. Different isolation methods have been suggested, but most of them lead to CTC damage. However, viable CTCs are an effective source for developing preclinical models to perform drug screening and model the metastatic cascade. In this review, we summarize the available literature on methods for isolating viable CTCs based on different properties of cells. Particular attention is paid to the importance of in vitro and in vivo models obtained from CTCs. Finally, we emphasize the current limitations in CTC isolation and suggest potential solutions to overcome them.

Crucial roles of circulating tumor cells in the metastatic cascade and tumor immune escape: biology and clinical translation

Cancer-related deaths are mainly caused by metastatic spread of tumor cells from the primary lesion to distant sites via the blood circulation. Understanding the mechanisms of blood-borne tumor cell dissemination by the detection and molecular characterization of circulating tumor cells (CTCs) in the blood of patients with cancer has opened a new avenue in cancer research. Recent technical advances have enabled a comprehensive analysis of the CTCs at the genome, transcriptome and protein level as well as first functional studies using patient-derived CTC cell lines. In this review, we describe and discuss how research on CTCs has yielded important insights into the biology of cancer metastasis and the response of patients with cancer to therapies directed against metastatic cells. Future investigations will show whether CTCs leaving their primary site are more vulnerable to attacks by immune effector cells and whether cancer cell dissemination might be the 'Achilles heel' of metastatic progression. Here, we focus on the lessons learned from CTC research on the biology of cancer metastasis in patients with particular emphasis on the interactions of CTCs with the immune system. Moreover, we describe and discuss briefly the potential and challenges for implementing CTCs into clinical decision-making including detection of minimal residual disease, monitoring efficacies of systemic therapies and identification of therapeutic targets and resistance mechanisms.

Deep transfer learning enables lesion tracing of circulating tumor cells

Liquid biopsy offers great promise for noninvasive cancer diagnostics, while the lack of adequate target characterization and analysis hinders its wide application. Single-cell RNA sequencing (scRNA-seq) is a powerful technology for cell characterization. Integrating scRNA-seq into a CTC-focused liquid biopsy study can perhaps classify CTCs by their original lesions. However, the lack of CTC scRNA-seq data accumulation and prior knowledge hinders further development. Therefore, we design CTC-Tracer, a transfer learning-based algorithm, to correct the distributional shift between primary cancer cells and CTCs to transfer lesion labels from the primary cancer cell atlas to CTCs. The robustness and accuracy of CTC-Tracer are validated by 8 individual standard datasets. We apply CTC-Tracer on a complex dataset consisting of RNA-seq profiles of single CTCs, CTC clusters from a BRCA patient, and two xenografts, and demonstrate that CTC-Tracer has potential in knowledge transfer between different types of RNA-seq data of lesions and CTCs.

Circulating Tumor Cells as a Predictive Biomarker in Resectable Lung Cancer: A Systematic Review and Meta-Analysis

Background: In breast, prostate, and other epithelial tumors, circulating tumor cells (CTC) in peripheral blood may predict survival. Our study evaluated the prognostic significance of baseline and postoperative CTC in patients with early non-small cell lung cancer (NSCLC) through a meta-analytic approach. Methods: Prospective studies comparing survival outcomes between positive (CTC+) and negative CTC (CTC−) patients were systematically searched. Primary outcomes were overall (OS) and disease-free survival (DFS) with hazard ratio (HR) and 95% confidence interval (CI) as the effect measure. Pooled HR determined the prognostic role under a fixed-effect or random-effect model depending on heterogeneity. Results: Eighteen studies with 1321 patients were eligible. CTC+ patients were associated with an increased risk of death (HR 3.53, 95% CI 2.51−4.95; p < 0.00001) and relapse (HR 2.97, 95% CI 2.08−4.22; p < 0.00001). Subgroup analysis results were consistent in different subsets, including time points (baseline and postoperative) and sources (peripheral and pulmonary vein) of blood collection, detection methods (label-free, label-dependent, and RT-PCR), and follow-up duration. Conclusion: Our meta-analysis revealed that CTC is a promising predictive biomarker for stratifying survival outcomes in patients with early-stage NSCLC. However, future studies are required to validate these findings and standardize detection methods.

Emerging metabolomic tools to study cancer metastasis

Metastasis is responsible for 90% of deaths in patients with cancer. Understanding the role of metabolism during metastasis has been limited by the development of robust and sensitive technologies that capture metabolic processes in metastasizing cancer cells. We discuss the current technologies available to study (i) metabolism in primary and metastatic cancer cells and (ii) metabolic interactions between cancer cells and the tumor microenvironment (TME) at different stages of the metastatic cascade. We identify advantages and disadvantages of each method and discuss how these tools and technologies will further improve our understanding of metastasis. Studies investigating the complex metabolic rewiring of different cells using state-of-the-art metabolomic technologies have the potential to reveal novel biological processes and therapeutic interventions for human cancers.

Integrated analysis revealing the role of TET3-mediated MUC13 promoter hypomethylation in hepatocellular carcinogenesis

Aim: To explore the function and underlying mechanism of MUC13 in hepatocellular carcinoma (HCC) oncogenesis. Materials & Methods: Online databases and software were used to perform analyses of expression, methylation and enrichment pathway. Experiments were performed to confirm the results using HCC cells in vitro. Results: MUC13 was upregulated in HCC and liver cancer stem cells (CSCs) and had a positive influence on CSC generation. Further analyses revealed that MUC13 with promoter hypomethylated was regulated by DNA demethylase TET3, which was overexpressed in HCC and liver CSCs. Conclusion: These results strongly suggested that high TET3 expression in liver CSCs may mediate MUC13 upregulation via promoter hypomethylation and thereby contribute to hepatocellular carcinogenesis.

Towards the Search for Potential Biomarkers in Osteosarcoma: State-of-the-Art and Translational Expectations

Osteosarcoma represents a rare cause of cancer in the general population, accounting for <1% of malignant neoplasms globally. Nonetheless, it represents the main cause of malignant bone neoplasm in children, adolescents and young adults under 20 years of age. It also presents another peak of incidence in people over 50 years of age and is associated with rheumatic diseases. Numerous environmental risk factors, such as bone diseases, genetics and a history of previous neoplasms, have been widely described in the literature, which allows monitoring a certain group of patients. Diagnosis requires numerous imaging tests that make it possible to stratify both the local involvement of the disease and its distant spread, which ominously determines the prognosis. Thanks to various clinical trials, the usefulness of different chemotherapy regimens, radiotherapy and surgical techniques with radical intent has now been demonstrated; these represent improvements in both prognosis and therapeutic approaches. Osteosarcoma patients should be evaluated in reference centres by multidisciplinary committees with extensive experience in proper management. Although numerous genetic and rheumatological diseases and risk factors have been described, the use of serological, genetic or other biomarkers has been limited in clinical practice compared to other neoplasms. This limits both the initial follow-up of these patients and screening in populations at risk. In addition, we cannot forget that the diagnosis is mainly based on the direct biopsy of the lesion and imaging tests, which illustrates the need to study new diagnostic alternatives. Therefore, the purpose of this study is to review the natural history of the disease and describe the main biomarkers, explaining their clinical uses, prognosis and limitations.

"Friends and foes" of multiple myeloma measurable/minimal residual disease evaluation by next generation flow

Next Generation Flow (NGF) represents a gold standard for the evaluation of Minimal Residual Disease (MRD) in Multiple Myeloma (MM) patients at any stage of treatment. Although the assessment of MRD is still not universally employed in clinical practice, numerous studies have demonstrated the strength of MRD as a reliable predictor of long-term outcome, and its potential to supersede the prognostic value of CR. The possibility to acquire millions of events, in combination with the use of standard reagents and a good expertise in the analysis of rare populations, led to high chance of success and a sensitivity of 10-6 that is superimposable to the one of Next Generation Sequencing molecular techniques. Some minor bias, correlated to the protocols applied, to the quality of samples and to the high heterogeneity of plasma cells phenotype, may be overcome using standard protocols and having at disposition personnel expertise for MRD analysis. With the use of NGF we can today enter a new phase of the quantification of residual disease, switching from the definition of "minimal" residual disease to "measurable" residual disease. This review takes account of the principle "friends and foes" of Myeloma "Measurable" Residual Disease evaluation by NGF, to give insights into the potentiality of this technique. The optimization of the quality of BM samples and the analytic expertise that permits to discriminate properly the rare pathologic clones, are the keys for obtaining results with a high clinical value that could be of great impact and relevance in the future.

Hydrogel-Based Biosensors

There is an increasing interest in sensing applications for a variety of analytes in aqueous environments, as conventional methods do not work reliably under humid conditions or they require complex equipment with experienced operators. Hydrogel sensors are easy to fabricate, are incredibly sensitive, and have broad dynamic ranges. Experiments on their robustness, reliability, and reusability have indicated the possible long-term applications of these systems in a variety of fields, including disease diagnosis, detection of pharmaceuticals, and in environmental testing. It is possible to produce hydrogels, which, upon sensing a specific analyte, can adsorb it onto their 3D-structure and can therefore be used to remove them from a given environment. High specificity can be obtained by using molecularly imprinted polymers. Typical detection principles involve optical methods including fluorescence and chemiluminescence, and volume changes in colloidal photonic crystals, as well as electrochemical methods. Here, we explore the current research utilizing hydrogel-based sensors in three main areas: (1) biomedical applications, (2) for detecting and quantifying pharmaceuticals of interest, and (3) detecting and quantifying environmental contaminants in aqueous environments.

Quantitative Phase Imaging Detecting the Hypoxia-Induced Patterns in Healthy and Neoplastic Human Colonic Epithelial Cells

Hypoxia is a frequent phenomenon during carcinogenesis and may lead to functional and structural changes in proliferating cancer cells. Colorectal cancer (CRC) is one of the most common neoplasms in which hypoxia is associated with progression. The aim of this study was to assess the optical parameters and microanatomy of CRC and the normal intestinal epithelium cells using the digital holotomography (DHT) method. The examination was conducted on cancer (HT-29, LoVo) and normal colonic cells (CCD-18Co) cultured in normoxic and hypoxic environments. The assessment included optical parameters such as the refractive index (RI) and dry mass as well as the morphological features. Hypoxia decreased the RI in all cells as well as in their cytoplasm, nucleus, and nucleoli. The opposite tendency was noted for spheroid-vesicular structures, where the RI was higher for the hypoxic state. The total volume of hypoxic CCD-18Co and LoVo cells was decreased, while an increase in this parameter was observed for HT-29 cells. Hypoxia increased the radius and cell volume, including the dry mass of the vesicular content. The changes in the optics and morphology of hypoxic cells may suggest the possibility of using DHT in the detection of circulating tumor cells (CTCs).

A pilot study of the relative number of circulating tumor cells and leukocytes containing actin-binding proteins in head and neck cancer patients

Circulating tumor cells (CTCs) play an important role in tumor metastases, which is positively correlated with an increased risk of death. Actin-binding proteins, including cofilin (CFL1), profilin 1 (PFN1), and adenylate cyclase-associated protein 1 (CAP1), are thought to be involved in tumor cell motility and metastasis, specifically in head and neck squamous cell carcinoma (HNSCC). However, currently, there are no published studies on CFL1, PFN1, and CAP1 in CTCs and leukocytes in HNSCC patients. We assessed serum levels of CFL1, PFN1, and CAP1 and the number of CTCs and leukocytes containing these proteins in blood from 31 HNSCC patients (T1-4N0-2M0). The analysis used flow cytometry and an enzyme-linked immunosorbent assay kit. We found that CAP1 + CTCs and CAP1 + leukocyte subpopulations were prevalent in these HNSCC patient samples, while the prevalence rates of CFL1 + and PFN1 + CTCs were relatively low. Patients with stage T2-4N1-2M0 had CFL1 + and PFN1 + CTCs with an elevated PFN1 serum level, compared with the T1-3N0M0 group. In summary, the PFN1 serum level and the relative number of PFN1 +CD326 + CTCs could be valuable prognostic markers for HNSCC metastases. The current study is the first to obtain data regarding the contents of actin-binding proteins (ABPs) in CTCs, and leukocytes in blood from HNSCC patients. This is also the first to assess the relationship between the number of CTCs subgroups and disease characteristics.

Circulating Tumor Cells in Colorectal Cancer: Detection Systems and Clinical Utility

Colorectal cancer (CRC) is the third most common cancer worldwide. The high mortality from CRC is mainly related to metastasis affecting distant organs and their function. Dissemination of tumor cells from the primary tumor and hematogeneous spread are considered crucial in the formation of tumor metastases. The analysis of circulating tumor cells (CTCs) and CTC clusters in the blood can be used for the early detection of invasive cancer. Moreover, CTCs have a prognostic significance in the monitoring of a malignant disease or the response to chemotherapy. This work presents an overview of the research conducted on CTCs with the aim of finding suitable detection systems and assessing the possibility of clinical applications in patients with CRC.

Clinical Applications of Liquid Biopsy in Colorectal Cancer Screening: Current Challenges and Future Perspectives

Colorectal cancer (CRC) represents the third most prevalent cancer worldwide and a leading cause of mortality among the population of western countries. However, CRC is frequently a preventable malignancy due to various screening tests being available. While failing to obtain real-time data, current screening methods (either endoscopic or stool-based tests) also require disagreeable preparation protocols and tissue sampling through invasive procedures, rendering adherence to CRC screening programs suboptimal. In this context, the necessity for novel, less invasive biomarkers able to identify and assess cancer at an early stage is evident. Liquid biopsy comes as a promising minimally invasive diagnostic tool, able to provide comprehensive information on tumor heterogeneity and dynamics during carcinogenesis. This review focuses on the potential use of circulating tumor cells (CTCs), circulating nucleic acids (CNAs) and extracellular vesicles as emerging liquid biopsy markers with clinical application in the setting of CRC screening. The review also examines the opportunity to implement liquid biopsy analysis during everyday practice and provides highlights on clinical trials researching blood tests designed for early cancer diagnosis. Additionally, the review explores potential applications of liquid biopsies in the era of immunotherapy.

Personalized cancer care

ABSTRACT

The completion of the Human Genome Project in 2003 has led to the development of molecular profiling platforms that have changed the trajectory of cancer care. These technologies continue to advance, and with the development of next-generation sequencing, targeted gene panels are now commercially available to analyze DNA, RNA, and protein biomarkers and can detect germline (inherited) and somatic (acquired) mutations through genomic profiling of tumor tissue and/or blood. These targeted panels are useful in practice and can affect clinical decision making. The results of molecular profiling can lead to an increasing number of FDA approved treatment options and/or clinical trial opportunities with novel drugs linked to these alterations, most notably in more advanced disease. This ability to individualize treatment options has led to precision medicine, providing a more personalized approach to cancer care.