Rapid clearance of fetal DNA from maternal plasma

Exploring Early Kinetic Profiles of CEA, ctDNA and cfDNA in Patients With RAS-/BRAF-Mutated Metastatic Colorectal Cancer

INTRODUCTION

Patients with metastatic colorectal cancer (mCRC) respond differently to first-line chemotherapy. Early identification of patients with limited or no clinical benefit could prompt a timelier introduction of second-line therapy and potentially lead to improved overall outcomes. Carcinoembryonic antigen (CEA) is currently the only blood-based marker in clinical use for disease control monitoring in mCRC. Circulating cell-free DNA (cfDNA), including circulating tumor DNA (ctDNA) could become a useful surrogate for oncological outcomes.

MATERIALS AND METHODS

Forty patients with RAS-/BRAF-mutated mCRC from the prospective NORDIC-VII trial (NCT00145314) were included. An exploratory model system was made to describe the early on-treatment kinetics of CEA, cfDNA and ctDNA during first-line oxaliplatin-based chemotherapy, and investigate the associations with radiological response, progression-free survival (PFS) and overall survival (OS).

RESULTS

Summary metrics were made, representing percentage change from treatment start to time-grid day 7 (P7), day 14 (P14), and day 49 (P49); slope from time-grid day 0 to 7 (S7), day 8 to 14 (S14), and day 15 to 49 (S49); and area under the curve from time-grid day 0 to 49 (AUC). Notably P49 and S49 for ctDNA and CEA were associated with radiological response and/or PFS. The early dynamics of the two markers differed substantially, with faster and more marked changes in ctDNA compared with CEA. Nine patients did not reach complete/near complete molecular ctDNA response close to first evaluation (∼week 8), a state associated with a short PFS (HR 2.72; 95% CI, 1.22-6.06; P = .01) and OS (HR 3.12; 95% CI, 1.35-7.23; P < .01). Contrary, twenty-two patients did not reach radiological response (i.e., complete or partial response) at first evaluation, but this was not associated with PFS (HR 1.21; 95% CI, 0.64-2.30; P = .55) nor OS (HR 1.37; 95% CI, 0.70-2.68; P = .37).

CONCLUSION

Early dynamics of ctDNA during first-line oxaliplatin-based chemotherapy hold prognostic value, supporting the idea of prospectively validating a ctDNA-RECIST framework in the early care pathway of mCRC patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00145314.

Development of a prediction model for ctDNA detection (Cir-Predict) in breast cancer

PURPOSE

The detection of circulating tumor DNA (ctDNA) is a valuable method to predict the risk of recurrence and to detect real-time gene changes. The amount of ctDNA is affected by many factors. Moreover, the detection rate of ctDNA varies from report to report.

METHODS

The present study evaluated differentially expressed genes using a DNA microarray assay for gene expression in tumors with and without detected ctDNA and constructed a prediction model for the detectability of ctDNA in breast tumor tissues. The model, named Cir-Predict, consisted of 126 probe sets (111 genes) and was constructed in a training set of breast cancer patients (n = 35) and validated in a validation set (n = 13).

RESULTS

The accuracy, sensitivity, and specificity in training and validation sets were over 90%, and Cir-Predict was significantly associated with ctDNA detection independently of the other conventional clinicopathological parameters in training and validation sets (P < 0.001, P = 0.014, respectively). Cir-Predict (+) was significantly associated with worse recurrence-free survival (P = 0.006). Pathway analysis revealed that nine pathways including tight junction and cell cycle tended to be related to ctDNA detectability.

CONCLUSION

Cir-Predict not only provides information useful for breast cancer treatment, but also helps the understanding of the mechanism by which ctDNA is detected.

Modulating cell-free DNA biology as the next frontier in liquid biopsies

Technical advances over the past two decades have enabled robust detection of cell-free DNA (cfDNA) in biological samples. Yet, higher clinical sensitivity is required to realize the full potential of liquid biopsies. This opinion article argues that to overcome current limitations, the abundance of informative cfDNA molecules - such as circulating tumor DNA (ctDNA) - collected in a sample needs to increase. To accomplish this, new methods to modulate the biological processes that govern cfDNA production, trafficking, and clearance in the body are needed, informed by a deeper understanding of cfDNA biology. Successful development of such methods could enable a major leap in the performance of liquid biopsies and vastly expand their utility across the spectrum of clinical care.

Full-Length Clonal Immunoglobulin Rearrangements in cfDNA: Improved Recovery and Sequencing

BACKGROUND

Circulating tumor DNA present in cell-free DNA (cfDNA) serves as diagnostic, predictive, and prognostic markers in cancer patients. In lymphoma patients, clonal immunoglobulin (cIg) sequences enable accurate identification of disease states. Despite its importance, there is sparse literature surrounding the preanalytical and analytical conditions that affect cIg detection in cfDNA. This study evaluates the effects of cfDNA isolation and next-generation sequencing (NGS) library preparation on IGH sequencing.

METHODS

Pooled plasma obtained from healthy donors and plasma collected from study participants (N = 118) enrolled in cross-sectional studies were analyzed. Two cfDNA isolation methods, paramagnetic bead and spin-column, were evaluated with plasma volume being variable. Two NGS library preparation procedures, single and dual library purification, were evaluated with cfDNA input being variable.

RESULTS

Paramagnetic bead-based cfDNA isolation improved recovery of cfDNA when compared to the column-based method. Higher purity of cfDNA resulted in more reproducible detection of cIg sequences. NGS library conditions affected IGH sequencing read depth, read diversity, and enrichment for full-length immunoglobulin sequences. A modified library procedure consisting of repeat library purifications improved the read depth of short and intermediate length targets independent of cfDNA input.

CONCLUSIONS

This is the first study to evaluate preanalytical and analytical factors that impact immunoglobulin sequencing in cfDNA. Our findings show optimal cfDNA isolation and library preparation procedures can improve the detection of clonal immunoglobulin rearrangements.

Noninvasive Prenatal Paternity Testing: A Review on Genetic Markers

Noninvasive prenatal paternity testing (NIPPT) is a crucial tool in forensic contexts, particularly in cases involving post-rape pregnancies. It enables judicial authorities and victims to promptly address these situations by determining the paternity of the fetus within a few weeks of pregnancy. NIPPT relies on the analysis of cell-free fetal DNA (cffDNA) found in the maternal bloodstream. However, the abundance of maternal DNA presents a significant challenge in detecting fetal DNA. As a result, research has focused on improving methods for isolating or enriching fetal DNA and, specifically in the context of forensic genetics, on the development of suitable genetic markers. The use of Single Nucleotide Polymorphisms (SNPs) along with novel compound markers or composite multiplexes, has shown promising results. Despite significant advances, partly driven by the increased use of Massive Parallel Sequencing (MPS), challenges remain in validating markers-based NIPPT assays for forensic casework. Further studies are required to enhance the sensitivity of these tests, particularly during the early stages of pregnancy, such as the first trimester. Additionally, improving and standardizing statistical frameworks for result evaluation and interpretation is essential to ensure compatibility with forensic standards.

The Art (and Science) of Individualized Selection of Non-Invasive Prenatal Screening (NIPS)

Non-invasive prenatal screening (NIPS), utilizing cell-free fetal DNA (cffDNA), has revolutionized prenatal care, transitioning from primarily detecting common fetal aneuploidies to encompassing detection of an increasingly broader spectrum of autosomal dominant and recessive conditions. This Commentary delves into the evolution of NIPS, emphasizes the importance of individualized selection of NIPS strategies based on specific clinical scenarios including patient characteristics, and explores its applications beyond aneuploidy screening. The optimal NIPS strategy should be carefully selected based on individual patient factors, including the specific clinical indications, maternal characteristics such as BMI, medical history, medication use, history of previous pregnancies, fetal characteristics such as multiple gestation or suspected anomalies, and the available NIPS technologies. There are also considerations in choosing between MPSS and SNP-based NIPS based cfDNA screening technologies. NIPS is a screening test; hence, diagnostic testing remains crucial for confirmation of any abnormal screening results. Notwithstanding, NIPS has significantly transformed prenatal care, offering valuable insights into fetal health and enabling earlier identification of potential risks. By carefully considering individual patient factors and selecting the most appropriate NIPS strategy, clinicians have the ability to maximize the benefits of this innovative technology while minimizing potential limitations. Continued research and technological advancements will further refine NIPS and expand its applications in the future.

Circulating tumor DNA in colorectal cancer: biology, methods and applications

In the practice of colorectal cancer (CRC), traditional tumor tissue analysis is limited by intratumoral and intertumoral heterogeneity and its invasive nature. Circulating tumor DNA (ctDNA) analysis, a promising liquid biopsy approach, has been increasingly explored in clinical studies. Biologically, ctDNA is characterized by tumor-specific diversity and rapid clearance from circulation, enabling real-time, dynamic, and repeatable assessments. Technologically, PCR- and NGS-based downstream analysis methods have been developed and validated. However, variables in pre-analytical and analytical procedures underscores the need for standardized protocols. Compared with clinicopathology-based risk stratification, ctDNA-based molecular residual disease detection has demonstrated significant potential in guiding treatment decisions. Qualitative and quantitative changes in ctDNA have also shown predictive and prognostic value during neoadjuvant or adjuvant treatment, as well as in later-line treatment for metastatic CRC. Specific molecular aberrations in ctDNA can not only assist in identifying candidates for targeted therapies but also reveal resistance mechanisms. Additionally, emerging research is exploring the potential of ctDNA in early cancer detection. Overall, as a novel biomarker, ctDNA holds substantial promise in advancing clinical practice. This review focuses on the biological characteristics, pre-analytical variables, and downstream analysis methods of ctDNA and summarizes its role across various clinical scenarios in CRC.

Phenotypic heterogeneity and tumor immune microenvironment directed therapeutic strategies in pancreatic ductal adenocarcinoma

Pancreatic cancer is an aggressive tumor with high metastatic potential which leads to decreased survival rate and resistance to chemotherapy and immunotherapy. Nearly 90% of pancreatic cancer comprises pancreatic ductal adenocarcinoma (PDAC). About 80% of diagnoses takes place at the advanced metastatic stage when it is unresectable, which renders chemotherapy regimens ineffective. There is also a dearth of specific biomarkers for early-stage detection. Advances in next generation sequencing and single cell profiling have identified molecular alterations and signatures that play a role in PDAC progression and subtype plasticity. Most chemotherapy regimens have shown only modest survival benefits, and therefore, translational approaches for immunotherapies and combination therapies are urgently required. In this review, we have examined the immunosuppressive and dense stromal network of tumor immune microenvironment with various metabolic and transcriptional changes that underlie the pro-tumorigenic properties in PDAC in terms of phenotypic heterogeneity, plasticity and subtype co-existence. Moreover, the stromal heterogeneity as well as genetic and epigenetic changes that impact PDAC development is discussed. We also review the PDAC interaction with sequestered cellular and humoral components present in the tumor immune microenvironment that modify the outcome of chemotherapy and radiation therapy. Finally, we discuss different therapeutic interventions targeting the tumor immune microenvironment aimed at better prognosis and improved survival in PDAC.

Circulating tumor DNA to monitor treatment response in solid tumors and advance precision oncology

Circulating tumor DNA (ctDNA) has emerged as a dynamic biomarker in cancer, as evidenced by its increasing integration into clinical practice. Carrying tumor specific characteristics, ctDNA can be used to inform treatment selection, monitor response, and identify drug resistance. In this review, we provide a comprehensive, up-to-date summary of ctDNA in monitoring treatment response with a focus on lung, colorectal, and breast cancers, and discuss current challenges and future directions.

Plasma Mycobacterium tuberculosis cell-free DNA assay: a diagnostic tool for tuberculosis lymphadenitis

BACKGROUND

Bacterial confirmation in suspected tuberculosis lymphadenitis patients is challenging. This study evaluates plasma Mycobacterium tuberculosis cell-free DNA as a diagnostic tool for tuberculosis lymphadenitis.

METHODS

A quantitative PCR assay targeting IS6110, IS1081, and cyp141 genes was performed on plasma samples. The study included 95 tuberculosis lymphadenitis patients and 60 controls. Sensitivity of the plasma Mycobacterium tuberculosis cell-free DNA assay was assessed against fine needle aspiration GeneXpert Ultra, fine needle aspiration culture, and fine needle aspiration cytology, while specificity was determined using control groups.

RESULTS

Of the tuberculosis lymphadenitis cases, 71 (74.7%) were bacteriologically confirmed, and 24 (25.3%) were probable. In the control group, 50% had latent tuberculosis infection. The Mycobacterium tuberculosis cell-free DNA assay, targeting three genes, had an overall sensitivity of 65.3%, increasing to 70.4% for confirmed cases and 50% for probable cases, with specificity of 91.1%. Sensitivities for specific gene combinations were 62.1% for IS6110 and IS1081, 54.7% for IS6110 and cyp141, and 55.8% for IS1081 and cyp141. For individual genes, IS6110 showed 49.4% sensitivity (specificity: 93.3%), IS1081 had 51.6% (specificity: 96.0%), and cyp141 showed 28.4% (specificity: 96.7%). Combining positive results from all three genes in the cell-free DNA assay with fine needle aspiration culture and GeneXpert Ultra improved sensitivity to 76.8% and 85.3%, respectively.

CONCLUSION

This study demonstrated that Mycobacterium tuberculosis cell-free DNA can be detected in the plasma of over half of tuberculosis lymphadenitis patients. The plasma Mycobacterium tuberculosis cell-free DNA assay could serve as a valuable, less-invasive complement to existing fine needle aspiration diagnostics.

Beyond traditional biopsies: the emerging role of ctDNA and MRD on breast cancer diagnosis and treatment

Breast cancer management has traditionally relied on tissue biopsies and imaging, which offer limited insights into the disease. However, the discovery of circulating tumor DNA (ctDNA) and minimal residual disease (MRD) detection has revolutionized our approach to breast cancer. ctDNA, which is fragmented tumor DNA found in the bloodstream, provides a minimally invasive way to understand the tumor's genomic landscape, revealing heterogeneity and critical mutations that biopsies may miss. MRD, which indicates cancer cells that remain after treatment, can now be detected using ctDNA and other advanced methods, improving our ability to predict disease recurrence. This allows for personalized adjuvant therapies based on individual MRD levels, avoiding unnecessary treatments for patients with low MRD. This review discusses how ctDNA and MRD represent a paradigm shift towards personalized, genomically guided cancer care, which has the potential to significantly improve patient outcomes in breast cancer.

Application of Digital Polymerase Chain Reaction (dPCR) in Non-Invasive Prenatal Testing (NIPT)

This article reviews the current applications of the digital polymerase chain reaction (dPCR) in non-invasive prenatal testing (NIPT) and explores its potential to complement or surpass the capabilities of Next-Generation Sequencing (NGS) in prenatal testing. The growing incidence of genetic disorders in maternal-fetal medicine has intensified the demand for precise and accessible NIPT options, which aim to minimize the need for invasive prenatal diagnostic procedures. Cell-free fetal DNA (cffDNA), the core analyte in NIPT, is influenced by numerous factors such as maternal DNA contamination, placental health, and fragment degradation. dPCR, with its inherent precision and ability to detect low-abundance targets, demonstrates robustness against these interferences. Although NGS remains the gold standard due to its comprehensive diagnostic capabilities, its high costs limit widespread use, particularly in resource-limited settings. In contrast, dPCR provides comparable accuracy with lower complexity and expense, making it a promising alternative for prenatal testing.

Computational Modeling for Circulating Cell-Free DNA in Clinical Oncology

PURPOSE

Liquid biopsy, specifically circulating cell-free DNA (cfDNA), has emerged as a powerful tool for cancer early diagnosis, prognosis, and treatment monitoring over a wide range of cancer types. Computational modeling (CM) of cfDNA data is essential to harness its full potential for real-time, noninvasive insights into tumor biology, enhancing clinical decision making.

DESIGN

This work reviews CM-cfDNA methods applied to clinical oncology, emphasizing both machine learning (ML) techniques and mechanistic approaches. The latter integrate biological principles, enabling a deeper understanding of cfDNA dynamics and its relationship with tumor evolution.

RESULTS

Key findings highlight the effectiveness of CM-cfDNA approaches in improving diagnostic accuracy, identifying prognostic markers, and predicting therapeutic outcomes. ML models integrating cfDNA concentration, fragmentation patterns, and mutation detection achieve high sensitivity and specificity for early cancer detection. Mechanistic models describe cfDNA kinetics, linking them to tumor growth and response to treatment, for example, immune checkpoint inhibitors. Longitudinal data and advanced statistical constructs further refine these models for quantification of interindividual and intraindividual variability.

CONCLUSION

CM-cfDNA represents a pivotal advancement in precision oncology. It bridges the gap between extensive cfDNA data and actionable clinical insights, supporting its integration into routine cancer care. Future efforts should focus on standardizing protocols, validating models across populations, and exploring hybrid approaches combining ML with mechanistic modeling to improve biological understanding.

DNA methylation biomarkers of intellectual/developmental disability across the lifespan

Epigenetic mechanisms, including DNA methylation, act at the interface of genes and environment by allowing a static genome to respond and adapt to a dynamic environment during the lifespan of an individual. Genome-wide DNA methylation analyses on a wide range of human biospecimens are beginning to identify epigenetic biomarkers that can predict risk of intellectual/developmental disabilities (IDD). DNA methylation-based epigenetic signatures are becoming clinically useful in categorizing benign from pathogenic genetic variants following exome sequencing. While DNA methylation marks differ by tissue source, recent studies have shown that accessible perinatal tissues, such as placenta, cord blood, newborn blood spots, and cell free DNA may serve as accessible surrogate tissues for testing epigenetic biomarkers relevant to understanding genetic, environmental, and gene by environment interactions on the developing brain. These DNA methylation signatures may also provide important information about the biological pathways that become dysregulated prior to disease progression that could be used to develop early pharmacological interventions. Future applications could involve preventative screenings using DNA methylation biomarkers during pregnancy or the newborn period for IDDs and other neurodevelopmental disorders. DNA methylation biomarkers in adolescence and adulthood are also likely to be clinically useful for tracking biological aging or co-occurring health conditions that develop across the lifespan. In conclusion, DNA methylation biomarkers are expected to become more common in clinical diagnoses of IDD, to improve understanding of complex IDD etiologies, to improve endpoints for clinical trials, and to monitor potential health concerns for individuals with IDD as they age.

Diagnostic performance of metagenomic next-generation sequencing among hematological malignancy patients with bloodstream infections after antimicrobial therapy

BACKGROUND

Metagenomic next-generation sequencing (mNGS) is an effective method for detecting pathogenic pathogens of bloodstream infection (BSI). However, there is no consensus on whether the use of antibiotics affects the diagnostic performance of mNGS. We conducted a prospective clinical study aiming to evaluate the effect of antimicrobial treatment on mNGS.

METHODS

Blood samples were collected for mNGS testing within 24 h of culture-confirmed with BSI, with re-examination conducted every 2-3 days.

RESULTS

A total of 38 patients with BSI were enrolled. The mNGS positive (mNGS-pos) rate declined sharply after the use of antibiotics, with only 17 (44.78%) patients remaining mNGS-pos while the rest were mNGS negative (mNGS-neg). The median duration of pathogen identification was significantly longer for mNGS compared to blood culture (BC) (4 days vs 1 days; P < 0.0001). A positivity duration of ≥ 3 days was an independent risk factor of septic shock (OR, 20.671; 95% CI, 1.958-218.190; P = 0.012). Patients with mNGS-pos and mNGS-neg differed by the median duration of fever (6 days vs 3 days; P = 0.038), rates of drug resistance (35.3% vs 4.8%; P = 0.017), rates of septic shock (47.1% vs 14.3%; P = 0.029), and 28-day mortality (29.4% vs 4.8%; P = 0.041).

CONCLUSIONS

The antimicrobial treatment will greatly reduce the positive rate of mNGS. The duration of mNGS is significantly longer than that of BC. The prolonged duration of mNGS suggests an increased risk of septic shock and could be identified as a high-risk factor of adverse infection outcome, requiring more aggressive anti-infective treatment measures.

Analysis of a cell-free DNA-based cancer screening cohort links fragmentomic profiles, nuclease levels, and plasma DNA concentrations

The concentration of circulating cell-free DNA (cfDNA) in plasma is an important determinant of the robustness of liquid biopsies. However, biological mechanisms that lead to inter-individual differences in cfDNA concentrations remain unexplored. The concentration of plasma cfDNA is governed by an interplay between its release and clearance. We hypothesized that cfDNA clearance by nucleases might be one mechanism that contributes toward inter-individual variations in cfDNA concentrations. We performed fragmentomic analysis of the plasma cfDNA from 862 healthy individuals, with a cfDNA concentration range of 1.61-41.01 ng/mL. We observed an increase in large DNA fragments (231-600 bp), a decreased frequencies of shorter DNA fragments (20-160 bp), and an increased frequency of G-end motifs with increasing cfDNA concentrations. End motif deconvolution analysis revealed a decreased contribution of DNASE1L3 and DFFB in subjects with higher cfDNA concentration. The five subjects with the highest plasma DNA concentration (top 0.58%) had aberrantly decreased levels of DNASE1L3 protein in plasma. The cfDNA concentration could be inferred from the fragmentomic profile through machine learning and was well correlated to the measured cfDNA concentration. Such an approach could infer the fractional DNA concentration from particular tissue types, such as the fetal and tumor fraction. This work shows that individuals with different cfDNA concentrations are associated with characteristic fragmentomic patterns of the cfDNA pool and that nuclease-mediated clearance of DNA is a key parameter that affects cfDNA concentration. Understanding these mechanisms has facilitated the enhanced measurement of cfDNA species of clinical interest, including circulating fetal and tumor DNA.

Dynamics and Half-Life of Cell-Free DNA After Exercise: Insights from a Fragment Size-Specific Measurement Approach

Background: Cell-free DNA (cfDNA) is present in healthy individuals but is elevated in those undergoing physical exertion, trauma, sepsis, and certain cancers. Maintaining cfDNA concentrations is vital for immune homeostasis and preventing inflammatory responses. Understanding cfDNA release and clearance is essential for using cfDNA as a biomarker in clinical diagnostics. We focused on the fragment size of cfDNA and investigated cfDNA dynamics and half-life, particularly the 100-250 base pair fragments. Methods: Healthy, adult men (n = 5; age 40 ± 4.1 years) were subjected to a 30 min treadmill exercise. Blood samples were collected at 0, 5, 10, 15, 30, and 60 min post-exercise using PAXgene® Blood ccfDNA tubes to stabilize and prevent nuclease-mediated cfDNA degradation and minimize genomic DNA contamination risk. The cfDNA concentration was measured using an electrophoresis-based technique (4150 TapeStation system) to quantify the concentration based on cfDNA fragment size. Results: The results showed a cfDNA half-life of 24.2 min, with a transient increase in 100-250 base pair cfDNA fragments post-exercise, likely due to nuclease activity. These levels rapidly reverted to the baseline within an hour. Conclusions: The rapid clearance of cfDNA underscores its potential as a biomarker for real-time disease monitoring and the evaluation of treatment efficacy. This study is expected to standardize cfDNA investigations, enhancing diagnosis and treatment monitoring across various disease conditions.

"Aging Clocks" Based on Cell-Free DNA

Aging is associated with systemic changes in the physiological and molecular parameters of the body. These changes are referred to as biomarkers of aging. Statistical models that link changes in individual biomarkers to biological age are called aging clocks. These tools facilitate a comprehensive evaluation of bodily health and permit the quantitative determination of the rate of aging. A particularly promising area for the development of aging clocks is the analysis of cell-free DNA (cfDNA), which is present in the blood and contains numerous potential biomarkers. This review explores in detail the fragmentomics, topology, and epigenetic landscape of cfDNA as possible biomarkers of aging. The review further underscores the potential of leveraging single-molecule sequencing of cfDNA in conjunction with long-read technologies to simultaneously profile multiple biomarkers, a strategy that could lead to the development of more precise aging clocks.

Targeted liquid biopsy for brain tumors

Cerebrospinal fluid (CSF) is a promising source of molecular biomarkers in the detection and monitoring of brain malignancies. Unlike peripheral blood, where biomarker detection is hindered by the blood-brain barrier and the complex nature of biofluids, CSF offers a more direct and enriched source of tumor-derived markers, including circulating tumor DNA (ctDNA), microRNA (miRNA), proteins, and extracellular vesicles (EVs). These biomarkers, originating from brain tumor cells, are often more concentrated in CSF than in peripheral blood due to the proximity of CSF to the central nervous system (CNS). The presence of ctDNA in CSF is notably higher than in plasma, making CSF an advantageous medium for liquid biopsy in brain tumor patients. Traditional liquid biopsy approaches relying on peripheral venous blood samples often face challenges in detecting low concentrations of tumor-derived biomarkers. The direct contact of CSF with the CNS minimizes background noise, potentially enhancing the accuracy and sensitivity of diagnostic assays. Despite the barriers posed by the blood-brain barrier and other physiological factors that limit biomarker levels in the systemic circulation, CSF's unique position within the CNS allows for more effective biomarker collection. While peripheral blood remains the standard medium for liquid biopsy in oncology, the proximity of CSF to brain tumors suggests it may offer superior diagnostic capabilities. Emerging evidence from non-CNS malignancies indicates that collecting biofluids closer to the tumor site can significantly improve biomarker detection. Although this approach has been well-documented in other solid tumors, its application to CNS malignancies remains underexplored. This study hypothesizes that targeted blood sampling from CNS tumor-draining veins could similarly enhance biomarker detection, thereby increasing the sensitivity and efficacy of liquid biopsy techniques in diagnosing and monitoring brain malignancies.

Cell-free placental DNA: What do we really know?

Cell-free placental DNA (cfpDNA) is present in maternal circulation during gestation. CfpDNA carries great potential as a research and clinical tool as it provides a means to investigate the placental (epi)genome across gestation, which previously required invasive placenta sampling procedures. CfpDNA has been widely implemented in the clinical setting for noninvasive prenatal testing (NIPT). Despite this, the basic biology of cfpDNA remains poorly understood, limiting the research and clinical utility of cfpDNA. This review will examine the current knowledge of cfpDNA, including origins and molecular characteristics, highlight gaps in knowledge, and discuss future research directions.

Cell-Free DNA in Hematologic Malignancies

Liquid biopsy techniques using cell-free DNA (cfDNA) play an increasingly important role in the characterization and surveillance of solid tumors. For blood cancers, molecular response assessment techniques using circulating malignant cells or bone marrow aspirates are well established in clinical care. However, cfDNA has an emerging role in hematology as well, with the opportunity for disease assessment and quantification independent of circulating disease burden or invasive biopsies. In this review, we discuss key technologies and clinical data for the utilization of cfDNA in lymphomas, myeloma, and leukemias.

Nucleic acid liquid biopsies in cardiovascular disease: Cell-free DNA liquid biopsies in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of death worldwide, and despite treatment efforts, cardiovascular function cannot always be restored, and progression of disease be prevented. Critical insights are oftentimes based on tissue samples. Current knowledge of tissue pathology typically relies on invasive biopsies or postmortem samples. Liquid biopsies, which assess circulating mediators to deduce the histology and pathology of distant tissues, have been advancing rapidly in cancer research and offer a promising approach to be translated to the understanding and treatment of CVD. The widely understood elevations in cell-free DNA during acute and chronic cardiovascular conditions, associate with disease, severity, and offer prognostic value. The role of neutrophil extracellular traps (NETs) and circulating nucleases in thrombosis provide a solid rationale for liquid biopsies in CVD. cfDNA originates from various tissue types and cellular sources, including mitochondria and nuclei, and can be used to trace cell and tissue type lineage, as well as to gain insight into the activation status of cells. This article discusses the origin, structure, and potential utility of cfDNA, offering a deeper and less invasive approach for the understanding of the complexities of CVD.

The detection, biological function, and liquid biopsy application of extracellular vesicle-associated DNA

Cell-derived extracellular vesicles (EVs), which carry diverse biomolecules such as nucleic acids, proteins, metabolites, and lipids reflecting their cell of origin, are released under both physiological and pathological conditions. EVs have been demonstrated to mediate cell-to-cell communication and serve as biomarkers. EV-associated DNA (EV-DNA) comprises genomic and mitochondrial DNA (i.e., gDNA and mtDNA) fragments. Some studies have revealed that EV-DNA can represent the full nuclear genome and mitochondrial genome of parental cells. Furthermore, DNA fragments loaded into EVs are stable and can be transferred to recipient cells to regulate their biological functions. In this review, we summarized and discussed EV-DNA research advances with an emphasis on EV-DNA detection at the population-EV and single-EV levels, gene transfer-associated biological functions, and clinical applications as biomarkers for disease liquid biopsy. We hope that this review will provide potential directions or guidance for future EV-DNA investigations.

Placental somatic mutation in human stillbirth and live birth: A pilot case-control study of paired placental, fetal, and maternal whole genomes

INTRODUCTION

A high frequency of single nucleotide somatic mutations in the placenta has been recently described, but its relationship to placental dysfunction is unknown.

METHODS

We performed a pilot case-control study using paired fetal, maternal, and placental samples collected from healthy live birth controls (n = 10), live births with fetal growth restriction (FGR) due to placental insufficiency (n = 7), and stillbirths with FGR and placental insufficiency (n = 11). We quantified single nucleotide and structural somatic variants using bulk whole genome sequencing (30-60X coverage) in four biopsies from each placenta. We also assessed their association with clinical and histological evidence of placental dysfunction.

RESULTS

Seventeen pregnancies had sufficiently high-quality placental, fetal, and maternal DNA for analysis. Each placenta had a median of 473 variants (range 111-870), with 95 % arising in just one biopsy within each placenta. In controls, live births with FGR, and stillbirths, the median variant counts per placenta were 514 (IQR 381-779), 582 (450-735), and 338 (245-441), respectively. After adjusting for depth of sequencing coverage and gestational age at birth, the somatic mutation burden was similar between groups (FGR live births vs. controls, adjusted diff. 59, 95 % CI -218 to +336; stillbirths vs controls, adjusted diff. -34, -351 to +419), and with no association with placental dysfunction (p = 0.7).

DISCUSSION

We confirmed the high prevalence of somatic mutation in the human placenta and conclude that the placenta is highly clonal. We were not able to identify any relationship between somatic mutation burden and clinical or histologic placental insufficiency.

Multibiomarker panels in liquid biopsy for early detection of pancreatic cancer - a comprehensive review

Pancreatic ductal adenocarcinoma (PDAC) is frequently detected in late stages, which leads to limited therapeutic options and a dismal overall survival rate. To date, no robust method for the detection of early-stage PDAC that can be used for targeted screening approaches is available. Liquid biopsy allows the minimally invasive collection of body fluids (typically peripheral blood) and the subsequent analysis of circulating tumor cells or tumor-associated molecules such as nucleic acids, proteins, or metabolites that may be useful for the early diagnosis of PDAC. Single biomarkers may lack sensitivity and/or specificity to reliably detect PDAC, while combinations of these circulating biomarkers in multimarker panels may improve the sensitivity and specificity of blood test-based diagnosis. In this narrative review, we present an overview of different liquid biopsy biomarkers for the early diagnosis of PDAC and discuss the validity of multimarker panels.

Cell-free DNA test for fetal chromosomal abnormalities in multiple pregnancies

INTRODUCTION

This study aimed to report the screening performance of cell-free DNA (cfDNA) testing for chromosomal abnormalities in twins, triplets, and vanishing twin pregnancies.

MATERIAL AND METHODS

Data were obtained from pregnant women with a multiple pregnancy or a vanishing twin pregnancy at ≥10 weeks' gestation who requested self-financed cfDNA testing between May 2015 and December 2021. Those that had positive screening results had diagnostic confirmatory procedures after counseling and consent. The performance of screening of the cfDNA test was determined by calculating confirmation rate and combined false-positive rate (cFPR).

RESULTS

Data from 292 women were included after exclusion of those lost to follow-up, with no-result on cfDNA testing, or had reductions. Of the 292 pregnancies, 10 (3.4%) were triplets, including no cases of trisomy 21 and trisomy 18; 249 (85.3%) were twins, including 3 cases of trisomy 21 and no cases of trisomy 18 and 13; and 33 (11.3%) were vanishing twins, including 3 cases of trisomy 21 and 1 case of trisomy 18. The median (IQR) maternal age was 34 years (31-37). For triplet pregnancies, the initial no-result rate was 10.3% (95% confidence interval [CI] 3.6-26.4), all with results after redraw. For twin pregnancies, the initial no-result rate was 12.9% (95% CI 9.6-17.0), and the no-result rate after redraw was 1.6% (95% CI 0.7-3.6). For vanishing twins, there were no cases with no-result. All triplets had low-risk cfDNA results. The confirmation rate for trisomy 21 was 100% with a FPR at 0% due to the small number of positive cases for twins. For vanishing twins, one high-risk case for trisomy 21 and the only high-risk case for trisomy 18 were confirmed with a cFPR of 8.3% (n = 2/24; 95% CI 2.3-25.9).

CONCLUSIONS

cfDNA testing in twin pregnancies has sufficient screening performance for trisomy 21 but the number of affected cases for other conditions is limited to draw any meaningful conclusion. The use of cfDNA testing in triplet pregnancies and vanishing twins remains an area for further research.

Emergency Myelopoiesis Distinguishes Multisystem Inflammatory Syndrome in Children From Pediatric Severe Coronavirus Disease 2019

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) is a hyperinflammatory condition caused by recent infection with severe acute respiratory syndrome coronavirus 2, but the underlying immunological mechanisms driving this distinct syndrome are unknown.

METHODS

We utilized high-dimensional flow cytometry, cell-free (cf) DNA, and cytokine and chemokine profiling to identify mechanisms of critical illness distinguishing MIS-C from severe acute coronavirus disease 2019 (SAC).

RESULTS

Compared to SAC, MIS-C patients demonstrated profound innate immune cell death and features of emergency myelopoiesis (EM), an understudied phenomenon observed in severe inflammation. EM signatures were characterized by fewer mature myeloid cells in the periphery and decreased expression of HLA-DR and CD86 on antigen-presenting cells. Interleukin 27 (IL-27), a cytokine known to drive hematopoietic stem cells toward EM, was increased in MIS-C, and correlated with immature cell signatures in MIS-C. Upon recovery, EM signatures decreased and IL-27 plasma levels returned to normal levels. Despite profound lymphopenia, we report a lack of cfDNA released by adaptive immune cells and increased CCR7 expression on T cells indicative of egress out of peripheral blood.

CONCLUSIONS

Immune cell signatures of EM combined with elevated innate immune cell-derived cfDNA levels distinguish MIS-C from SAC in children and provide mechanistic insight into dysregulated immunity contributing toward MIS-C, offering potential diagnostic and therapeutic targets.

Comprehensive Recommendations for the Clinical Management of Pregnant Women With Noninvasive Prenatal Test Results Suspicious of a Maternal Malignancy

In this article, we defined comprehensive recommendations for the clinical follow-up of pregnant women with a malignancy-suspicious NIPT result, on the basis of the vast experience with population-based NIPT screening programs in two European countries complemented with published large data sets. These recommendations provide a tool for classifying NIPT results as malignancy-suspicious, and guide health care professionals in structured clinical decision making for the diagnostic process of pregnant women who receive such a malignancy-suspicious NIPT result.

Circulating free DNA as a diagnostic marker for echinococcosis: a systematic review and meta-analysis

Introduction

Echinococcosis is a chronic zoonotic disease caused by tapeworms of the genus Echinococcus. The World Health Organization (WHO) has identified encapsulated disease as one of 17 neglected diseases to be controlled or eliminated by 2050. There is no accurate, early, non-invasive molecular diagnostic method to detect echinococcosis. The feasibility of circulating free DNA as a diagnostic method for echinococcosis has yielded inconclusive results in a number of published studies. However, there has been no systematic evaluation to date assessing the overall performance of these assays. We report here the first meta-analysis assessing the diagnostic accuracy of cfDNA in plasma, serum, and urine for echinococcosis.

Methods

We systematically searched PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and WeiPu databases up to 17 January 2024, for relevant studies. All analyses were performed using RevMan 5.3, Meta-DiSc 1.4, Stata 17.0, and R 4.3.1 software. The sensitivity, specificity, and other accuracy indicators of circulating free DNA for the diagnosis of echinococcosis were summarized. Subgroup analyses and meta-regression were performed to identify sources of heterogeneity.

Results

A total of 7 studies included 218 patients with echinococcosis and 214 controls (156 healthy controls, 32 other disease controls (non-hydatid patients), and 26 non-study-targeted echinococcosis controls were included). Summary estimates of the diagnostic accuracy of cfDNA in the diagnosis of echinococcosis were as follows: sensitivity (SEN) of 0.51 (95% CI: 0.45-0.56); specificity (SPE) of 0.99 (95% CI: 0.97-0.99); positive likelihood ratio (PLR) of 11.82 (95% CI: 6.74-20.74); negative likelihood ratio (NLR) of 0.57 (95% CI: 0.41-0.80); diagnostic ratio (DOR) of 36.63 (95% CI: 13.75-97.59); and area under the curve (AUC) value of 0.98 (95% CI: 0.96-1.00).

Conclusion

Existing evidence indicates that the combined specificity of circulating cfDNA for echinococcosis is high. However, the combined sensitivity performance is unsatisfactory due to significant inter-study heterogeneity. To strengthen the validity and accuracy of our findings, further large-scale prospective studies are required.Systematic review registrationThe systematic review was registered in the International Prospective Register of Systematic Reviews PROSPERO [CRD42023454158]. https://www.crd.york.ac.uk/PROSPERO/.

Liquid Biopsy Based on Cell-Free DNA and RNA

This review delves into the rapidly evolving landscape of liquid biopsy technologies based on cell-free DNA (cfDNA) and cell-free RNA (cfRNA) and their increasingly prominent role in precision medicine. With the advent of high-throughput DNA sequencing, the use of cfDNA and cfRNA has revolutionized noninvasive clinical testing. Here, we explore the physical characteristics of cfDNA and cfRNA, present an overview of the essential engineering tools used by the field, and highlight clinical applications, including noninvasive prenatal testing, cancer testing, organ transplantation surveillance, and infectious disease testing. Finally, we discuss emerging technologies and the broadening scope of liquid biopsies to new areas of diagnostic medicine.

Trisomy 21 with Maternally Inherited Balanced Translocation (15q;22q) in a Female Fetus: A Rare Case of Probable Interchromosomal Effect

Chromosomal rearrangements can interfere with the disjunction and segregation of other chromosome pairs not involved in the rearrangements, promoting the occurrence of numerical abnormalities in resulting gametes and predisposition to trisomy in offspring. This phenomenon of interference is known as the interchromosomal effect (ICE). Here we report a prenatal case potentially generated by ICE. The first-trimester screening ultrasound of the pregnant woman was normal, but the NIPT indicated a high risk for three copies of chromosome 21, thus suspecting trisomy 21 (T21). After a comprehensive clinical evaluation and genetic counseling, the couple decided to undergo amniocentesis. The prenatal karyotype confirmed T21 but also showed a balanced translocation between the long arm of chromosome 15 (q22) and the long arm of chromosome 22. The parents' karyotypes also showed that the mother had the 15;22 translocation. We reviewed T21 screening methods, and we performed a literature review on ICE, a generally overlooked phenomenon. We observed that ours is the first report of a prenatal case potentially due to ICE derived from the mother. The recurrence risk of aneuploidy in the offspring of translocated individuals is likely slightly increased, but it is not possible to estimate to what extent. In addition to supporting observations, there are still open questions such as, how frequent is ICE? How much is the aneuploidy risk altered by ICE?

Advancements of non-invasive prenatal testing: the role of obstetricians

Since its debut in 2011, Non-Invasive Prenatal Testing (NIPT) has continually demonstrated its effectiveness in detecting an expanding number of diseases. NIPT offers a less invasive approach to prenatal chromosomal disease screening, providing prospective parents with vital information to better prepare for their potential pregnancy outcomes. NIPT was primarily designed for screening trisomy 13, 18, and 21. However, its scope has since broadened to encompass microdeletions and autosomal dominant monogenic diseases. Conversely, the normalization of NIPT can have unintended consequences. Some patients opt for NIPT without any medical indications, driven by a desire to remain cautious. This over-screening for chromosomal abnormalities can exacerbate pregnancy-related anxiety, as individuals might feel pressured into taking the test unnecessarily. While NIPT can be highly successful when conducted correctly, it is not infallible, and obstetricians play a crucial role in managing patient expectations. This includes providing genetic counseling to individuals with relevant genetic information regarding their personal and family histories. In the context of NIPT, a bioinformatics analysis is performed on a cell-free DNA (cfDNA) sample extracted from the mother's placenta to determine the fetal fraction (FF). This FF measurement is vital for quality control and ensuring statistical confidence in the test results. Raising awareness among clinicians about the significance of FF enhances patient care and alleviate concerns about the possibility of failed NIPT. This paper aims to explore the ongoing debates and more specifically the significance and pitfalls of NIPT on a psychosocial and ethical scale, all while highlighting the importance of genetic counseling.

Principles of digital sequencing using unique molecular identifiers

Massively parallel sequencing technologies have long been used in both basic research and clinical routine. The recent introduction of digital sequencing has made previously challenging applications possible by significantly improving sensitivity and specificity to now allow detection of rare sequence variants, even at single molecule level. Digital sequencing utilizes unique molecular identifiers (UMIs) to minimize sequencing-induced errors and quantification biases. Here, we discuss the principles of UMIs and how they are used in digital sequencing. We outline the properties of different UMI types and the consequences of various UMI approaches in relation to experimental protocols and bioinformatics. Finally, we describe how digital sequencing can be applied in specific research fields, focusing on cancer management where it can be used in screening of asymptomatic individuals, diagnosis, treatment prediction, prognostication, monitoring treatment efficacy and early detection of treatment resistance as well as relapse.

Cell‑free fetal DNA at 11‑13 weeks of gestation is not altered in complicated pregnancies

Non-invasive maternal cell-free fetal DNA (cffDNA) is a promising biomarker for screening common genetic syndromes. Alterations in the expression levels of cffDNA in the maternal circulation have been demonstrated in abnormal pregnancies. However, the results are conflicting. The present study aimed to investigate whether cffDNA levels are associated with pregnancy complications. The study group comprised pregnant women who presented with pregnancy complications, such as preterm birth, gestational hypertension, intrauterine growth retardation, gestational diabetes, polyhydramnios, oligohydramnios, vaginal bleeding and placental abruption. The control group comprised women who had a normal pregnancy course. Blood samples were obtained from 500 pregnant women between 11-13 weeks of gestation. cffDNA was amplified, sequenced and analyzed using the next-generation aneuploidy test of a Panorama-Natera kit. Nuchal translucency (NT) thickness as well as pregnancy associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG) levels were also assessed. Statistical analysis was performed in 494 out of the 500 samples collected with SPSS v.26 using non-parametric methods. The parameters were normalized by the multiples of median (MoM) method. The expression levels of PAPP-A, β-hCG, and the NT mean MoM values were significantly different between the study and control groups (P=0.005, P<0.001 and P=0.007, respectively). However, the expression levels of cffDNA and the mean MoM values were not significantly different between these two groups (P=0.687). The findings of the present study support the conclusion that cffDNA expression is not altered in a series of pregnancy complications. The prognostic value of cffDNA in predicting adverse pregnancy outcomes requires further investigation.

Are fetal microchimerism and circulating fetal extracellular vesicles important links between spontaneous preterm delivery and maternal cardiovascular disease risk?

Trafficking and persistence of fetal microchimeric cells (fMCs) and circulating extracellular vesicles (EVs) have been observed in animals and humans, but their consequences in the maternal body and their mechanistic contributions to maternal physiology and pathophysiology are not yet fully defined. Fetal cells and EVs may help remodel maternal organs after pregnancy-associated changes, but the cell types and EV cargos reaching the mother in preterm pregnancies after exposure to various risk factors can be distinct from term pregnancies. As preterm delivery-associated maternal complications are rising, revisiting this topic and formulating scientific questions for future research to reduce the risk of maternal morbidities are timely. Epidemiological studies report maternal cardiovascular risk as one of the major complications after preterm delivery. This paper suggests a potential link between fMCs and circulating EVs and adverse maternal cardiovascular outcomes post-pregnancies, the underlying mechanisms, consequences, and methods for and how this link might be assessed.

Liquid biopsy for gastric cancer: Techniques, applications, and future directions

After the study of circulating tumor cells in blood through liquid biopsy (LB), this technique has evolved to encompass the analysis of multiple materials originating from the tumor, such as nucleic acids, extracellular vesicles, tumor-educated platelets, and other metabolites. Additionally, research has extended to include the examination of samples other than blood or plasma, such as saliva, gastric juice, urine, or stool. LB techniques are diverse, intricate, and variable. They must be highly sensitive, and pre-analytical, patient, and tumor-related factors significantly influence the detection threshold, diagnostic method selection, and potential results. Consequently, the implementation of LB in clinical practice still faces several challenges. The potential applications of LB range from early cancer detection to guiding targeted therapy or immunotherapy in both early and advanced cancer cases, monitoring treatment response, early identification of relapses, or assessing patient risk. On the other hand, gastric cancer (GC) is a disease often diagnosed at advanced stages. Despite recent advances in molecular understanding, the currently available treatment options have not substantially improved the prognosis for many of these patients. The application of LB in GC could be highly valuable as a non-invasive method for early diagnosis and for enhancing the management and outcomes of these patients. In this comprehensive review, from a pathologist's perspective, we provide an overview of the main options available in LB, delve into the fundamental principles of the most studied techniques, explore the potential utility of LB application in the context of GC, and address the obstacles that need to be overcome in the future to make this innovative technique a game-changer in cancer diagnosis and treatment within clinical practice.

What fraction of cellular DNA turnover becomes cfDNA?

Cell-free DNA (cfDNA) tests use small amounts of DNA in the bloodstream as biomarkers. While it is thought that cfDNA is largely released by dying cells, the proportion of dying cells' DNA that reaches the bloodstream is unknown. Here, we integrate estimates of cellular turnover rates to calculate the expected amount of cfDNA. By comparing this to the actual amount of cell type-specific cfDNA, we estimate the proportion of DNA reaching plasma as cfDNA. We demonstrate that <10% of the DNA from dying cells is detectable in plasma, and the ratios of measured to expected cfDNA levels vary a thousand-fold among cell types, often reaching well below 0.1%. The analysis suggests that local clearance, presumably via phagocytosis, takes up most of the dying cells' DNA. Insights into the underlying mechanism may help to understand the physiological significance of cfDNA and improve the sensitivity of liquid biopsies.

Survival outcomes correlate with the level of cell-free circulating DNA in ST-elevation myocardial infarction

Background

Myocardial infarction (MI) can lead to higher cellular damage, making cell-free DNA (cfDNA) a potential biomarker for assessing disease severity. The aim of this study is to evaluate survival predictions using cfDNA measurements and assess its correlation with MI.

Materials and Methods

A direct fluorescence assay was employed to measure cfDNA content in the blood samples of participants. The inclusion criteria included patients who gave informed consent, suffering from ST-elevation myocardial infraction (STEMI) based on established diagnostic criteria (joint ESC/ACC guidelines), between the age of 18 and 80 years old, and had elevated troponin biomarker levels. The study included 150 patients diagnosed with STEMI and 50 healthy volunteers as controls. Serial monitoring of patients was conducted to track their postdisease status. The rate of change of cfDNA was calculated and daily measurements for 7 days were recorded.

Results

Mean levels of cfDNA were found to be 5.93 times higher in patients with STEMI compared to healthy controls, providing clear evidence of a clinical correlation between cfDNA and STEMI. Patients were further categorized based on their survival status within a 90-day period. The study observed a strong predictive relationship between the rate of change of cfDNA during daily measurements and survival outcomes. To assess its predictive capability, a receiver operating characteristics (ROC) curve analysis was performed. The ROC analysis identified an optimal cutoff value of 2.50 for cfDNA, with a sensitivity of 81.5% and specificity of 74.0% in predicting disease outcomes.

Conclusion

This study demonstrates a robust association between cfDNA and STEMI, indicating that cfDNA levels can be a valuable early prognostic factor for patients. Serial measurements of cfDNA during early disease onset hold promise as an effective approach for predicting survival outcomes in MI patients.

Circulating cell-free DNA-based methylation pattern in plasma for early diagnosis of esophagus cancer

With the increased awareness of early tumor detection, the importance of detecting and diagnosing esophageal cancer in its early stages has been underscored. Studies have consistently demonstrated the crucial role of methylation levels in circulating cell-free DNA (cfDNA) in identifying and diagnosing early-stage cancer. cfDNA methylation pertains to the methylation state within the genomic scope of cfDNA and is strongly associated with cancer development and progression. Several research teams have delved into the potential application of cfDNA methylation in identifying early-stage esophageal cancer and have achieved promising outcomes. Recent research supports the high sensitivity and specificity of cfDNA methylation in early esophageal cancer diagnosis, providing a more accurate and efficient approach for early detection and improved clinical management. Accordingly, this review aims to present an overview of methylation-based cfDNA research with a focus on the latest developments in the early detection of esophageal cancer. Additionally, this review summarizes advanced analytical technologies for cfDNA methylation that have significantly benefited from recent advancements in separation and detection techniques, such as methylated DNA immunoprecipitation sequencing (MeDIP-seq). Recent findings suggest that biomarkers based on cfDNA methylation may soon find successful applications in the early detection of esophageal cancer. However, large-scale prospective clinical trials are required to identify the potential of these biomarkers.

Short-term serial circulating tumor DNA assessment predicts therapeutic efficacy for patients with advanced pancreatic cancer

PURPOSE

We investigated the potential clinical utility of short-term serial KRAS-mutated circulating cell-free tumor DNA (ctDNA) assessment for predicting therapeutic response in patients undergoing first-line chemotherapy for advanced pancreatic cancer.

METHODS

We collected 144 blood samples from 18 patients with locally advanced or metastatic cancer that were undergoing initial first-line chemotherapy of gemcitabine plus nab-paclitaxel (GEM plus nab-PTX). Analysis of KRAS-mutated ctDNA was quantified by digital droplet polymerase chain reaction (ddPCR) as mutant allele frequency (MAF). This study investigated pretreatment KRAS-mutated ctDNA status and ctDNA kinetics every few days (days 1, 3, 5 and 7) after initiation of chemotherapy and their potential as predictive indicators.

RESULTS

Of the 18 enrolled patients, an increase in KRAS-mutated ctDNA MAF values from day 0-7 after initiation of chemotherapy was significantly associated with disease progression (P < 0.001). Meanwhile, positive pretreatment ctDNA status (MAF ≥ 0.02%) (P = 0.585) and carbohydrate antigen 19-9 (CA19-9) values above the median (P = 0.266) were not associated with disease progression. In univariate analysis, this short-term increase in ctDNA MAF values (day 0-7) was found to be associated with significantly shorter progression free survival (PFS) (hazard ration [HR], 24.234; range, (2.761-212.686); P = 0.0002).

CONCLUSION

This short-term ctDNA kinetics assessment may provide predictive information to reflect real-time therapeutic response and lead to effective refinement of regimen in patients with advanced pancreatic cancer undergoing systemic chemotherapy.

Cell-free fetal DNA (cffDNA) extraction from whole blood by using a fully automatic centrifugal microfluidic device based on displacement of magnetic silica beads

The purpose of this research was to design a fully automated centrifugal microfluidic system (Lab-on-a-Disk) for isolating cell free fetal DNAs (cffDNAs) from whole blood. To achieve this goal, magnetic silica beads were used, such that after attaching cffDNA to them, they were transferred between chambers by using external fixed magnets. All the standards and required steps for cffDNA extraction including plasma separation, adding proteinase K, lysis buffer, binding buffer, washing buffer, and elution buffer were considered in this designed disk. To evaluate the function of the disk, the collected samples were tested from several aspects. First, the purity of extracted plasma from whole blood was investigated which included hemoglobin test, hemocytometer, etc. This disk could extract 1.3 mL pure plasma from 3 mL blood with 45% hematocrit. The results of the extracted plasma showed 99% purity. Finally, the cffDNAs were examined by using a male fetal gender identification kit and real-time PCR machine. The results indicated the correct function of the disk in extracting cffDNAs in samples of 10 Landa from cycle 34 onwards. Compared to the clinical method, the disk not only was able to extract cffDNA in 20 min but also it led to less buffer consumption since the disk only required 1 mL plasma for extraction of cffDNAs.

cfDNA UniFlow: a unified preprocessing pipeline for cell-free DNA data from liquid biopsies

BACKGROUND

Cell-free DNA (cfDNA), a broadly applicable biomarker commonly sourced from urine or blood, is extensively used for research and diagnostic applications. In various settings, genetic and epigenetic information is derived from cfDNA. However, a unified framework for its processing is lacking, limiting the universal application of innovative analysis strategies and the joining of data sets.

FINDINGS

Here, we describe cfDNA UniFlow, a unified, standardized, and ready-to-use workflow for processing cfDNA samples. The workflow is written in Snakemake and can be scaled from stand-alone computers to cluster environments. It includes methods for processing raw genome sequencing data as well as specialized approaches for correcting sequencing errors, filtering, and quality control. Sophisticated methods for detecting copy number alterations and estimating and correcting GC-related biases are readily incorporated. Furthermore, it includes methods for extracting, normalizing, and visualizing coverage signals around user-defined regions in case-control settings. Ultimately, all results and metrics are aggregated in a unified report, enabling easy access to a wide variety of information for further research and downstream analysis.

CONCLUSIONS

We provide an automated pipeline for processing cell-free DNA sampled from liquid biopsies, including a wide variety of additional functionalities like bias correction and signal extraction. With our focus on scalability and extensibility, we provide a foundation for future cfDNA research and faster clinical applications. The source code and extensive documentation are available on our GitHub repository (https://github.com/kircherlab/cfDNA-UniFlow).

Non-invasive cell-free DNA-based approach for the diagnosis of clinical miscarriage: A retrospective study

OBJECTIVE

To evaluate cell-free DNA (cfDNA) testing as a non-invasive approach to detecting aneuploidies in clinical miscarriages.

DESIGN

A retrospective cohort study of women with pregnancy loss.

SETTING

Hospitals and genetic analysis laboratories.

POPULATION OR SAMPLE

Pregnancy losses in the period 2021-2022.

METHODS

Results derived from non-invasive cfDNA testing (Veriseq NIPT Solution V2) of maternal blood and invasive analysis of products of conception (POC) (Ion ReproSeq) compared in 120 women who suffered a miscarriage.

MAIN OUTCOME MEASURES

Concordance rate results, cfDNA testing performance, non-informative rate (NIR) and fetal fraction (FF).

RESULTS

We found no significant differences in the NIR between invasive (iPOC) and non-invasive (niPOC) analysis of POC (10.0% [12/120] versus 16.7% [20/120]). Of 120 samples, 90 provided an informative result in iPOC and niPOC groups (75%). cfDNA analysis correctly identified 74/87 (85.1%) samples (excluding triploidies). Sensitivity and specificity were 79.4% and 100%, respectively; all discordant cases were female. A binomial logistic model suggested fetal sex as the only variable influencing the concordance rate (P = 0.035). A Y-chromosome-based FF estimate allowed the optimal reclassification of cfDNA of non-informative male fetuses and a more accurate evaluation of cfDNA testing performance. The difference between the two FF estimates (native algorithm and Y-chromosome-based) suggests that female non-concordant cases may represent non-informative cases.

CONCLUSIONS

Cell-free DNA-based testing provides a non-invasive approach to determining the genetic cause of clinical miscarriage.

A future blood test for acute traumatic spinal cord injury

Acute spinal cord injury (SCI) requires prompt diagnosis and intervention to minimize the risk of permanent neurologic deficit. Presently, SCI diagnosis and interventional planning rely on magnetic resonance imaging (MRI), which is not always available or feasible for severely injured patients. Detection of disease-specific biomarkers in biofluids via liquid biopsy may provide a more accessible and objective means of evaluating patients with suspected SCI. Cell-free DNA, which has been used for diagnosing and monitoring oncologic disease, may detect damage to spinal cord neurons via tissue-specific methylation patterns. Other types of biomarkers, including proteins and RNA species, have also been found to reflect neuronal injury and may be included as part of a multi-analyte assay to improve liquid biopsy performance. The feasibility of implementing liquid biopsy into current practices of SCI management is supported by the relative ease of blood sample collection as well as recent advancements in droplet digital polymerase chain reaction technology. In this review, we detail the current landscape of biofluid biomarkers for acute SCI and propose a framework for the incorporation of a putative blood test into the clinical management of SCI.

Emerging Applications of Liquid Biopsies in Ovarian Cancer

Liquid biopsy is a new diagnostic tool in precision oncology that can be used as a complementary or alternative method to surgical biopsies. It is a cutting-edge sampling technique that examines distinct cancer components, such as exosomes and circulating tumor cells discharged into the peripheral circulation, to identify tumor biomarkers through various methods, including polymerase chain reaction (PCR). Liquid biopsy has several benefits, including its non-invasiveness and practicality, which permit serial sampling and long-term monitoring of dynamic tumor changes. Ovarian cancer (OC), the most lethal gynecologic malignancy in the world, is typically diagnosed at stages II and III, which makes recovery and treatment extremely difficult. Relapsed OC and chemotherapy resistance of ovarian tumor cells are other clinical challenges. Although liquid biopsy is not a routinely used diagnostic test, it should be utilized in the diagnosis and prognosis of OC for early detection and treatment. It is less intrusive than conventional tissue biopsies, allowing for the continuous collection of serial blood samples to track cancer development in real time. Before therapeutic application, more investigation is required to pinpoint the particular release processes, the source tissue, and the biological significance of the bulk of liquid biopsy contents.

Cell-free chromatin immunoprecipitation to detect molecular pathways in heart transplantation

Existing monitoring approaches in heart transplantation lack the sensitivity to provide deep molecular assessments to guide management, or require endomyocardial biopsy, an invasive and blind procedure that lacks the precision to reliably obtain biopsy samples from diseased sites. This study examined plasma cell-free DNA chromatin immunoprecipitation sequencing (cfChIP-seq) as a noninvasive proxy to define molecular gene sets and sources of tissue injury in heart transplant patients. In healthy controls and in heart transplant patients, cfChIP-seq reliably detected housekeeping genes. cfChIP-seq identified differential gene signals of relevant immune and nonimmune molecular pathways that were predominantly down-regulated in immunosuppressed heart transplant patients compared with healthy controls. cfChIP-seq also identified cell-free DNA tissue sources. Compared with healthy controls, heart transplant patients demonstrated greater cell-free DNA from tissue types associated with heart transplant complications, including the heart, hematopoietic cells, lungs, liver, and vascular endothelium. cfChIP-seq may therefore be a reliable approach to profile dynamic assessments of molecular pathways and sources of tissue injury in heart transplant patients.

Circulating tumor DNA as liquid biopsy in lung cancer: Biological characteristics and clinical integration

Lung cancer maintains high morbidity and mortality rate globally despite significant advancements in diagnosis and treatment in the era of precision medicine. Pathological analysis of tumor tissue, the current gold standard for lung cancer diagnosis, is intrusive and intrinsically confined to evaluating the limited amount of tissues that could be physically extracted. However, tissue biopsy has several limitations, including the invasiveness of the procedure and difficulty in obtaining samples for patients at advanced stages., there Additionally,has been no major breakthrough in tumor biomarkers with high specificity and sensitivity, particularly for early-stage lung cancer. Liquid biopsy has been considered a feasible auxiliary tool for tearly dianosis, evaluating treatment responses and monitoring prognosis of lung cancer. Circulating tumor DNA (ctDNA), an ideal biomarker of liquid biopsy, has emerged as one of the most reliable tools for monitoring tumor processes at molecular levels. Herein, this review focuses on tumor heterogeneity to elucidate the superiority of liquid biopsy and retrospectively discussdeciphersolution. We systematically elaborate ctDNA biological characteristics, introduce methods for ctDNA detection, and discuss the current role of plasma ctDNA in lung cancer management. Finally, we summarize the drawbacks of ctDNA analysis and highlight its potential clinical application in lung cancer.

Liquid Biopsy in Head and Neck Cancer: Its Present State and Future Role in Africa

The rising mortality and morbidity rate of head and neck cancer (HNC) in Africa has been attributed to factors such as the poor state of health infrastructures, genetics, and late presentation resulting in the delayed diagnosis of these tumors. If well harnessed, emerging molecular and omics diagnostic technologies such as liquid biopsy can potentially play a major role in optimizing the management of HNC in Africa. However, to successfully apply liquid biopsy technology in the management of HNC in Africa, factors such as genetic, socioeconomic, environmental, and cultural acceptability of the technology must be given due consideration. This review outlines the role of circulating molecules such as tumor cells, tumor DNA, tumor RNA, proteins, and exosomes, in liquid biopsy technology for the management of HNC with a focus on studies conducted in Africa. The present state and the potential opportunities for the future use of liquid biopsy technology in the effective management of HNC in resource-limited settings such as Africa is further discussed.

Current advances in detecting genetic and epigenetic biomarkers of colorectal cancer

Colorectal carcinoma (CRC) is the third most common cancer in terms of diagnosis and the second in terms of mortality. Recent studies have shown that various proteins, extracellular vesicles (i.e., exosomes), specific genetic variants, gene transcripts, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and altered epigenetic patterns, can be used to detect, and assess the prognosis of CRC. Over the last decade, a plethora of conventional methodologies (e.g., polymerase chain reaction [PCR], direct sequencing, enzyme-linked immunosorbent assay [ELISA], microarray, in situ hybridization) as well as advanced analytical methodologies (e.g., microfluidics, electrochemical biosensors, surface-enhanced Raman spectroscopy [SERS]) have been developed for analyzing genetic and epigenetic biomarkers using both optical and non-optical tools. Despite these methodologies, no gold standard detection method has yet been implemented that can analyze CRC with high specificity and sensitivity in an inexpensive, simple, and time-efficient manner. Moreover, until now, no study has critically reviewed the advantages and limitations of these methodologies. Here, an overview of the most used genetic and epigenetic biomarkers for CRC and their detection methods are discussed. Furthermore, a summary of the major biological, technical, and clinical challenges and advantages/limitations of existing techniques is also presented.

Cell-free DNA reveals distinct pathology of multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a rare but life-threatening hyperinflammatory condition induced by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes pediatric COVID-19 (pCOVID-19). The relationship of the systemic tissue injury to the pathophysiology of MIS-C is poorly defined. We leveraged the high sensitivity of epigenomics analyses of plasma cell-free DNA (cfDNA) and plasma cytokine measurements to identify the spectrum of tissue injury and glean mechanistic insights. Compared with pediatric healthy controls (pHCs) and patients with pCOVID-19, patients with MIS-C had higher levels of cfDNA primarily derived from innate immune cells, megakaryocyte-erythroid precursor cells, and nonhematopoietic tissues such as hepatocytes, cardiac myocytes, and kidney cells. Nonhematopoietic tissue cfDNA levels demonstrated significant interindividual variability, consistent with the heterogenous clinical presentation of MIS-C. In contrast, adaptive immune cell-derived cfDNA levels were comparable in MIS-C and pCOVID-19 patients. Indeed, the cfDNA of innate immune cells in patients with MIS-C correlated with the levels of innate immune inflammatory cytokines and nonhematopoietic tissue-derived cfDNA, suggesting a primarily innate immunity-mediated response to account for the multisystem pathology. These data provide insight into the pathogenesis of MIS-C and support the value of cfDNA as a sensitive biomarker to map tissue injury in MIS-C and likely other multiorgan inflammatory conditions.