Detection Of Cell-free DNA Research Articles

Smartphone-Based Pure DNAzyme Hydrogel Platform for Visible and Portable Colorimetric Detection of Cell-Free DNA.

Cell-free DNA (cfDNA), as a tumor marker, is of great importance for the diagnosis of cancer and targeted therapy. However, the need for huge analytical instruments for cfDNA analysis has restricted its practical applications, especially in rural areas and third-world countries. Herein, a portable and visual smartphone-based DNAzyme hydrogel platform is developed for cfDNA detection. The target cfDNA triggers rolling circle amplification to produce a G-quadruplex-comprised DNA hydrogel with an horseradish peroxidase (HRP)-like catalytic function, which further catalyzes the chromogenic substrate to generate a visible output signal. Notably, the naked-eye detection of cfDNA can be realized by the macroscale visibility and catalytic ability of the DNA hydrogel. The linear range of the DNAzyme hydrogel platform for cfDNA detection is 0.1 pM-1500 nM with a detection limit of 0.042 pM. Moreover, this platform is exploited for the detection of cfDNA in spiked human serum with favorable sensitivity and recovery. Therefore, the DNAzyme hydrogel platform provides highly promising potential for testing other nucleic acid biomarkers.

Utility of Cell-Free DNA Detection in Transplant Oncology.

Simple SummaryTransplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-liver transplant stages, and evaluate transplant rejection. The use of ctDNA to evaluate transplant rejection has been extensively studied in non-hepatocellular carcinoma (HCC) diseases. Emerging studies have also investigated the use of ctDNA detection in evaluating HCC tumor burden pre-and post-surgery as well as transplant rejection. However, extensive studies still need to be conducted to evaluate the role of ctDNA detection in the medical management of transplant oncology patients.Transplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. A critical concept that must be addressed to ensure the successful application of transplant oncology to patient care is efficient monitoring of tumor burden pre-and post-transplant and transplant rejection. Cell-free DNA (cfDNA) detection has emerged as a vital tool in revolutionizing the management of cancer patients who undergo organ transplantation. The advances in cfDNA technology have provided options to perform a pre-transplant evaluation of minimal residual disease (MRD) and post-transplant evaluation of cancer recurrence and transplant rejection. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-transplant stages, and evaluate transplant rejection.

Cell-Free DNA Detection of Tumor Mutations in Heterogeneous, Localized Prostate Cancer Via Targeted, Multiregion Sequencing.

Low-pass whole-genome and targeted sequencing with a machine-learning guided 2.5-Mb targeted panel were used to identify single nucleotide variants, small insertions and deletions (indels), and copy-number alterations in cfDNA. The majority of this study focuses on the subset of 21 patients with localized disease, although 45 total individuals were evaluated, including 15 healthy controls and nine men with metastatic castration-resistant prostate cancer. Plasma cfDNA was barcoded with duplex unique molecular identifiers. For localized cases, matched tumor tissue was collected from multiple regions (one to nine samples per patient) for comparison. Somatic tumor variants present in heterogeneous tumor foci from patients with localized disease were detected in cfDNA, and cfDNA mutational burden was found to track with disease severity. Somatic tissue alterations were identified in cfDNA, including nonsynonymous variants in FOXA1, PTEN, MED12, and ATM. Detection of these overlapping variants was associated with seminal vesicle invasion (P = .019) and with the number of variants initially found in the matched tumor tissue samples (P = .0005). Our findings demonstrate the potential of targeted cfDNA sequencing to detect somatic tissue alterations in heterogeneous, localized prostate cancer, especially in a setting where matched tumor tissue may be unavailable (ie, active surveillance or treatment monitoring).

A novel method for liquid-phase extraction of cell-free DNA for detection of circulating tumor DNA

Low yields of extracted cell-free DNA (cfDNA) from plasma limit continued development of liquid biopsy in cancer, especially in early-stage cancer diagnostics and cancer screening applications. We investigate a novel liquid-phase-based DNA isolation method that utilizes aqueous two-phase systems to purify and concentrate circulating cfDNA. The PHASIFY MAX and PHASIFY ENRICH kits were compared to a commonly employed solid-phase extraction method on their ability to extract cfDNA from a set of 91 frozen plasma samples from cancer patients. Droplet digital PCR (ddPCR) was used as the downstream diagnostic to detect mutant copies. Compared to the QIAamp Circulating Nucleic Acid (QCNA) kit, the PHASIFY MAX method demonstrated 60% increase in DNA yield and 171% increase in mutant copy recovery, and the PHASIFY ENRICH kit demonstrated a 35% decrease in DNA yield with a 153% increase in mutant copy recovery. A follow-up study with PHASIFY ENRICH resulted in the positive conversion of 9 out of 47 plasma samples previously determined negative with QCNA extraction (all with known positive tissue genotyping). Our results indicate that this novel extraction technique offers higher cfDNA recovery resulting in better sensitivity for detection of cfDNA mutations compared to a commonly used solid-phase extraction method.

Progress of Liquid Biopsy in the Diagnosis and Treatment of Lung Cancer with Malignant Pleural Effusion

肺癌是全球范围内死亡率最高的恶性肿瘤。晚期肺癌所致的恶性胸腔积液（malignant pleural effusion, MPE）严重影响患者的生活质量和预后。针对肿瘤的基因检测是制定精准治疗决策的基础，而组织活检取材存在风险，难以反复多次取样。液体活检由于具有无创性和可以反映肿瘤基因全貌的特点，在肺癌诊疗中的应用日益增多。基于血液样本的液体活检由于循环肿瘤DNA的含量极低，灵敏度和特异度有限。MPE中富含肿瘤细胞，检测其中的细胞游离DNA、细胞外囊泡和微小RNA等将有助于肺癌的诊断、治疗及预后的评估。本综述将探讨胸腔积液作为活检样本的研究，阐述液体活检在肺癌伴MPE诊疗中的研究进展。

Utility of plasma cell-free DNA detection using homobifunctional imidoesters using a microfluidic system for diagnosing active tuberculosis

Background It is difficult to diagnose tuberculosis (TB), particularly sputum-scarce pulmonary TB and extrapulmonary TB, using conventional diagnostic tests. Since these cases require additional invasive procedures to obtain appropriate specimens, new non-invasive diagnostic tests are needed. Plasma cell-free DNA (cfDNA) detection has gained interest as a novel diagnostic test for TB as it is convenient and less invasive. Therefore, we investigated the performance of enriched cfDNA for diagnosing pulmonary TB and extrapulmonary TB. Methods All patients suspected to have TB, who consented to the use of blood for detecting cfDNA, were prospectively enrolled from January 2019 to June 2020. We categorised the patients as confirmed, probable, possible TB, and not-TB. We compared the performance of cfDNA with those of conventional diagnostic tests. Results Among the 96 patients enrolled, 40 (41.7%) had TB, including 34 with confirmed TB and six probable TB, and 41 (42.7%) did not have TB. Acid-fast bacilli microscopy, Xpert MTB/RIF, and mycobacterial culture results were positive in 12 (31.6%), 22 (61.1%), and 25 (65.8%) patients, respectively. The sensitivity and specificity of cfDNA were 80.0% and 78.1%, respectively. While the sensitivity and specificity of cfDNA were similar to those of interferon-gamma releasing assay (IGRA) (sensitivity 80.6% and specificity 71.4%), the combined sensitivity and specificity of the two assays were 94.4% and 64.3%, respectively, which can be used to rule out TB. Conclusions Plasma cfDNA assay seems to be a useful adjunct to the current tests for diagnosing TB, especially when used in combination with IGRA for ruling out TB. Abbreviations TB tuberculosis cfDNA cell-free DNA PCR polymerase chain reaction AFB acid-fast bacilli IGRA interferon-gamma releasing assay CT computed tomography HIV human immunodeficiency virus

Microheater-integrated zinc oxide nanowire microfluidic device for hybridization-based detection of target single-stranded DNA

Detection of cell-free DNA (cfDNA) has an impact on DNA analysis in liquid biopsies. However, current strategies to detect cfDNA have limitations that should be overcome, such as having low sensitivity and requiring much time and a specialized instrument. Thus, non-invasive and rapid detection tools are needed for disease prevention and early-stage treatment. Here we developed a device having a microheater integrated with zinc oxide nanowires (microheater-ZnO-NWs) to detect target single-stranded DNAs (ssDNAs) based on DNA probe hybridization. We confirmed experimentally that our device realized in-situ annealed DNA probes by which we subsequently detected target ssDNAs. We envision that this device can be utilized for fundamental studies related to nanobiodevice-based DNA detection.

Advancements in Molecular Medicine and Tailor-Made Therapeutics

The marvelous success in the field of molecular therapeutics is being witnessed by science over the past few decades. From single cell RNA sequencing to circulating cell free DNA detection in the blood, astonishing accomplishments have been achieved. These advancements, however, are still confronting the challenges of the old times, such as non-specificity, inter-individual variability, and off-target effects. Molecular medicine as a science has provided a platform to address these problems, by tailoring according to the molecular and genetic profile of the individuals to increase the specificity of the treatment, to reduce variability, and to minimize adverse side effects. Advancements in this field are opening new vistas for shifting the paradigm across therapeutics and drug discovery, made possible through better understanding of the disease process at molecular level1.

Droplet digital PCR-based detection of circulating tumor DNA from pediatric high grade and diffuse midline glioma patients.

BackgroundThe use of liquid biopsy is of potential high importance for children with high grade (HGG) and diffuse midline gliomas (DMG), particularly where surgical procedures are limited, and invasive biopsy sampling not without risk. To date, however, the evidence that detection of cell-free DNA (cfDNA) or circulating tumor DNA (ctDNA) could provide useful information for these patients has been limited, or contradictory.MethodsWe optimized droplet digital PCR (ddPCR) assays for the detection of common somatic mutations observed in pediatric HGG/DMG, and applied them to liquid biopsies from plasma, serum, cerebrospinal fluid (CSF), and cystic fluid collected from 32 patients.ResultsAlthough detectable in all biomaterial types, ctDNA presented at significantly higher levels in CSF compared to plasma and/or serum. When applied to a cohort of 127 plasma specimens from 41 patients collected from 2011 to 2018 as part of a randomized clinical trial in pediatric non-brainstem HGG/DMG, ctDNA profiling by ddPCR was of limited use due to the small volumes (mean = 0.49 mL) available. In anecdotal cases where sufficient material was available, cfDNA concentration correlated with disease progression in two examples each of poor response in H3F3A_K27M-mutant DMG, and longer survival times in hemispheric BRAF_V600E-mutant cases.ConclusionTumor-specific DNA alterations are more readily detected in CSF than plasma. Although we demonstrate the potential of the approach to assessing tumor burden, our results highlight the necessity for adequate sample collection and approach to improve detection if plasma samples are to be used.

Enhanced detection of cell-free DNA (cfDNA) enables its use as a reliable biomarker for diagnosis and prognosis of gastric cancer.

Although circulating cell-free DNA (cfDNA) is a promising biomarker for the diagnosis and prognosis of various tumors, clinical correlation of cfDNA with gastric cancer has not been fully understood. To address this, we developed a highly sensitive cfDNA capture system by integrating polydopamine (PDA) and silica. PDA-silica hybrids incorporated different molecular interactions to a single system, enhancing cfDNA capture by 1.34-fold compared to the conventional silica-based approach (p = 0.001), which was confirmed using cell culture supernatants. A clinical study using human plasma samples revealed that the diagnostic accuracy of the new system to be superior than the commercially available cfDNA kit, as well as other serum antigen tests. Among the cancer patients, plasma cfDNA levels exhibited a good correlation with the size of a tumor. cfDNA was also predicative of distant metastasis, as the median cfDNA levels of metastatic cancer patients were ~60-fold higher than those without metastasis (p = 0.008). Furthermore, high concordance between tissue biopsy and cfDNA genomic analysis was found, as HER2 expression in cfDNA demonstrated an area under ROC curve (AUC) of 0.976 (p <0.001) for detecting patients with HER2-positive tumors. The new system also revealed high prognostic capability of cfDNA, as the concentration of cfDNA was highly associated with the survival outcomes. Our novel technology demonstrates the potential to achieve efficient detection of cfDNA that may serve as a reliable biomarker for gastric tumor.

Simultaneous Isolation of Circulating Nucleic Acids and EV-Associated Protein Biomarkers From Unprocessed Plasma Using an AC Electrokinetics-Based Platform.

The power of personalized medicine is based on a deep understanding of cellular and molecular processes underlying disease pathogenesis. Accurately characterizing and analyzing connections between these processes is dependent on our ability to access multiple classes of biomarkers (DNA, RNA, and proteins)—ideally, in a minimally processed state. Here, we characterize a biomarker isolation platform that enables simultaneous isolation and on-chip detection of cell-free DNA (cfDNA), extracellular vesicle RNA (EV-RNA), and EV-associated proteins in unprocessed biological fluids using AC Electrokinetics (ACE). Human biofluid samples were flowed over the ACE microelectrode array (ACE chip) on the Verita platform while an electrical signal was applied, inducing a field that reversibly captured biomarkers onto the microelectrode array. Isolated cfDNA, EV-RNA, and EV-associated proteins were visualized directly on the chip using DNA and RNA specific dyes or antigen-specific, directly conjugated antibodies (CD63, TSG101, PD-L1, GPC-1), respectively. Isolated material was also eluted off the chip and analyzed downstream by multiple methods, including PCR, RT-PCR, next-generation sequencing (NGS), capillary electrophoresis, and nanoparticle size characterization. The detection workflow confirmed the capture of cfDNA, EV-RNA, and EV-associated proteins from human biofluids on the ACE chip. Tumor specific variants and the mRNAs of housekeeping gene PGK1 were detected in cfDNA and RNA isolated directly from chips in PCR, NGS, and RT-PCR assays, demonstrating that high-quality material can be isolated from donor samples using the isolation workflow. Detection of the luminal membrane protein TSG101 with antibodies depended on membrane permeabilization, consistent with the presence of vesicles on the chip. Protein, morphological, and size characterization revealed that these vesicles had the characteristics of EVs. The results demonstrated that unprocessed cfDNA, EV-RNA, and EV-associated proteins can be isolated and simultaneously fluorescently analyzed on the ACE chip. The compatibility with established downstream technologies may also allow the use of the platform as a sample preparation method for workflows that could benefit from access to unprocessed exosomal, genomic, and proteomic biomarkers.

Liquid biopsy approaches for pleural effusion in lung cancer patients.

Genomic profiling of tumors has become the mainstay for diagnosis, treatment monitoring and a guide to precision medicine. However, in clinical practice, the detection of driver mutations in tumors has several procedural limitations owing to progressive disease and tumor heterogeneity. The current era of liquid biopsy promises a better solution. This diagnostic utility of liquid biopsy has been demonstrated by numerous studies for the detection of cell-free DNA (cfDNA) in plasma for disease diagnosis, prognosis, and prediction. However, cfDNAs are limited in blood circulation and still hurdles to achieve promising precision medicine. Malignant pleural effusion (MPE) is usually detected in advanced lung malignancy, which is rich in tumor cells. Extracellular vesicles and cfDNAs are the two major targets currently explored using MPE. Therefore, MPE can be used as a source of biomarkers in liquid biopsy for investigating tumor mutations. This review focuses on the liquid biopsy approaches for pleural effusion which may be explored as an alternative source for liquid biopsy in lung cancer patients to diagnose early disease progression.

Detection of Cell-Free DNA in Blood Plasma Samples of Cancer Patients.

Identifying mutations in tumors of cancer patients is a very important step in disease management. These mutations serve as biomarkers for tumor diagnosis as well as for the treatment selection and its response in cancer patients. The current gold standard method for detecting tumor mutations involves a genetic test of tumor DNA by means of tumor biopsies. However, this invasive method is difficult to be performed repeatedly as a follow-up test of the tumor mutational repertoire. Liquid biopsy is a new and emerging technique for detecting tumor mutations as an easy-to-use and non-invasive biopsy approach. Cancer cells multiply rapidly. In parallel, numerous cancer cells undergo apoptosis. Debris from these cells are released into a patient's circulatory system, together with finely fragmented DNA pieces, called cell-free DNA (cfDNA) fragments, which carry tumor DNA mutations. Therefore, for identifying cfDNA based biomarkers using liquid biopsy technique, blood samples are collected from the cancer patients, followed by the separation of plasma and buffy coat. Next, plasma is processed for the isolation of cfDNA, and the respective buffy coat is processed for the isolation of a patient's genomic DNA. Both nucleic acid samples are then checked for their quantity and quality; and analyzed for mutations using next-generation sequencing (NGS) techniques. In this manuscript, we present a detailed protocol for liquid biopsy, including blood collection, plasma, and buffy coat separation, cfDNA and germline DNA extraction, quantification of cfDNA or germline DNA, and cfDNA fragment enrichment analysis.

Detection of Cell-Free DNA in Blood Plasma Samples of Cancer Patients

Detection of Cell-Free DNA in Blood Plasma Samples of Cancer Patients

Is cell-free DNA in spent embryo culture medium an alternative to embryo biopsy for preimplantation genetic testing? A systematic review.

Preimplantation genetic testing (PGT) is increasingly used worldwide. It currently entails the use of invasive techniques, i.e. polar body, blastomere, trophectoderm biopsy or blastocentesis, to obtain embryonic DNA, with major technical limitations and ethical issues. Evidence suggests that invasive PGT can lead to genetic misdiagnosis in the case of embryo mosaicism, and, consequently, to the selection of affected embryos for implantation or to the destruction of healthy embryos. Recently, spent culture medium (SCM) has been proposed as an alternative source of embryonic DNA. An increasing number of studies have reported the detection of cell-free DNA in SCM and highlighted the diagnostic potential of non-invasive SCM-based PGT for assessing the genetic status of preimplantation human embryos obtained by IVF. The reliability of this approach for clinical applications, however, needs to be determined. In this systematic review, published evidence on non-invasive SCM-based PGT is presented, and its current benefits and limitations compared with invasive PGT. Then, ways of optimizing and standardizing procedures for non-invasive SCM-based PGT to prevent technical biases and to improve performance in future studies are discussed. Finally, clinical perspectives of non-invasive PGT are presented and its future applications in reproductive medicine highlighted.

The role of fetal DNA testing in obstetrics – an update

After the first detection of cell-free DNA (cfDNA) in the maternal plasma in the 70s, no one could imagine the tremendous impact of this discovery on the clinical practice. The present article aims at analyzing the actual knowledge about cfDNA from the clinician point of view. In the first part, the origin, kinetics and metabolization of cfDNA are explained. Afterwards, the major applications and limitations of cfDNA are presented. A vast part of the review is dedicated to the different techniques used for trisomy and sex chromosome detection and to their performance. The current international and local guidelines are presented at the end of the article.

The role of mucin cell-free DNA detection as a new marker for the study of acellular pseudomyxoma peritonei of appendicular origin by liquid biopsy.

Background:Acellular pseudomyxoma peritonei (aPMP) is a rare peritoneal malignancy characterized by the accumulation of large amounts of mucin (lacking tumor cells) in the peritoneum. Many cases account for several kilograms of mucin to be screened by the pathologist. This is a comprehensive study of three patients with aPMP, whose tumors showed KRAS mutation, allowing for the tracking of this marker by liquid biopsy.Methods:Pre and post-surgery plasma, and mucin removed during cytoreductive surgery were collected from the patients. KRAS mutations were analyzed using droplet digital polymerase chain reaction (ddPCR). Mucin was injected in mice. KRAS and cytokine levels were measured in plasma of the mice using ddPCR and a magnetic bead-based assay. Mucin microbiome was analyzed by 16S rRNA sequencing.Results:KRAS mutations were detected in mucin cell-free DNA (cfDNA) from the three patients but not in the pre or post-surgery plasma. Electron microscopy detected microparticles (diameter <0.4 µm) in mucin. Mucin from one patient grew up inside the peritoneal cavity of mice and human KRAS was identified in mucin cfDNA, but not in plasma. All mucins showed the same bacterial profile. Cytokine levels were slightly altered in mice.Conclusions:The three aPMP patients included in this study shared some common aspects: the absence of tumor cells in mucin, the presence of KRAS mutated cfDNA in mucin, and the absence of this tumor-derived mutation in the bloodstream, providing additional information to the routine pathological examinations and suggesting that mucin cfDNA could potentially play a role in aPMP recurrence and prognosis.

OS1.3 Tumor cell-free DNA detection in CSF for primary CNS lymphoma diagnosis

Abstract BACKGROUND Primary CNS lymphoma (PCNSL) is a rare disease accounting for around 3% of the primary brain tumors. In the vast majority of cases, PCNSL are classified as diffuse large B-cell lymphoma according to the WHO classification. The diagnosis is based on cranial MRI, in combination with a brain biopsy. In case of classical MRI findings, the identification of lymphoma cells in the cerebrospinal (CSF) or vitreous fluid by cytology and flow cytometry might obviate brain biopsy. The presence of the somatic mutation p.Leu265Pro (L265P) in MYD88 is detectable in 50 to 80% of PCNSL, and might also be helpful to confirm the diagnosis. The aim of our study was to evaluate the contribution of a highly sensitive digital droplet PCR, targeting the mutation L265P MYD88, for the detection of tumoral circulating DNA from CSF supernatant. MATERIAL AND METHODS We identified 9 PCNSL expressing the L265P mutation at diagnosis or relapse. The mutation was found by an allele specific PCR technique either on biopsy or in CSF cells. Circulating DNA was isolated from CSF supernatant with the « QiaAmp® circulating nucleic acid» kit. The quantity of DNA collected was estimated by quantitative PCR for a reference gene (albumine) with 7900HT (Life technologies™) device. Subsequently, the L265P MYD88 mutation was quantified by digital droplet PCR Biorad™: The droplets generated were amplified by PCR, detected with the QX200 Reader, and analyzed with the QuantaSoft™ software. RESULTS The circulating DNA concentration was low, varying between 0 and 2.2 ng/mL of CSF. However, the mutation was detected in the circulating DNA from CSF supernatant in 6 out of 9 cases (66%). The fractional abundance varied from 2.6 to 85%. In 3 cases, the mutation was detected even though cytology and flow cytometry did not reveal leptomeningeal disease. For 3 other cases, the mutation was not detected: The genome copy number was below 1 copy/µL, indicating a low analytical sensitivity for theses samples. CONCLUSION This study shows that circulating DNA is present in low concentration in CSF and can be amplified by a sensitive digital PCR for the L265P MYD88 mutation. The detection of circulating PCNSL DNA in CSF is possible and might be used to improve the non-invasive diagnosis of PCNSL. It might also help to select patients for targeted therapies.

Abstract 2420: The development of novel detection system for circulating tumor DNA using DNA chip system

Abstract Gene panels covering hundreds of mutation hotspots for detection of cell-free DNA (cfDNA) have been developed for the establishment of clinically practical circulating tumor (ctDNA) detection system. Although amplicon-based or capture-based genomic profiling of genes commonly mutated in cancer using next-generation sequencing (NGS) system have been developed, they are not sufficiently sensitive nor accurate to be used for clinical diagnosis in hospital. As a result of preliminary study using 87 advanced pancreatic cancer (stage lll/lV), we observed that one or more KRAS mutation(s) could be detected in 60.9% of patients with advanced pancreatic cancer by using the amplicon-based deep sequencing system. To develop more sensitive and accurate ctDNA detection system, we optimized conditions of our DNA chip system. We firstly used 100 synthetic DNA samples, whose KRAS mutant allele frequencies were from 0.1% to 10.0%, and investigated the quantitativity of our DNA chip system. We amplified target regions by PCR to obtain 2,000 copies of synthesized DNA. The PCR product was hybridized with the probe on the DNA chip. The fluorescence ratio (mutant allele fluorescence intensity / total fluorescence intensity) of 100 synthetic DNA samples were clearly distinguished to that of negative control by using the DNA chip system. We defined an appropriate cut-off values of small quantities (0.1%) of mutations. Furthermore, to confirm the accuracy and reliability of this method, we verified our DNA chip system using 15 plasma cfDNA samples from patients with mutant KRAS (0.1~10.0%) and 15 samples from patients without mutant KRAS as negative control. 10 ng of ctDNA which extracted from blood sample is used in PCR. We observed that detected mutant status by DNA chip was completely concordant (100%) with those by amplicon-based deep sequencing system. Our data confirmed that mutant allele in cfDNA can be sensitively and accurately detected by DNA chip system. These results suggest that the ctDNA detection system developed in this study could be a novel diagnostic tool for tumor burden, and could realize the ultra-early detection of refractory tumors including pancreatic cancer. Citation Format: Noriaki Nakamura, Hiroshi Okamura, Hirofumi Yamano, Hiromichi Ito, Hitoshi Zembutsu. The development of novel detection system for circulating tumor DNA using DNA chip system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2420.

Study for the Prediction of Active Rejection in Organs Using Donor-derived Cell-free DNA Detection

Study for the Prediction of Active Rejection in Organs Using Donor-derived Cell-free DNA Detection