Cost-effective genomic prediction of critical economic traits in sturgeons through low-coverage sequencing.

Low-coverage whole-genome sequencing (LCS) offers a cost-effective alternative for sturgeon breeding, especially given the lack of SNP chips and the high costs associated with whole-genome sequencing. In this study, the efficiency of LCS for genotype imputation and genomic prediction was assessed in 643 sequenced Russian sturgeons (∼13.68×). The results showed that using BaseVar+STITCH at a sequencing depth of 2× with a sample size larger than 300 resulted in the highest genotyping accuracy. In addition, when the sequencing depth reached 0.5× and SNP density was reduced to 50 K through linkage disequilibrium pruning, the prediction accuracy was comparable to that of whole sequencing depth. Furthermore, an incremental feature selection method has the potential to improve prediction accuracy. This study suggests that the combination of LCS and imputation can be a cost-effective strategy, contributing to the genetic improvement of economic traits and promoting genetic gains in aquaculture species.

Exploring the potential of Oxford Nanopore Technologies sequencing for Mycobacterium tuberculosis sequencing: An assessment of R10 flowcells and V14 chemistry.

Oxford Nanopore Technologies (ONT) sequencing is a promising technology. We assessed the performance of the new ONT R10 flowcells and V14 rapid sequencing chemistry for Mtb whole genome sequencing of Mycobacterium tuberculosis (Mtb) DNA extracted from clinical primary liquid cultures (CPLCs). Using the recommended protocols for MinION Mk1C, R10.4.1 MinION flowcells, and the ONT Rapid Sequencing Kit V14 on six CPLC samples, we obtained a pooled library yield of 10.9 ng/µl, generated 1.94 Gb of sequenced bases and 214k reads after 48h in a first sequencing run. Only half (49%) of all generated reads met the Phred Quality score threshold (>8). To assess if the low data output and sequence quality were due to impurities present in DNA extracted directly from CPLCs, we added a pre-library preparation bead-clean-up step and included purified DNA obtained from an Mtb subculture as a control sample in a second sequencing run. The library yield for DNA extracted from four CPLCs and one Mtb subculture (control) was similar (10.0 ng/µl), 2.38 Gb of bases and 822k reads were produced. The quality was slightly better with 66% of the produced reads having a Phred Quality >8. A third run of DNA from six CPLCs with bead clean-up pre-processing produced a low library yield (±1 Gb of bases, 166k reads) of low quality (51% of reads with a Phred Quality score >8). A median depth of coverage above 10× was only achieved for five of 17 (29%) sequenced libraries. Compared to Illumina WGS of the same samples, accurate lineage predictions and full drug resistance profiles from the generated ONT data could not be determined by TBProfiler. Further optimization of the V14 ONT rapid sequencing chemistry and library preparation protocol is needed for clinical Mtb WGS applications.

Transposase-assisted tagmentation: an economical and scalable strategy for single-worm whole-genome sequencing.

AlphaMissense identifies 23 million human missense variants as likely pathogenic, but only 0.1% have been clinically classified. To experimentally validate these predictions, chemical mutagenesis presents a rapid, cost-effective method to produce billions of mutations in model organisms. However, the prohibitive costs and limitations in the throughput of whole-genome sequencing (WGS) technologies, crucial for variant identification, constrain its widespread application. Here, we introduce a Tn5 transposase-assisted tagmentation technique for conducting WGS in Caenorhabditis elegans, Escherichia coli, Saccharomyces cerevisiae, and Chlamydomonas reinhardtii. This method, demands merely 20 min of hands-on time for a single-worm or single-cell clones and incurs a cost below 10 US dollars. It effectively pinpoints causal mutations in mutants defective in cilia or neurotransmitter secretion and in mutants synthetically sterile with a variant analogous to the B-Raf Proto-oncogene, Serine/Threonine Kinase (BRAF) V600E mutation. Integrated with chemical mutagenesis, our approach can generate and identify missense variants economically and efficiently, facilitating experimental investigations of missense variants in diverse species.

Implementation of a high-throughput whole genome sequencing approach with the goal of maximizing efficiency and cost effectiveness to improve public health.

This manuscript describes the development of a streamlined, cost-effective laboratory workflow to meet the demands of increased whole genome sequence (WGS) capacity while achieving mandated quality metrics. From 2020 to 2021, the Wadsworth Center Bacteriology Laboratory (WCBL) used a streamlined workflow to sequence 5,743 genomes that contributed sequence data to nine different projects. The combined use of the QIAcube HT, Illumina DNA Prep using quarter volume reactions, and the NextSeq allowed the WCBL to process all samples that required WGS while also achieving a median turn-around time of 7 days (range 4 to 10 days) and meeting minimum sequence quality requirements. Public Health Laboratories should consider implementing these methods to aid in meeting testing requirements within budgetary restrictions. IMPORTANCE: Public Health Laboratories that implement whole genome sequencing (WGS) technologies may struggle to find the balance between sample volume and cost effectiveness. We present a method that allows for sequencing of a variety of bacterial isolates in a cost-effective manner. This report provides specific strategies to implement high-volume WGS, including an innovative, low-cost solution utilizing a novel quarter volume sequencing library preparation. The methods described support the use of high-throughput DNA extraction and WGS within budgetary constraints, strengthening public health responses to outbreaks and disease surveillance.

Low-pass whole genome sequencing is a reliable and cost-effective approach for copy number variant analysis in the clinical setting.

INTRODUCTION: Next generation sequencing technology has greatly reduced the cost and time required for sequencing a genome. An approach that is rapidly being adopted as an alternative method for CNV analysis is the low-pass whole genome sequencing (LP-WGS). Here, we evaluated the performance of LP-WGS to detect copy number variants (CNVs) in clinical cytogenetics. MATERIALS AND METHODS: DNA samples with known CNVs detected by chromosomal microarray analyses (CMA) were selected for comparison and used as positive controls; our panel included 44 DNA samples (12 prenatal and 32 postnatal), comprising a total of 55 chromosome imbalances. The selected cases were chosen to provide a wide range of clinically relevant CNVs, the vast majority being associated with intellectual disability or recognizable syndromes. The chromosome imbalances ranged in size from 75 kb to 90.3 Mb, including aneuploidies and two cases of mosaicism. RESULTS: All CNVs were successfully detected by LP-WGS, showing a high level of consistency and robust performance of the sequencing method. Notably, the size of chromosome imbalances detected by CMA and LP-WGS were compatible between the two different platforms, which indicates that the resolution and sensitivity of the LP-WGS approach are at least similar to those provided by CMA. DISCUSSION: Our data show the potential use of LP-WGS to detect CNVs in clinical diagnosis and confirm the method as an alternative for chromosome imbalances detection. The diagnostic effectiveness and feasibility of LP-WGS, in this technical validation study, were evidenced by a clinically representative dataset of CNVs that allowed a systematic assessment of the detection power and the accuracy of the sequencing approach. Further, since the software used in this study is commercially available, the method can easily be tested and implemented in a routine diagnostic setting.

Economic evaluations of whole-genome sequencing for pathogen identification in public health surveillance and health-care-associated infections: a systematic review.

Whole-genome sequencing (WGS) has resulted in improvements to pathogen characterisation for the rapid investigation and management of disease outbreaks and surveillance. We conducted a systematic review to synthesise the economic evidence of WGS implementation for pathogen identification and surveillance. Of the 2285 unique publications identified through online database searches, 19 studies met the inclusion criteria. The economic evidence to support the broader application of WGS as a front-line pathogen characterisation and surveillance tool is insufficient and of low quality. WGS has been evaluated in various clinical settings, but these evaluations are predominantly investigations of a single pathogen. There are also considerable variations in the evaluation approach. Economic evaluations of costs, effectiveness, and cost-effectiveness are needed to support the implementation of WGS in public health settings.

Return of Results in Genomic Research Using Large-Scale or Whole Genome Sequencing: Toward a New Normal.

Genome sequencing is increasingly used in research and integrated into clinical care. In the research domain, large-scale analyses, including whole genome sequencing with variant interpretation and curation, virtually guarantee identification of variants that are pathogenic or likely pathogenic and actionable. Multiple guidelines recommend that findings associated with actionable conditions be offered to research participants in order to demonstrate respect for autonomy, reciprocity, and participant interests in health and privacy. Some recommendations go further and support offering a wider range of findings, including those that are not immediately actionable. In addition, entities covered by the US Health Insurance Portability and Accountability Act (HIPAA) may be required to provide a participant's raw genomic data on request. Despite these widely endorsed guidelines and requirements, the implementation of return of genomic results and data by researchers remains uneven. This article analyzes the ethical and legal foundations for researcher duties to offer adult participants their interpreted results and raw data as the new normal in genomic research.

[Assessment of available and currently applied typing methods including genome-based methods for zoonotic pathogens with a focus on Salmonella enterica]. / Bestandsaufnahme der verfügbaren und aktuell eingesetzten Typisierungsmethoden einschließlich genombasierter Verfahren von Zoonoseerregern am Beispiel von Salmonella enterica.

BACKGROUND: In recent years, whole genome sequencing (WGS) in combination with bioinformatic analyses has become state of the art in evaluating the pathogenicity/resistance potential and relatedness of bacteria. WGS analysis thus represents a central tool in the investigation of the resistance and virulence potential of pathogens, as well as their dissemination via outbreak clusters and transmission chains within the framework of molecular epidemiology. In order to gain an overview of the available genotypic and phenotypic methods used for pathogen typing of Salmonella and Shiga toxin-producing and enterohemorrhagic Escherichia coli (STEC/EHEC) in Germany at state and federal level, along with the availability of WGS-based typing and corresponding analytical methods, a survey of laboratories was conducted. METHODS: An electronic survey of laboratories working for public health protection and consumer health protection was conducted from February to June 2020. RESULTS AND CONCLUSION: The results of the survey showed that many of the participating laboratories provide a wide range of phenotypic and molecular methods. Molecular typing is most commonly used for species identification of Salmonella. In many cases, WGS-based methods have already been established at federal and state institutions or are in the process of being established. The Illumina sequencing technology is the most widely used technology. The survey confirms the importance of molecular biology and whole genome typing technologies for laboratories in the diagnosis of bacterial zoonotic pathogens.

Prueba genética para determinación de pacientes de bajo riesgo de cáncer de pulmón con broncoscopia no concluyente / Genetic test for determination of patients at low risk of lung cancer with bronchoscopy at the end

INTRODUCCIÓN: El cáncer de pulmón es el cuarto cáncer más frecuente diagnosticado en la Unión Europea y afecta a más de 315.000 personas. En España, aunque en los últimos años se observa una tendencia descendente, los nuevos casos se concentran en los grupos de edad de 75 y más años (32%) y de 65-74 años (32%), seguido del grupo de 55-64 años (25%). El grupo de edad de 15-54 años acumula un 11% de los casos. En el diagnóstico del cáncer de pulmón el enfoque preferido utiliza la imagen (radiografía de tórax, tomografía computarizada) como una guía y la biopsia invasiva como una herramienta para confirmar tanto el diagnóstico histopatológico como el estadio de la enfermedad. Algunas biopsias pueden llegar a ser innecesarias y además conllevan riesgos significativos y costosos. Existe, por lo tanto, una necesidad urgente de desarrollar enfoques que puedan discriminar de manera más efectiva, para lo cual los biomarcadores moleculares presentan un gran potencial. El clasificador de secuenciación genómica Percepta GSC® es un dispositivo diseñado para mejorar el diagnóstico de pacientes con cáncer de pulmón al reducir la necesidad de procedimientos invasivos después de detectar nódulos o lesiones pulmonares potencialmente cancerosas en exploraciones de tomografía computarizada. OBJETIVOS: Evaluar la seguridad y eficacia de la prueba genómica (PERCEPTA GSC®) para la determinación de pacientes de bajo riesgo de cáncer de pulmón con broncoscopia no concluyente en pacientes con nódulos pulmonares potencialmente cancerosos. METODOLOGÍA: Se ha llevado a cabo una búsqueda bibliográfica estructurada para la identificación de estudios de evidencia sobre pruebas genómicas para la determinación de pacientes de bajo riesgo de cáncer de pulmón con broncoscopia no concluyente, incluyendo, entre otros, los siguientes términos en lenguaje libre y controlado: lung neoplasms, bronchoscopy, genomic testing y risk, así como el término del dispositivo concreto a evaluar: percepta. Se realizó un análisis descriptivo preliminar para proporcionar información sobre las características de cada estudio. RESULTADOS: Siguiendo los criterios de inclusión y exclusión, el proceso final de selección llevó a la inclusión de siete estudios, y de la revisión manual incluidas en los artículos seleccionados y de la actualización de la búsqueda, se recuperaron una y tres referencias más respectivamente. La mayor parte de los estudios individuales incluidos se basan en las cohortes de pacientes recuperadas de los estudios AEGIS-I y AEGIS-II sobre la expresión génica epitelial de las vías respiratorias en el diagnóstico de cáncer de pulmón. Los resultados de los estudios incluidos mostraban una ventaja del clasificador Percepta en la reducción del uso de procedimientos invasivos en pacientes con sospecha de cáncer de pulmón. Del mismo modo, la información proporcionada por Percepta mostraba que podría influir significativamente en las decisiones clínicas al ayudar a los clínicos en la determinación de la estrategia de manejo más apropiada para los pacientes. Finalmente, estudios que incluían análisis coste-efectividad sugerían que la implementación de clasificadores genéticos podría considerarse una estrategia eficiente para el diagnóstico de cáncer de pulmón. CONCLUSIONES: El test Percepta GSC podría ser una herramienta confiable y efectiva para evaluar el riesgo de cáncer en nódulos pulmonares sospechosos en un entorno clínico. Sin embargo, es importante contar con resultados de estudios de alta calidad metodológica para respaldar de manera suficiente, contextualizada y objetiva la decisión final.

INTRODUCTION: Lung cancer is the fourth most common cancer in the European Union with more than 315,000 patients. In Spain, there is a decreasing trend, and new cases occur mainly in the over-74-year-old (32%) and 65- to 74-year-old (32%) age groups, followed by those aged 55-64 years old (25%). The 15-54 years old age group accounts for just 11% of cases. For the diagnosis of lung cancer, the preferred approach is to use imaging (chest X-ray, computed tomography [CT]) as a guide for initial assessment and invasive biopsy as a tool for histological confirmation of the diagnosis and staging of the disease. Some biopsies may be unnecessary as well as being associated with a higher risks and costs. There is, therefore, an urgent need to develop approaches with better discriminatory power, molecular biomarkers showing great potential. The Percepta® Genomic Sequencing Classifier (GSC) is a device designed to improve the diagnosis of patients with lung cancer, reducing the need for invasive procedures after identifying potentially cancerous nodules or lung lesions on CT imaging. OBJECTIVES: To assess the safety and efficacy of the PERCEPTA® GSC test for the classification of patients at low risk of lung cancer with potentially cancerous lung nodules but inconclusive bronchoscopy findings. METHODOLOGY: A structured literature search was performed to retrieve studies providing evidence on genomic tests for the classification of patients at low risk of lung cancer with inconclusive bronchoscopy findings, using lung neoplasms, bronchoscopy, genomic testing and risk, among other terms, as free text and controlled vocabulary, as well as the name of the specific device to be assessed: Percepta. A preliminary descriptive analysis was carried out to gather information on the characteristics of each study. RESULTS: Applying the inclusion and exclusion criteria, the final selection process yielded seven studies, while a manual review of the references in the selected papers and a search update retrieved one and three more studies, respectively. The majority of the individual studies included were based on cohorts of patients from the AEGIS-I and AEGIS-II studies on airway epithelial gene expression in the diagnosis of lung cancer. The data from the studies included showed an advantage of using the Percepta classifier in terms of a reduction in the use of invasive procedures in patients with suspected lung cancer. Further, the information provided by Percepta was shown to significantly influence clinical decisions by helping clinicians in the identification of the most appropriate management strategy for patients. Finally, the studies that included cost-effectiveness analysis suggested that the use of genomic classifiers could be considered an efficient strategy for the diagnosis of lung cancer. CONCLUSIONS: The Percepta® GSC test may be a reliable and effective tool for assessing cancer risk in patients with suspicious lung nodules in a clinical setting. Nonetheless, further data are required from high quality research to provide sufficient objective support and context for the final decision on whether to recommend the adoption of this technology.

Real-world economic evaluation of prospective rapid whole-genome sequencing compared to a matched retrospective cohort of critically ill pediatric patients in the United States.

There is an increasing demand for supporting the adoption of rapid whole-genome sequencing (rWGS) by demonstrating its real-world value. We aimed to assess the cost-effectiveness of rWGS in critically ill pediatric patients with diseases of unknown cause. Data were collected prospectively of patients admitted to the Nicklaus Children's Hospital's intensive care units from March 2018 to September 2020, with rWGS (N = 65). Comparative data were collected in a matched retrospective cohort with standard diagnostic genetic testing. We determined total costs, diagnostic yield (DY), and incremental cost-effectiveness ratio (ICER) adjusted for selection bias and right censoring. Sensitivity analyses explored the robustness of ICER through bootstrapping. rWGS resulted in a diagnosis in 39.8% while standard testing in 13.5% (p = 0.026). rWGS resulted in a mean saving per person of $100,440 (SE = 26,497, p < 0.001) and a total of $6.53 M for 65 patients. rWGS in critically ill pediatric patients is cost-effective, cost-saving, shortens diagnostic odyssey, and triples the DY of traditional approaches.

Incremental net benefit of whole genome sequencing for newborns and children with suspected genetic disorders: Systematic review and meta-analysis of cost-effectiveness evidence.

BACKGROUND: The introduction of massive parallel sequencing has contributed to a decline in sequencing costs. In recent years, whole-exome sequencing (WES) and whole-genome sequencing (WGS) have been increasingly adopted for diagnostic purposes in individuals with suspected genetic diseases. However, a debate is still ongoing in the scientific community about the superiority of WGS over WES in terms of cost-effectiveness. The aim of this study is to assess whether WGS, for the pediatric population with suspected genetic disorders, is cost-effective with respect to WES and chromosomal microarray (CMA) by pooling incremental net benefits. MATERIALS AND METHODS: Articles were retrieved from PubMed, Web of Science, Embase and Scopus from 2015 to 2021. The dominance ranking matrix (DRM) tool was adopted to provide a qualitative synthesis of all the included studies. Incremental net benefits (INBs) were estimated and meta-analysis was implemented to pool INBs across studies. RESULTS: The database search identified 1600 publications of which four articles were considered eligible for the meta-analysis. The pooled INB of WGS over WES was estimated at I$4073 (95% CI I$2426 - I$5720). The pooled INB of WGS over CMA amounted to I$6003 (95% CI I$2863 - I$9143). CONCLUSIONS: WGS could be cost-effective in the diagnostic workup of affected infants and children. Further economic evaluations however are needed for comparing WGS versus WES and confirm the present conclusions.

5WBF: a low-cost and straightforward whole blood filtration method suitable for whole-genome sequencing of Plasmodium falciparum clinical isolates.

BACKGROUND: Whole-genome sequencing (WGS) is becoming increasingly helpful to assist malaria control programmes. A major drawback of this approach is the large amount of human DNA compared to parasite DNA extracted from unprocessed whole blood. As red blood cells (RBCs) have a diameter of about 7-8 µm and exhibit some deformability, it was hypothesized that cheap and commercially available 5 µm filters might retain leukocytes but much less of Plasmodium falciparum-infected RBCs. This study aimed to test the hypothesis that such a filtration method, named 5WBF (for 5 µm Whole Blood Filtration), may provide highly enriched parasite material suitable for P. falciparum WGS. METHODS: Whole blood was collected from five patients experiencing a P. falciparum malaria episode (ring-stage parasitaemia range: 0.04-5.5%) and from mock samples obtained by mixing synchronized, ring-stage cultured P. falciparum 3D7 parasites with uninfected human whole blood (final parasitaemia range: 0.02-1.1%). These whole blood samples (50 to 400 µL) were diluted in RPMI 1640 medium or PBS 1× buffer and filtered with a syringe connected to a 5 µm commercial filter. DNA was extracted from 5WBF-treated and unfiltered counterpart blood samples using a commercial kit. The 5WBF method was evaluated on the ratios of parasite:human DNA assessed by qPCR and by sequencing depth and percentages of coverage from WGS data (Illumina NextSeq 500). As a comparison, the popular selective whole-genome amplification (sWGA) method, which does not rely on blood filtration, was applied to the unfiltered counterpart blood samples. RESULTS: After applying 5WBF, qPCR indicated an average of twofold loss in the amount of parasite template DNA (Pf ARN18S gene) and from 4096- to 65,536-fold loss of human template DNA (human ß actin gene). WGS analyses revealed that > 95% of the  parasite nuclear and organellar genomes were all covered at ≥ 10× depth for all samples tested. In sWGA counterparts, the organellar genomes were poorly covered and from 47.7 to 82.1% of the nuclear genome was covered at ≥ 10× depth depending on parasitaemia. Sequence reads were homogeneously distributed across gene sequences for 5WBF-treated samples (n = 5460 genes; mean coverage: 91×; median coverage: 93×; 5th percentile: 70×; 95th percentile: 103×), allowing the identification of gene copy number variations such as for gch1. This later analysis was not possible for sWGA-treated samples, as a much more heterogeneous distribution of reads across gene sequences was observed (mean coverage: 80×; median coverage: 51×; 5th percentile: 7×; 95th percentile: 245×). CONCLUSIONS: The novel 5WBF leucodepletion method is simple to implement and based on commercially available, standardized 5 µm filters which cost from 1.0 to 1.7€ per unit depending on suppliers. 5WBF permits extensive genome-wide analysis of P. falciparum ring-stage isolates from minute amounts of whole blood even with parasitaemias as low as 0.02%.

Assessment of two-pool multiplex long-amplicon nanopore sequencing of SARS-CoV-2.

Genomic surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays an important role in COVID-19 pandemic control and elimination efforts, especially by elucidating its global transmission network and illustrating its viral evolution. The deployment of multiplex PCR assays that target SARS-CoV-2 followed by either massively parallel or nanopore sequencing is a widely-used strategy to obtain genome sequences from primary samples. However, multiplex PCR-based sequencing carries an inherent bias of sequencing depth among different amplicons, which may cause uneven coverage. Here we developed a two-pool, long-amplicon 36-plex PCR primer panel with ~1000-bp amplicon lengths for full-genome sequencing of SARS-CoV-2. We validated the panel by assessing nasopharyngeal swab samples with a <30 quantitative reverse transcription PCR cycle threshold value and found that ≥90% of viral genomes could be covered with high sequencing depths (≥20% mean depth). In comparison, the widely-used ARTIC panel yielded 79%-88% high-depth genome regions. We estimated that ~5 Mbp nanopore sequencing data may ensure a >95% viral genome coverage with a ≥10-fold depth and may generate reliable genomes at consensus sequence levels. Nanopore sequencing yielded false-positive variations with frequencies of supporting reads <0.8, and the sequencing errors mostly occurred on the 5' or 3' ends of reads. Thus, nanopore sequencing could not elucidate intra-host viral diversity.

An accessible, efficient and global approach for the large-scale sequencing of bacterial genomes.

We have developed an efficient and inexpensive pipeline for streamlining large-scale collection and genome sequencing of bacterial isolates. Evaluation of this method involved a worldwide research collaboration focused on the model organism Salmonella enterica, the 10KSG consortium. Following the optimization of a logistics pipeline that involved shipping isolates as thermolysates in ambient conditions, the project assembled a diverse collection of 10,419 isolates from low- and middle-income countries. The genomes were sequenced using the LITE pipeline for library construction, with a total reagent cost of less than USD$10 per genome. Our method can be applied to other large bacterial collections to underpin global collaborations.

Revisiting the out of Africa event with a deep-learning approach.

Anatomically modern humans evolved around 300 thousand years ago in Africa. They started to appear in the fossil record outside of Africa as early as 100 thousand years ago, although other hominins existed throughout Eurasia much earlier. Recently, several studies argued in favor of a single out of Africa event for modern humans on the basis of whole-genome sequence analyses. However, the single out of Africa model is in contrast with some of the findings from fossil records, which support two out of Africa events, and uniparental data, which propose a back to Africa movement. Here, we used a deep-learning approach coupled with approximate Bayesian computation and sequential Monte Carlo to revisit these hypotheses from the whole-genome sequence perspective. Our results support the back to Africa model over other alternatives. We estimated that there are two sequential separations between Africa and out of African populations happening around 60-90 thousand years ago and separated by 13-15 thousand years. One of the populations resulting from the more recent split has replaced the older West African population to a large extent, while the other one has founded the out of Africa populations.

Serial assessment of measurable residual disease in medulloblastoma liquid biopsies.

Nearly one-third of children with medulloblastoma, a malignant embryonal tumor of the cerebellum, succumb to their disease. Conventional response monitoring by imaging and cerebrospinal fluid (CSF) cytology remains challenging, and a marker for measurable residual disease (MRD) is lacking. Here, we show the clinical utility of CSF-derived cell-free DNA (cfDNA) as a biomarker of MRD in serial samples collected from children with medulloblastoma (123 patients, 476 samples) enrolled on a prospective trial. Using low-coverage whole-genome sequencing, tumor-associated copy-number variations in CSF-derived cfDNA are investigated as an MRD surrogate. MRD is detected at baseline in 85% and 54% of patients with metastatic and localized disease, respectively. The number of MRD-positive patients declines with therapy, yet those with persistent MRD have significantly higher risk of progression. Importantly, MRD detection precedes radiographic progression in half who relapse. Our findings advocate for the prospective assessment of CSF-derived liquid biopsies in future trials for medulloblastoma.

Whole genome sequencing in oncology: using scenario drafting to explore future developments.

BACKGROUND: In oncology, Whole Genome Sequencing (WGS) is not yet widely implemented due to uncertainties such as the required infrastructure and expertise, costs and reimbursements, and unknown pan-cancer clinical utility. Therefore, this study aimed to investigate possible future developments facilitating or impeding the use of WGS as a molecular diagnostic in oncology through scenario drafting. METHODS: A four-step process was adopted for scenario drafting. First, the literature was searched for barriers and facilitators related to the implementation of WGS. Second, they were prioritized by international experts, and third, combined into coherent scenarios. Fourth, the scenarios were implemented in an online survey and their likelihood of taking place within 5 years was elicited from another group of experts. Based on the minimum, maximum, and most likely (mode) parameters, individual Program Evaluation and Review Technique (PERT) probability density functions were determined. Subsequently, individual opinions were aggregated by performing unweighted linear pooling, from which summary statistics were extracted and reported. RESULTS: Sixty-two unique barriers and facilitators were extracted from 70 articles. Price, clinical utility, and turnaround time of WGS were ranked as the most important aspects. Nine scenarios were developed and scored on likelihood by 18 experts. The scenario about introducing WGS as a clinical diagnostic with a lower price, shorter turnaround time, and improved degree of actionability, scored the highest likelihood (median: 68.3%). Scenarios with low likelihoods and strong consensus were about better treatment responses to more actionable targets (26.1%), and the effect of centralizing WGS (24.1%). CONCLUSIONS: Based on current expert opinions, the implementation of WGS as a clinical diagnostic in oncology is heavily dependent on the price, clinical utility (both in terms of identifying actionable targets as in adding sufficient value in subsequent treatment), and turnaround time. These aspects and the optimal way of service provision are the main drivers for the implementation of WGS and should be focused on in further research. More knowledge regarding these factors is needed to inform strategic decision making regarding the implementation of WGS, which warrants support from all relevant stakeholders.

Pathogenic potential assessment of the Shiga toxin-producing Escherichia coli by a source attribution-considered machine learning model.

Instead of conventional serotyping and virulence gene combination methods, methods have been developed to evaluate the pathogenic potential of newly emerging pathogens. Among them, the machine learning (ML)-based method using whole-genome sequencing (WGS) data are getting attention because of the recent advances in ML algorithms and sequencing technologies. Here, we developed various ML models to predict the pathogenicity of Shiga toxin-producing Escherichia coli (STEC) isolates using their WGS data. The input dataset for the ML models was generated using distinct gene repertoires from positive (pathogenic) and negative (nonpathogenic) control groups in which each STEC isolate was designated based on the source attribution, the relative risk potential of the isolation sources. Among the various ML models examined, a model using the support vector machine (SVM) algorithm, the SVM model, discriminated between the two control groups most accurately. The SVM model successfully predicted the pathogenicity of the isolates from the major sources of STEC outbreaks, the isolates with the history of outbreaks, and the isolates that cannot be assessed by conventional methods. Furthermore, the SVM model effectively differentiated the pathogenic potentials of the isolates at a finer resolution. Permutation importance analyses of the input dataset further revealed the genes important for the estimation, proposing the genes potentially essential for the pathogenicity of STEC. Altogether, these results suggest that the SVM model is a more reliable and broadly applicable method to evaluate the pathogenic potential of STEC isolates compared with conventional methods.

Identification of putative causal loci in whole-genome sequencing data via knockoff statistics.

The analysis of whole-genome sequencing studies is challenging due to the large number of rare variants in noncoding regions and the lack of natural units for testing. We propose a statistical method to detect and localize rare and common risk variants in whole-genome sequencing studies based on a recently developed knockoff framework. It can (1) prioritize causal variants over associations due to linkage disequilibrium thereby improving interpretability; (2) help distinguish the signal due to rare variants from shadow effects of significant common variants nearby; (3) integrate multiple knockoffs for improved power, stability, and reproducibility; and (4) flexibly incorporate state-of-the-art and future association tests to achieve the benefits proposed here. In applications to whole-genome sequencing data from the Alzheimer's Disease Sequencing Project (ADSP) and COPDGene samples from NHLBI Trans-Omics for Precision Medicine (TOPMed) Program we show that our method compared with conventional association tests can lead to substantially more discoveries.

Early technology assessment of using whole genome sequencing in personalized oncology.

Introduction: Personalized medicine-based treatments in advanced cancer hold the promise to offer substantial health benefits to genetic subgroups, but require efficient biomarker-based patient stratification to match the right treatment and may be expensive. Standard molecular diagnostics are currently very heterogeneous, and tests are often performed sequentially. The alternative to whole genome sequencing (WGS) i.e. simultaneously testing for all relevant DNA-based biomarkers thereby allowing immediate selection of the most optimal therapy, is more costly than current techniques. In the current implementation stage, it is important to explore the added value and cost-effectiveness of using WGS on a patient level and to assess optimal introduction of WGS on the level of the healthcare system.Areas covered: First, an overview of current worldwide initiatives concerning the use of WGS in clinical practice for cancer diagnostics is given. Second, a comprehensive, early health technology assessment (HTA) approach of evaluating WGS in the Netherlands is described, relating to the following aspects: diagnostic value, WGS-based treatment decisions, assessment of long-term health benefits and harms, early cost-effectiveness modeling, nation-wide organization, and Ethical, Legal and Societal Implications.Expert opinion: This study provides evidence to guide further development and implementation of WGS in clinical practice and the healthcare system.