Next-generation Sequencing Strategies Research Articles

Approaches for Lynch syndrome screening and characteristics of subtypes with mismatch repair deficiency in patients with colorectal carcinoma.

To evaluate different Lynch syndrome (LS) screening approaches and establish an efficient and sensitive strategy are critical for clinical practice. In total, 583 patients with colorectal carcinoma (CRC) at Fudan University Shanghai Cancer Center were enrolled. Patient samples were examined by immunohistochemistry (IHC) and next-generation sequencing (NGS), and MLH1 promoter hypermethylation (MPH) was detected in MLH1-deficient cases. Germline genetic testing was performed in cases with deleterious variants and large genomic rearrangements (LGRs) of tumor MMR genes were detected in cases with dMMR or MSI-H cases with no MMR germline variants. Our results showed that triage with IHC and followed by BRAF/MLH1 methylation testing (Strategy 1) identified 93.3% (70/75) of LS cases. IHC followed by germline NGS (Strategy 2) or direct tumor NGS (Strategy 3) both identified 98.7% (74/75) of LS cases. The proportion of LGRs in LS cases was 16.0% (12/75), while 84.0% (63/75) showed SNV/Indel. The average cost per patient was ¥6010.81, ¥6058.48, and ¥8029.98 for Strategy 1, Strategy 2 and Strategy 3, respectively. The average time spent on different strategies was 4.74 days (Strategy 1), 4.89 days (Strategy 2), and 14.50 days (Strategy 3) per patient, respectively. LS and Lynch-like syndrome (LLS) were associated with an earlier onset age than MPH. In conclusion, we compared different workflows for LS screening and IHC plus germline NGS is recommended for LS screening when taking sensitivity, time, and cost into account. Moreover, multiplex ligation-dependent probe amplification made up for the shortcoming of NGS and should be incorporated into routine screening.

P-568 Correlation of ploidy analysis in two types of zygotes with 3 pronuclei (3PN) observed: same size 3PNs and one micronucleus 3PNs

Abstract Study question Do all zygotes with three observed pronuclei have an actual triploid chromosomal complement? Summary answer Not all zygotes with 3 pronuclei observed are triploid, most of embryos with two even pronuclei and one smaller micronucleus are diploid. What is known already In the in vitro fertilization (IVF) setting, normal oocyte fertilisation is commonly confirmed 16–19 hours after conventional insemination or intracytoplasmic sperm injection (ICSI) with the appearance of two pronuclei (2PN). The presence three pronuclei (3PN) shows an abnormal oocyte fertilization. The incidence of 3PN zygotes in IVF is between 5.0%- 8.1% in conventional insemination and between 2.0%- 6.2% in ICSI. 3PN fertilized embryos are commonly discarded due to the suspected increased risk of a triploid chromosomal complement. However, no definitive genetic evidence has been obtained to show that all 3PN zygotes are chromosomally abnormal. Study design, size, duration An Ethics Committee for Investigation accredited this prospective observational study performed in a private centre between June 2023 and January 2024. 120 3PN zygotes from 113 cycles were cultivated until blastocyst stage. 46 were biopsied to clarify ploidy and euploidy status. 3PNs were divided into 2 groups based on the size of their pronuclei: Micro Triploid (MT) (smallest pronucleus <70% of the diameter of the largest pronucleus) and Pure Triploid (PT) (smallest >70% of the largest). Participants/materials, setting, methods Patients with 1 or more 3PN embryo were offered to participate, culturing and assessing their 3PNs. If 3PNs reached blastocyst stage, they were biopsied and analysed using Next-Generation Sequencing strategy with Single Nucleotide Polymorphisms technology without the need for parental samples, to assess ploidy and aneuploidy status. Measures of the pronuclei size were taken to sort the 3PNs in both groups. Comparisons between these groups regarding blastocyst rates, ploidy status and aneuploidy rates were assessed. Main results and the role of chance 120 3PNs zygotes were identified in 1054 cycles, representing 1.9% of all fertilized embryos. The blastocyst rate (BR) for overall 3PNs was 38.3%, while the BR for 2PNs on those 113 cycles was 58.3%, showing significant differences (p < 0.001). 3PN zygotes were classified into the MT and PT groups described above. The MT group had 40.4% BR, and the PT group had 37.0% BR. No significant differences were found. Of the 46 biopsied embryos, 37 were informative (80.4%), 17 for the MT group and 20 for the PT group. The diploidy rate for the overall 3PNs was 37.8% (n = 14). The MT group had 82.4% (n = 14) of diploidy rate, while the PT group had 0% diploid rate (n = 0), showing significant differences between them. (p < 0.001). The overall euploidy rate for 3PN zygotes was 28.6% (n = 12) (36.2 mean age), which was similar to the euploidy rate (30.3%) for our overall 2PNs biopsied during 2023 (38.2 mean age). No differences found. Out of the 14 diploid 3PNs, 28.6% (n = 4) were euploid, showing no differences with our 2023 euploidy rate. Two diploid 3PNs were mosaic, resulting in a total of 6 embryos that could potentially be transferred. Limitations, reasons for caution This study is limited by the number of triploid embryos recruited. As blastocyst rate for 3PNs population is lower than observed in the 2PN population the number of biopsied embryos is reduced. Euploidy rates for 3PNs and 2PNs are very similar, but the mean age differs by 2 years. Wider implications of the findings It is very important to distinguish between both types of 3PNs observed: PT are not worthy to keep and analyse, while MT embryos are very likely to be diploid, and it is worthwhile to culture and analyse them. Patients with few embryos available in particular could benefit from this study. Trial registration number not applicable

An overview of next generation sequencing strategies and genomics tools used for tuberculosis research.

Tuberculosis (TB) is a grave public health concern and is considered the foremost contributor to human mortality resulting from infectious disease. Due to the stringent clonality and extremely restricted genomic diversity, conventional methods prove inefficient for in-depth exploration of minor genomic variations and the evolutionary dynamics operating in Mycobacterium tuberculosis (M.tb) populations. Until now, the majority of reviews have primarily focused on delineating the application of whole-genome sequencing (WGS) in predicting antibiotic resistant genes, surveillance of drug resistance strains, and M.tb lineage classifications. Despite the growing use of next generation sequencing (NGS) and WGS analysis in TB research, there are limited studies that provide a comprehensive summary of there role in studying macroevolution, minor genetic variations, assessing mixed TB infections, and tracking transmission networks at an individual level. This highlights the need for systematic effort to fully explore the potential of WGS and its associated tools in advancing our understanding of TB epidemiology and disease transmission. We delve into the recent bioinformatics pipelines and NGS strategies that leverage various genetic features and simultaneous exploration of host-pathogen protein expression profile to decipher the genetic heterogeneity and host-pathogen interaction dynamics of the M.tb infections. This review highlights the potential benefits and limitations of NGS and bioinformatics tools and discusses their role in TB detection and epidemiology. Overall, this review could be a valuable resource for researchers and clinicians interested in NGS-based approaches in TB research.

Assessment of performance and comparison of three commercial HDV RNA detection assays: implications for diagnosis and treatment monitoring.

Precise HDV-RNA detection and quantification are pivotal for diagnosis and monitoring of response to newly approved treatment. We evaluate the performance of three HDV RNA detection and quantification assays. Hepatitis Delta RT-PCR system kit, EurobioPlex HDV assay, and RoboGene HDV RNA Quantification kit 2.0 were used for testing 151 HBsAg-positive samples, 90 HDV-RNA negative and 61 HDV-RNA positive. We also evaluated serial dilutions of the WHO international standard for HDV, PEI 7657/12. All HDV-RNA positive samples were genotyped using a next-generation sequencing strategy. Qualitative results indicated a 100% concordance between tests. Quantitative results correlated well, r2 = 0.703 (Vircell-vs-Eurobio), r2 = 0.833 (Vircell-vs-RoboGene), r2 = 0.835 (Robogene-vs-Eurobio). Bias index was 2.083 (Vircell-vs-Eurobio), -1.283 (Vircell-vs-RoboGene), and -3.36 (Robogene-vs-Eurobio). Using the WHO IS, Vircell overestimated the viral load by 0.98 log IU/mL, Eurobio by 1.46 log IU/mL, and RoboGene underestimated it by 0.98 log IU/mL. Fifty-nine samples were successfully genotyped (Genotype 1, n=52; Genotype 5, n=7; Genotype 6, n=1), with similar results for correlation and bias. This study underscores the necessity of using reliable HDV-RNA detection and quantification assays, as evidenced by the high concordance rates in qualitative detection and the observed variability in quantitative results. These findings highlight the importance of consistent assay use in clinical practice to ensure accurate diagnosis and effective treatment monitoring of HDV infection.

NGS-based stratification refines the risk stratification in T-ALL and identifies a very-high-risk subgroup of patients

AbstractWe previously reported a better outcome in adult and pediatric T-cell acute lymphoblastic leukemia (T-ALL) harboring NOTCH1 and/or FBXW7 mutations without alterations of K-N-RAS and PTEN genes. Availability of high-throughput next-generation sequencing (NGS) strategies led us to refine the outcome prediction in T-ALL. Targeted whole-exome sequencing of 72 T-ALL–related oncogenes was performed in 198 adults with T-ALLs in first remission from the GRAALL-2003/2005 protocols and 242 pediatric patients with T-ALLs from the FRALLE2000T. This approach enabled the identification of, to our knowledge, the first NGS-based classifier in T-ALL, categorizing low-risk patients as those with N/F, PHF6, or EP300 mutations, excluding N-K-RAS, PI3K pathway (PTEN, PIK3CA, and PIK3R1), TP53, DNMT3A, IDH1/2, and IKZF1 alterations, with a 5-year cumulative incidence of relapse (CIR) estimated at 21%. Conversely, the remaining patients were classified as high risk, exhibiting a 5-year CIR estimated at 47%. We externally validated this stratification in the pediatric cohort. NGS-based classifier was highly prognostic independently of minimal residual disease (MRD) and white blood cell (WBC) counts, in both adult and pediatric cohorts. Integration of the NGS-based classifier into a comprehensive risk-stratification model, including WBC count at diagnosis and MRD at the end of induction, enabled the identification of an adverse-risk subgroup (25%) with a 5-year CIR estimated at 51%, and a favorable-risk group (32%) with a 5-year CIR estimated at 12%. NGS-based stratification combined with WBC and MRD sharpens the prognostic classification in T-ALL and identifies a new subgroup of patients who may benefit from innovative therapeutic approaches. The GRAALL-2003/2005 studies were registered at www.ClinicalTrials.gov as #NCT00222027 and #NCT00327678.

Successive next-generation sequencing strategy for optimal fusion gene detection in non-small-cell lung cancer in clinical practice

Metastatic non-small-cell lung cancer (NSCLC) displays various molecular alterations in the RAS-MAPK pathway. In particular, NSCLCs show high rates of targetable gene fusion in ALK, RET, ROS1, NRG1 and NTRK, or MET exon 14 skipping. Rapid and accurate detection of gene fusion in EGFR/KRAS/BRAF mutations is important for treatment selection especially for first-line indications. RNA-based next-generation sequencing (NGS) panels appear to be the most appropriate as all targets are multiplexed in a single run. While comprehensive NGS panels remain costly for daily practice, optimal sequencing strategies using targeted DNA/RNA panel approaches need to be validated. Here, we describe our lung cancer screening strategy using DNA and RNA targeted approaches in a real-life cohort of 589 NSCLC patients assessed for molecular testing. Gene fusions were analysed in 174 patients negative for oncogene driver mutations or ALK immunohistochemistry in a two-step strategy. Targetable alterations were identified in 28% of contributive samples. Non-smokers had a 63.7% probability to have a targetable alteration as compared to 21.5% for smokers. Overall survival was significantly higher (p=0.03) for patients who received a molecularly matched therapy. Our study shows the feasibility in routine testing of NSCLC DNA/RNA molecular screening for all samples in a cost- and time-controlled manner. The significant high fusion detection rate in patients with wild-type RAS-MAPK tumours highlights the importance of amending testing strategies in NSCLC.

High-Throughput Genomics Identify Novel FBN1/2 Variants in Severe Neonatal Marfan Syndrome and Congenital Heart Defects.

Fibrillin-1 and fibrillin-2, encoded by FBN1 and FBN2, respectively, play significant roles in elastic fiber assembly, with pathogenic variants causing a diverse group of connective tissue disorders such as Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCD). Different genomic variations may lead to heterogeneous phenotypic features and functional consequences. Recent high-throughput sequencing modalities have allowed detection of novel variants that may guide the care for patients and inform the genetic counseling for their families. We performed clinical phenotyping for two newborn infants with complex congenital heart defects. For genetic investigations, we employed next-generation sequencing strategies including whole-genome Single-Nucleotide Polymorphism (SNP) microarray for infant A with valvular insufficiency, aortic sinus dilatation, hydronephrosis, and dysmorphic features, and Trio whole-exome sequencing (WES) for infant B with dextro-transposition of the great arteries (D-TGA) and both parents. Infant A is a term male with neonatal marfanoid features, left-sided hydronephrosis, and complex congenital heart defects including tricuspid regurgitation, aortic sinus dilatation, patent foramen ovale, patent ductus arteriosus, mitral regurgitation, tricuspid regurgitation, aortic regurgitation, and pulmonary sinus dilatation. He developed severe persistent pulmonary hypertension and worsening acute hypercapnic hypoxemic respiratory failure, and subsequently expired on day of life (DOL) 10 after compassionate extubation. Cytogenomic whole-genome SNP microarray analysis revealed a deletion within the FBN1 gene spanning exons 7-30, which overlapped with the exon deletion hotspot region associated with neonatal Marfan syndrome. Infant B is a term male prenatally diagnosed with isolated D-TGA. He required balloon atrial septostomy on DOL 0 and subsequent atrial switch operation, atrial septal defect repair, and patent ductus arteriosus ligation on DOL 5. Trio-WES revealed compound heterozygous c.518C>T and c.8230T>G variants in the FBN2 gene. Zygosity analysis confirmed each of the variants was inherited from one of the parents who were healthy heterozygous carriers. Since his cardiac repair at birth, he has been growing and developing well without any further hospitalization. Our study highlights novel FBN1/FBN2 variants and signifies the phenotype-genotype association in two infants affected with complex congenital heart defects with and without dysmorphic features. These findings speak to the importance of next-generation high-throughput genomics for novel variant detection and the phenotypic variability associated with FBN1/FBN2 variants, particularly in the neonatal period, which may significantly impact clinical care and family counseling.

The Polymorphism Analysis of HLA Class II Alleles Based on Next-Generation Sequencing and Prevention Strategy for Allele Dropout

To investigate the accuracy of next-generation sequencing technology (NGS) in detecting the polymorphisms of HLA-DRB1, DQB1, DQA1, DRB3, DRB4, DRB5, DPA1 and DPB1 alleles in randomly-selected unrelated healthy individuals from Shenzhen Han population, investigate the potential reason for HLA-DRB1 allele dropout in routine NGS, and establish an internal quality control system. NGS-based HLA class II genotyping was performed on 1 012 samples using the MiSeqDxTM platform. The suspected missed alleles indicated by the quality control software and HLA-DRB1 homozygotes were confirmed by PCR-SSOP or PCR-SBT methods. A total of 139 alleles were detected, including HLA-DRB1(45), DRB3(7), DRB4(5), DRB5(7), DQA1(17), DQB1(21), DPA1(10) and DPB1(27). HLA-DRB1*09:01(17.09%),15:01(10.72%); DRB3*02:02(25.99%),03:01(10.18%); DRB4*01:03(36.46%); DRB5*01:01(15.42%); DQA1*01:02(20.01%),03:02(17.19%); DQB1*03:01(19.47%),03:03(17.98%), 05:02(11.66%), 06:01(10.67%); DPA1*02:02(54.45%), 01:03(31.18%) and DPB1*05:01(39.13%), 02:01(16.90%) alleles were the most common alleles in Shenzhen Han population (frequencies >10%). There was no statistical difference between the gene frequencies of HLA-DRB1 and DQB1 loci in our study. The HLA Common and Well-Documented Alleles in China (CWD2.4) (χ2=12.68, P >0.05). 94 cases of HLA-DRB1 homozygous samples detected by NGS were retested by PCR-SSOP or SBT method, and one case of allele dropout at HLA-DRB1 locus was found. SBT method confirmed that the allele of DRB1*04:03 was missed. The laboratory internal quality control system was established. Two cases of new alleles were detected and named by WHO Nomenclature Committee for Factors of the HLA System. The HLA genotyping results based on NGS showed a significantly lower ambiguity rate. The HLA class II alleles exhibit genetic polymorphism in the Han population of unrelated healthy individuals in Shenzhen. The independent method based on NGS in clinical histocompatibility testing has limitations and requires internal quality control strategies to avoid allele-dropout events.

Cost of genetic testing, delayed care, and suboptimal treatment associated with polymerase chain reaction versus next-generation sequencing biomarker testing for genomic alterations in metastatic non-small cell lung cancer

Aims To assess US payers’ per-patient cost of testing associated with next-generation sequencing (NGS) versus polymerase chain reaction (PCR) biomarker testing strategies among patients with metastatic non-small cell lung cancer (mNSCLC), including costs of testing, delayed care, and suboptimal treatment initiation. Methods A decision tree model considered biomarker testing for genomic alterations using either NGS, sequential PCR testing, or hotspot panel PCR testing. Literature-based model inputs included time-to-test results, costs for testing/medical care, costs of delaying care, costs of immunotherapy [IO]/chemotherapy [CTX] initiation prior to receiving test results, and costs of suboptimal treatment initiation after test results (i.e. costs of first-line IO/CTX in patients with actionable mutations that were undetected by PCR that would have been identified with NGS). The proportion of patients testing positive for a targetable alteration, time to appropriate therapy initiation, and per-patient costs were estimated for NGS and PCR strategies combined. Results In a modeled cohort of 1,000,000 members (25% Medicare, 75% commercial), an estimated 1,119 had mNSCLC and received testing. The proportion of patients testing positive for a targetable alteration was 45.9% for NGS and 40.0% for PCR testing. Mean per-patient costs were lowest for NGS ($8,866) compared to PCR ($18,246), with lower delayed care costs of $1,301 for NGS compared to $3,228 for PCR, and lower costs of IO/CTX initiation prior to receiving test results (NGS: $2,298; PCR:$5,991). Cost savings, reaching $10,496,220 at the 1,000,000-member plan level, were driven by more rapid treatment with appropriate therapy for patients tested with NGS (2.1 weeks) compared to PCR strategies (5.2 weeks). Limitations Model inputs/assumptions were based on published literature or expert opinion. Conclusions NGS testing was associated with greater cost savings versus PCR, driven by more rapid results, shorter time to appropriate therapy initiation, and minimized use of inappropriate therapies while awaiting and after test results.

The genetic landscape of mitochondrial diseases in the next-generation sequencing era: a Portuguese cohort study.

Introduction: Rare disorders that are genetically and clinically heterogeneous, such as mitochondrial diseases (MDs), have a challenging diagnosis. Nuclear genes codify most proteins involved in mitochondrial biogenesis, despite all mitochondria having their own DNA. The development of next-generation sequencing (NGS) technologies has revolutionized the understanding of many genes involved in the pathogenesis of MDs. In this new genetic era, using the NGS approach, we aimed to identify the genetic etiology for a suspected MD in a cohort of 450 Portuguese patients. Methods: We examined 450 patients using a combined NGS strategy, starting with the analysis of a targeted mitochondrial panel of 213 nuclear genes, and then proceeding to analyze the whole mitochondrial DNA. Results and Discussion: In this study, we identified disease-related variants in 134 (30%) analyzed patients, 88 with nuclear DNA (nDNA) and 46 with mitochondrial DNA (mtDNA) variants, most of them being pediatric patients (66%), of which 77% were identified in nDNA and 23% in mtDNA. The molecular analysis of this cohort revealed 72 already described pathogenic and 20 novel, probably pathogenic, variants, as well as 62 variants of unknown significance. For this cohort of patients with suspected MDs, the use of a customized gene panel provided a molecular diagnosis in a timely and cost-effective manner. Patients who cannot be diagnosed after this initial approach will be further selected for whole-exome sequencing. Conclusion: As a national laboratory for the study and research of MDs, we demonstrated the power of NGS to achieve a molecular etiology, expanding the mutational spectrum and proposing accurate genetic counseling in this group of heterogeneous diseases without therapeutic options.

NGS-Based Stratification Refines the Risk Stratification in T-ALL and Identifies a Very High-Risk Subgroup of Patients

Purpose We previously reported a significantly better outcome in adult and pediatric T-cell acute lymphoblastic leukemia (T-ALL) harboring NOTCH1 and/or FBXW7 ( N/F) mutations without alterations of K-N-RAS and PTEN(R/P) genes . High-throughput next-generation sequencing strategies (NGS) allowed us to refine the prediction of outcome in T-ALL. Patients and Methods 198 adult T-ALLs in first remission (CR1) from the GRAALL-2003/2005 protocol were included in the study as the construction cohort, and 242 pediatric T-ALLs from FRALLE2000 were used as a validation cohort. Targeted whole-exome sequencing of 63 T-ALL-related oncogenes was performed. Primary outcome was cumulative incidence of relapse (CIR). To account for the large number of candidates genes, selection was performed using a LASSO penalization in a Fine and Gray model predicting CIR (Fu Z. et al. Lifetime Data Anal., 2017). To construct the final risk-stratification score, we used non-parametric clustering of CIR curves through k-medians algorithm (Villanueva N. et al. Stat. Med., 2019). Results We confirm the prognostic classifier NFRP in the NGS era and evaluate the impact of 39 new gene alterations in the adult cohort. Alterations affecting TP53, DNMT3A, IDH1/2, IKZF1, PI3K pathway ( PTEN, PIK3CA and PIK3R1), EP300, and PHF6 were independent prognostic factors in adult T-ALL. This led us to propose the first NGS-based classifier in T-ALL defining low risk patient (LR) as those with N/F, PHF6 or EP300 mutations without N-K-RAS, PI3K pathway , TP53, DNMT3A, IDH1/2 and IKZF1 alterations (234 of 440 patients, 53%). In the adult cohort, the NGS-based classifier separates a high-risk group (HR) (n=90/198, 45%) with a 5-year CIR of 47% (95%CI:36%-57%) and a low-risk group (LR) (n=108/198, 55%) with a 5-year CIR of 21% (95%CI:14%-29%) (p<0.0001). Our NGS-classifier was validated in the pediatric cohort, with a 5-year CIR of 35% (95%CI:26%-44%) in HR group (n=116/242, 48%) and 5-year CIR of 17% (95%CI:11%-24%) in the LR group (n=126/242, 52%) (p=0.001) ( Figure A). Since the NGS-based classifier is highly prognostic independently of minimal residual disease (MRD) at end of induction (cutoff 10 -4) and white blood cells count (WBC) (cutoff 100 x 10 9/L), we then developed and externally validated a global risk stratification model incorporating MRD1, WBC at diagnosis and the NGS-classifier. This model identifies 3 subgroups at CR1: a large favorable Risk (CR1-FAV) group (231/332, 70%) with CIR at 5 years estimated at 19% (95%CI:14%-24%) ( Figure B), a subgroup of Adverse risk (CR1-ADV) patients (30/332, 9%) with a 5-year CIR of 68% (95%CI:46%-82%) and an Intermediate risk (CR1-INT) group (71/332, 21%) with a 5-year CIR of 37% (95%CI:26%-48%). Conclusion T-ALL NGS-based stratification combined with WBC and MRD evaluation sharpens the prognostic classification in T-ALL and identifies a new subgroup of adverse risk patients who should benefit from innovative therapeutic approaches.

DNA-pools targeted-sequencing as a robust cost-effective method to detect rare variants: Application to dilated cardiomyopathy genetic diagnosis.

Dilated cardiomyopathy (DCM) is a heart disease characterized by left ventricular dilatation and systolic dysfunction. In 30% of cases, pathogenic variants, essentially private to each patient, are identified in at least one of almost 50 reported genes. Thus, while costly, exons capture-based Next Generation Sequencing (NGS) of a targeted gene panel appears as the best strategy to genetically diagnose DCM. Here, we report a NGS strategy applied to pools of 8 DNAs from DCM patients and validate its robustness for rare variants detection at 4-fold reduced cost. Our pipeline uses Freebayes to detect variants with the expected 1/16 allele frequency. From the whole set of detected rare variants in 96 pools we set the variants quality parameters optimizing true positives calling. When compared to simplex DNA sequencing in a shared subset of 50 DNAs, 96% of SNVs/InsDel were accurately identified in pools. Extended to the 384 DNAs included in the study, we detected 100 variants (ACMG class 4 and 5), mostly in well-known morbid gene causing DCM such as TTN, MYH7, FLNC, and TNNT2. To conclude, we report an original pool-sequencing NGS method accurately detecting rare variants. This innovative approach is cost-effective for genetic diagnostic in rare diseases.

A unified DNA- and RNA-based NGS strategy for the analysis of multiple types of variants at the dual nucleic acid level in solid tumors.

Targeted next-generation sequencing (NGS) is a powerful and suitable approach to comprehensively identify multiple types of variants in tumors. RNA-based NGS is increasingly playing an important role in precision oncology. Both parallel and sequential DNA- and RNA-based approaches are expensive, burdensome, and have long turnaround times, which can be impractical in clinical practice. A streamlined, unified DNA- and RNA-based NGS approach is urgently needed in clinical practice. A DNA/RNA co-hybrid capture sequencing (DRCC-Seq) approach was designed to capture pre-capture DNA and RNA libraries in a single tube and convert them into one NGS library. The performance of the DRCC-Seq approach was evaluated by a panel of reference standards and clinical samples. The average depth, DNA data ratio, capture ratio, and target coverage 250 (×) of the DNA panel data had a negative correlation with an increase in the proportion of RNA probes. The SNVs, indels, fusions, and MSI status were not affected by the proportion of RNA probes, but the copy numbers of the target genes were higher than expected in the standard materials, and many unexpected gene amplifications were found using D:R (1:2) and D:R (1:4) probe panels. The optimal ratio of DNA and RNA probes in the combined probe panel was 1:1 using the DRCC-Seq approach. The DRCC-Seq approach was feasible and reliable for detecting multiple types of variants in reference standards and real-world clinical samples. The DRCC-Seq approach is more cost-effective, with a shorter turnaround time and lower labor requirements than either parallel or sequential targeted DNA NGS and RNA NGS. It is feasible to identify multiple genetic variations at the DNA and RNA levels simultaneously in clinical practice.

Calibration of cell-free DNA measurements by next-generation sequencing.

Accurate monitoring of disease burden depends on accurate disease marker quantification. Although next-generation sequencing (NGS) is a promising technology for noninvasive monitoring, plasma cell-free DNA levels are often reported in misleading units that are confounded by non-disease-related factors. We proposed a novel strategy for calibrating NGS assays using spiked normalizers to improve precision and to promote standardization and harmonization of analyte concentrations. In this study, we refined our NGS protocol to calculate absolute analyte concentrations to (1) adjust for assay efficiency, as judged by recovery of spiked synthetic normalizer DNAs, and (2) calibrate NGS values against droplet digital polymerase chain reaction (ddPCR). As a model target, we chose the Epstein-Barr virus (EBV) genome. In patient (n = 12) and mock (n = 12) plasmas, NGS and 2 EBV ddPCR assays were used to report EBV load in copies per mL of plasma. Next-generation sequencing was equally sensitive to ddPCR, with improved linearity when NGS values were normalized for spiked DNA read counts (R2 = 0.95 for normalized vs 0.91 for raw read concentrations). Linearity permitted NGS calibration to each ddPCR assay, achieving equivalent concentrations (copies/mL). Our novel strategy for calibrating NGS assays suggests potential for a universal reference material to overcome biological and preanalytical variables hindering traditional NGS strategies for quantifying disease burden.

Abstract 268: Antitumor CD4+ T cells reprogram tumor metabolism to drive progressive tumor regression

Abstract Adoptive cell therapy has revolutionized the landscape of cancer immunotherapy, exhibiting unprecedented success in treating various types of cancer. Substantial investigative efforts have been devoted to gaining a deeper understanding of the ways in which adoptively transferred T cells eliminate tumors and to discovering strategies that enhance T cell functionality in the tumor microenvironment. We have established an experimental mouse model in which adoptive transfer of tumor-specific CD4+ T cells leads to eradication of established tumors. Using this model, we previously reported on the profound disruption of tumor metabolism induced by adoptive T cell therapy. However, the detailed mechanisms that enable tumor-reactive CD4+ T cells to alter tumor metabolism remain largely undefined. In the current study, we aimed to identify the key metabolic enzymes and pathways targeted by antitumor CD4+ T cells that lead to progressive tumor regression. Utilizing next-generation sequencing strategies, including bulk and single-cell RNA sequencing, we examined the metabolic changes cancer cells undergo in response to treatment, and the immune cell compositions in the tumor microenvironment. Additionally, we performed an in vivo CRISPR knockout screen to identify the metabolic genes that either sensitize tumor cells to adoptive cell therapy or contribute to tumor resistance. Results from our study may also illuminate potential targets in cancer metabolism that can be exploited using small-molecule inhibitors when adoptive cell therapy is not feasible. Citation Format: Caitlin Brandle, Ogacheko D. Okoko, Md Yeashin Gazi, Xin Wang, Mercy Kehinde-Ige, Huidong Shi, Gang Zhou. Antitumor CD4+ T cells reprogram tumor metabolism to drive progressive tumor regression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 268.

Cost Savings of Expedited Care with Upfront Next-Generation Sequencing Testing versus Single-Gene Testing among Patients with Metastatic Non-Small Cell Lung Cancer Based on Current Canadian Practices.

This study assessed the total costs of testing, including the estimated costs of delaying care, associated with next-generation sequencing (NGS) versus single-gene testing strategies among patients with newly diagnosed metastatic non-small cell lung cancer (mNSCLC) from a Canadian public payer perspective. A decision tree model considered testing for genomic alterations using tissue biopsy NGS or single-gene strategies following Canadian guideline recommendations. Inputs included prevalence of mNSCLC, the proportion that tested positive for each genomic alteration, rebiopsy rates, time to test results, testing/medical costs, and costs of delaying care based on literature, public data, and expert opinion. Among 1,000,000 hypothetical publicly insured adult Canadians (382 with mNSCLC), the proportion of patients that tested positive for a genomic alteration with an approved targeted therapy was 38.0% for NGS and 26.1% for single-gene strategies. The estimated mean time to appropriate targeted therapy initiation was 5.1 weeks for NGS and 9.2 weeks for single-gene strategies. Based on literature, each week of delayed care cost CAD 406, translating to total mean per-patient costs of CAD 3480 for NGS and CAD 5632 for single-gene strategies. NGS testing with mNSCLC in current Canadian practice resulted in more patients with an identified mutation, shorter time to appropriate targeted therapy initiation, and lower total testing costs compared to single-gene strategies.

Study of Ubiquitin Pathway Genes in a French Population with Amyotrophic Lateral Sclerosis: Focus on HECW1 Encoding the E3 Ligase NEDL1.

The ubiquitin pathway, one of the main actors regulating cell signaling processes and cellular protein homeostasis, is directly involved in the pathophysiology of amyotrophic lateral sclerosis (ALS). We first analyzed, by a next-generation sequencing (NGS) strategy, a series of genes of the ubiquitin pathway in two cohorts of familial and sporadic ALS patients comprising 176 ALS patients. We identified several pathogenic variants in different genes of this ubiquitin pathway already described in ALS, such as FUS, CCNF and UBQLN2. Other variants of interest were discovered in new genes studied in this disease, in particular in the HECW1 gene. We have shown that the HECT E3 ligase called NEDL1, encoded by the HECW1 gene, is expressed in neurons, mainly in their somas. Its overexpression is associated with increased cell death in vitro and, very interestingly, with the cytoplasmic mislocalization of TDP-43, a major protein involved in ALS. These results give new support for the role of the ubiquitin pathway in ALS, and suggest further studies of the HECW1 gene and its protein NEDL1 in the pathophysiology of ALS.

Model organisms for functional validation in genetic renal disease.

Functional validation is key for establishing new disease genes in human genetics. Over the years, model organisms have been utilized in a very effective manner to prove causality of genes or genetic variants for a wide variety of diseases. Also in hereditary renal disease, model organisms are very helpful for functional validation of candidate genes and variants identified by next-generation sequencing strategies and for obtaining insights into the pathophysiology. Due to high genetic conservation as well as high anatomical and physiological similarities with the human kidney, almost all genetic kidney diseases can be studied in the mouse. However, mouse work is time consuming and expensive, so there is a need for alternative models. In this review, we will provide an overview of model organisms used in renal research, focusing on mouse, zebrafish, frog, and fruit flies.

From the patient to the population: Use of genomics for population screening.

Genomic medicine is expanding from a focus on diagnosis at the patient level to prevention at the population level given the ongoing under-ascertainment of high-risk and actionable genetic conditions using current strategies, particularly hereditary breast and ovarian cancer (HBOC), Lynch Syndrome (LS) and familial hypercholesterolemia (FH). The availability of large-scale next-generation sequencing strategies and preventive options for these conditions makes it increasingly feasible to screen pre-symptomatic individuals through public health-based approaches, rather than restricting testing to high-risk groups. This raises anew, and with urgency, questions about the limits of screening as well as the moral authority and capacity to screen for genetic conditions at a population level. We aimed to answer some of these critical questions by using the WHO Wilson and Jungner criteria to guide a synthesis of current evidence on population genomic screening for HBOC, LS, and FH.

Highly diverse ribonucleic acid viruses in the viromes of eukaryotic host species in Yunnan province, China.

BackgroundThe diversity in currently documented viruses and their morphological characteristics indicates the need for understanding the evolutionary characteristics of viruses. Notably, further studies are needed to obtain a comprehensive landscape of virome, the virome of host species in Yunnan province, China.Materials and methodsWe implemented the metagenomic next-generation sequencing strategy to investigate the viral diversity, which involved in 465 specimens collected from bats, pangolins, monkeys, and other species. The diverse RNA viruses were analyzed, especially focusing on the genome organization, genetic divergence and phylogenetic relationships.ResultsIn this study, we investigated the viral composition of eight libraries from bats, pangolins, monkeys, and other species, and found several diverse RNA viruses, including the Alphacoronavirus from bat specimens. By characterizing the genome organization, genetic divergence, and phylogenetic relationships, we identified five Alphacoronavirus strains, which shared phylogenetic association with Bat-CoV-HKU8-related strains. The pestivirus-like virus related to recently identified Dongyang pangolin virus (DYPV) strains from dead pangolin specimens, suggesting that these viruses are evolving. Some genomes showed higher divergence from known species (e.g., calicivirus CS9-Cali-YN-CHN-2020), and many showed evidence of recombination events with unknown or known strains (e.g., mamastroviruses BF2-astro-YN-CHN-2020 and EV-A122 AKM5-YN-CHN-2020). The newly identified viruses showed extensive changes and could be assigned as new species, or even genus (e.g., calicivirus CS9-Cali-YN-CHN-2020 and iflavirus Ifla-YN-CHN-2020). Moreover, we identified several highly divergent RNA viruses and estimated their evolutionary characteristics among different hosts, providing data for further examination of their evolutionary dynamics.ConclusionOverall, our study emphasizes the close association between emerging viruses and infectious diseases, and the need for more comprehensive surveys.