Next-generation Sequencing Technologies Research Articles

Molecular characterization of the whole genome of H9N2 avian influenza virus isolated from Egyptian poultry farms.

H9N2 avian influenza viruses (AIVs) affect both poultry and humans on a global level, and they are especially prevalent in Egypt. In this study, we sequenced the entire genome of AIV H9N2 isolated from chickens in Egypt in 2021, using next-generation sequencing (NGS) technology. Phylogenetic analysis of the resulting sequences showed that the studied strain was generally monophyletic and grouped within the G1 sublineage of the Eurasian lineage. Four segments (polymerase basic 2 [PB2], polymerase basic 1 [PB1], polymerase acidic [PA], and non-structural [NS]) were related to Egyptian genotype II, while the nucleoprotein (NP), neuraminidase (NA), matrix (M), and haemagglutinin (HA) segments were related to Egyptian genotype I. Molecular analysis revealed that HA protein contained amino acid residues (191H and 234L) that suggested a predilection for attaching to human-like receptors. The antigenic sites of HA had two nonsynonymous mutations: V194I at antigenic site A and M40K at antigenic site B. Furthermore, the R403W and S372A mutations, which have been observed in H3N2 and H2N2 strains that caused human pandemics, were found in the NA protein of the detected strain. The internal proteins contained virulence markers: 504V in the PB2 protein, 622G, 436Y, 207K, and 677T in the PB1 protein, 127V, 550L, and 672L in PA protein, and 64F and 69P in the M protein. These results show that the detected strain had undergone intrasubtype reassortment. Furthermore, it contains changes in the viral proteins that make it more likely to be virulent, raising a question about the tendency of AIV H9N2 to become highly pathogenic in the future for both poultry and humans.

Mutation landscape in Chinese nodal diffuse large B-cell lymphoma by targeted next generation sequencing and their relationship with clinicopathological characteristics

BackgroundDiffuse large B-cell lymphoma (DLBCL), an aggressive and heterogenic malignant entity, is still a challenging clinical problem, since around one-third of patients are not cured with primary treatment. Next-generation sequencing (NGS) technologies have revealed common genetic mutations in DLBCL. We devised an NGS multi-gene panel to discover genetic features of Chinese nodal DLBCL patients and provide reference information for panel-based NGS detection in clinical laboratories.MethodsA panel of 116 DLBCL genes was designed based on the literature and related databases. We analyzed 96 Chinese nodal DLBCL biopsy specimens through targeted sequencing.ResultsThe most frequently mutated genes were KMT2D (30%), PIM1 (26%), SOCS1 (24%), MYD88 (21%), BTG1 (20%), HIST1H1E (18%), CD79B (18%), SPEN (17%), and KMT2C (16%). SPEN (17%) and DDX3X (6%) mutations were highly prevalent in our study than in Western studies. Thirty-three patients (34%) were assigned as genetic classification by the LymphGen algorithm, including 12 cases MCD, five BN2, seven EZB, seven ST2, and two EZB/ST2 complex. MYD88 L265P mutation, TP53 and BCL2 pathogenic mutations were unfavorable prognostic biomarkers in DLBCL.ConclusionsThis study presents the mutation landscape in Chinese nodal DLBCL, highlights the genetic heterogeneity of DLBCL and shows the role of panel-based NGS to prediction of prognosis and potential molecular targeted therapy in DLBCL. More precise genetic classification needs further investigations.

Screening for thalassemia carriers among the Han population of childbearing age in Southwestern of China

Purpose:Thalassemia is a severe hereditary blood disorder that poses a significant threat to human health and leads to mortality and disability. It is one of the most prevalent monogenic diseases worldwide. The aim of this study was to analyze the molecular epidemiological data of individuals of childbearing age from the Han ethnic group with thalassemia in Southwest China and to explore the application of next-generation sequencing (NGS) technology in screening thalassemia carriers.Methods:The participants were Han males and females of childbearing age who sought medical advice at the West China Second University Hospital, Sichuan University from June 2022 to June 2023. We detected α- and β-thalassemia mutations using full-length capture of the thalassemia genes and NGS technology.Results:In a cohort of 1,093 participants, 130 thalassemia carriers were identified, with an overall detection rate of 11.89% (130/1,093). Among these, 0.91% (10/1,093) had mutations that could not be detected using traditional PCR techniques. The proportions of carriers with α-, β-, and α-complexed β-thalassemia gene mutations were 7.68% (84/1,093), 3.93% (43/1,093), and 0.27% (3/1,093), respectively. We identified a novel HBA2 c.166del variant that has not been previously reported.Conclusion:Using NGS technology, we found that the mutation-carrying rate of thalassemia genes was 11.89% in the Han population of childbearing age in Southwest China. Compared with the results of traditional PCR techniques, NGS detected an additional 0.91% (10/1,093) rare genetic variants. NGS technology should be utilized as the primary screening method for thalassemia carriers among Han nationality people of childbearing age in Southwest China.

Revisit and explore the ethylene-independent mechanism of sex expression in cucumber (Cucumis sativus).

This review provides a thorough and comprehensive perspective on the topic of cucumber sexual expression. Specifically, insights into sex expression mediated by pathways other than ethylene are highlighted. Cucumber (Cucumis sativus L.) is a common and important commercial crop that is cultivated and consumed worldwide. Additionally, this species is commonly used as a model for investigating plant sex expression. Cucumbers exhibit a variety of floral arrangements, comprising male, female, and hermaphroditic (bisexual) flowers. Generally, cucumber plants that produce female flowers are typically preferred due to their significant impact on the overall output. Various environmental conditions, such as temperature, light quality, and photoperiod, have been also shown to influence the sex expression in this species. Multiple lines of evidence indicate that ethylene and its biosynthesis genes are crucial in regulating cucumber sex expression. Gibberellins, another well-known phytohormone, can similarly influence cucumber sex expression via an ethylene-independent route. Further studies employing the next-generation sequencing technology also visualized a deeper slice of the molecular mechanism such as the role of the cell cycle program in the cucumber sex expression. This review aims to provide an overview of the sex expression of cucumber including its underlying molecular mechanism and regulatory aspects based on recent investigations.

Integrated Untargeted Metabolome, Full-Length Sequencing and Transcriptome Analyses Reveal the Mechanism of Flavonoid Biosynthesis in Blueberry (Vaccinium spp.) Fruit

As a highly economic berry fruit crop, blueberry is enjoyed by most people and has various potential health benefits, many of which are attributed to the relatively high concentrations of flavonoids. To obtain more accurate and comprehensive transcripts, the full-length transcriptome of half-highbush blueberry (Vaccinium corymbosum/angustifolium cultivar Northland) obtained using single molecule real-time and next-generation sequencing technologies was reported for the first time. Overall, 147,569 consensus transcripts (average length, 2738 bp; N50, 3176 bp) were obtained. After quality control steps, 63,425 high-quality isoforms were obtained and 5030 novel genes, 3002 long non-coding RNAs, 3946 transcription factor genes (TFs), 30,540 alternative splicing events, and 2285 fusion gene pairs were identified. To better explore the molecular mechanism of flavonoid biosynthesis in mature blueberry fruit, an integrative analysis of the metabolome and transcriptome was performed on the exocarp, sarcocarp, and seed. A relatively complete biosynthesis pathway map of phenylpropanoids, flavonoids, and proanthocyanins in blueberry was constructed. The results of the joint analysis showed that the 228 functional genes and 42 TFs regulated 78 differentially expressed metabolites within the biosynthesis pathway of phenylpropanoids/flavonoids. O2PLS analysis results showed that the key metabolites differentially accumulated in blueberry fruit tissues were albireodelphin, delphinidin 3,5-diglucoside, delphinidin 3-O-rutinoside, and delphinidin 3-O-sophoroside, and 10 structural genes (4 Vc4CLs, 3 VcBZ1s, 1 VcUGT75C1, 1 VcAT, and 1 VcUGAT), 4 transporter genes (1 VcGSTF and 3 VcMATEs), and 10 TFs (1 VcMYB, 2 VcbHLHs, 4 VcWD40s, and 3 VcNACs) exhibited strong correlations with 4 delphinidin glycosides. These findings provide insights into the molecular mechanisms of flavonoid biosynthesis and accumulation in blueberry fruit.

The application value of metagenomic next-generation sequencing technology in the diagnosis and treatment of neonatal infectious meningitis – a single center retrospective case-control study

ABSTRACT Objective This retrospective study was conducted to investigate the application value of metagenomics next generation sequencing (mNGS) technology in the diagnosis and treatment of neonatal infectious meningitis. Methods From 1 January 2020 to 31 December 2022, 73 newborns suspected of infectious meningitis were hospitalized. After screening by inclusion and exclusion criteria, 69 newborns were subsequently included in the study, containing 27 cases with positive mNGS result and 42 cases with negative mNGS result. Furthermore, according to the diagnosis of meningitis, mNGS positive group and mNGS negative group were further divided into infectious meningitis with mNGS (+) group (n = 27) and infectious meningitis with mNGS (-) group (n = 26), respectively. Results (1) Compared with cerebrospinal fluid (CSF) culture, mNGS has better diagnostic value [positive predictive value (PPV) = 100.00% (27/27), negative predictive value (NPV) = 38.10% (16/42), agreement rate = 62.32% (43/69), area under the curve (AUC) = 0.750, 95% confidence interval (CI): 0.636–0.864]. (2) There were significant differences in the onset age, age at first CSF test, CSF leukocyte count, CSF glucose, positive rate of CSF culture, blood leukocyte count, procalcitonin (PCT), C-reaction protein (CRP), age at first mNGS test and adjusting anti-infective medication in the comparison between infectious meningitis with mNGS (+) group and infectious meningitis with mNGS (-) group (p < 0.05). (3) mNGS could help improve the cure rate [crude odds ratio (OR) = 3.393, 95%CI: 1.072–10.737; adjusted OR = 15.580, 95%CI: 2.114–114.798]. Conclusion Compared with classic meningitis detection methods, mNGS has better PPV, NPV, agreement rate, and AUC. mNGS could help improve the cure rate.

The RAS-signaling-pathway-mutation-related prognosis in B-cell acute lymphoblastic leukemia: A report from South China children's leukemia group.

The next-generation sequencing technologies application discovers novel genetic alterations frequently in pediatric acute lymphoblastic leukemia (ALL). RAS signaling pathway mutations at the time of relapse ALL frequently appear as small subclones at the time of onset, which are considered as the drivers in ALL relapse. Whether subclones alterations in the RAS signaling pathway should be considered for risk group stratification of ALL treatment is not decided yet. In this work, we investigate the RAS signaling pathway mutation spectrum and the related prognosis in pediatric ALL. We employed an NGS panel comprising 220 genes. NGS results were collected from 202 pediatric ALL patients. 155 patients (76.7%) harbored at least one mutation. The incidences of RAS signaling pathway mutations are different significantly between T-ALL and B-ALL. In B-ALL, the RAS pathway is mostly involved, and NRAS (17.6%), KRAS (22.7%), and PTPN11 (7.7%) were the three most frequently mutated genes. Co-occurring mutations of CREBBP and NRAS, FLT3, or PTPN11 (p=0.002, p=0.009, and p=0.003, respectively) were found in this cohort. The 3-year RFS rates for the RAS signaling pathway mutation-positive and negative cases was 76.5 % versus 89.7 % (p=0.012). Four cases relapsed in the lately 3years were RAS signaling pathway mutation-positive. RAS signaling pathway mutation is an important biomarker for poorer relapse-free survival in pediatric B-ALL patients despite good early MRD levels.

An evolution of Nanopore next-generation sequencing technology: implications for medical microbiology and public health.

Next-generation sequencing has evolved as a powerful tool, with applications that extend from diagnosis to public health surveillance and outbreak investigations. Short-read sequencing, using primarily Illumina chemistry, has been the prevailing approach. Single-molecule sensing and long-read sequencing using Oxford Nanopore Technologies (ONT) has witnessed a breakthrough in the evolution of the technology, performance, and applications in the past few years. In this issue of the Journal of Clinical Microbiology, Bogaerts et al. (https://doi.org/10.1128/jcm.01576-23) describe the utility of the latest ONT sequencing technology, the R10.4.1, in bacterial outbreak investigations. The authors demonstrate that ONT R10.4.1 technology can be comparable to Illumina sequencing for single-nucleotide polymorphism-based phylogeny. The authors emphasize that the reproducibility between ONT and Illumina technologies could facilitate collaborations among laboratories utilizing different sequencing platforms for outbreak investigations.

A case of polyglucosan body myopathy caused by an RBCK1 gene variant and literature review.

To analyze the clinical and genetic characteristics of a patient with Polyglucosan body myopathy 1 (PGBM1) caused by a novel compound heterozygous variant in the RBCK1 gene. The clinical data of the patient were collected, next-generation sequencing technology was used to determine the exome sequence of the patient, and the suspected pathogenic locus was verified by Sanger sequencing. Through whole-exome sequencing, we found that there were c.919G>T; p. (Glu307*) and c.723_730dup; p. (Glu244fs) variants of the RBCK1 gene in the patient, inherited from his parents, constituting a compound heterozygous variation. According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), the two variants were rated as pathogenic, but there were no comparable cases. Previous literature reported 24 patients with RBCK1 gene variants, involving a total of 20 myocardial and 18 skeletal muscle cases. The patient was twice diagnosed with cardiac insufficiency, neglecting the usual manifestations of muscle weakness, resulting in misdiagnosis. Later, novel variants in the RBCK1 gene were discovered through whole-exome sequencing, and symptomatic treatment was given after diagnosis. The importance of whole-exome sequencing technology in disease diagnosis and genetic counseling was emphasized.

Global insights into endophytic bacterial communities of terrestrial plants: Exploring the potential applications of endophytic microbiota in sustainable agriculture

Endophytic microorganisms are indispensable symbionts during plant growth and development and often serve functions such as growth promotion and stress resistance in plants. Therefore, an increasing number of researchers have applied endophytes for multifaceted phytoremediation (e.g., organic pollutants and heavy metals) in recent years. With the availability of next-generation sequencing technologies, an increasing number of studies have shifted the focus from culturable bacteria to total communities. However, information on the composition, structure, and function of bacterial endophytic communities is still not widely synthesized. To explore the general patterns of variation in bacterial communities between plant niches, we reanalyzed data from 1499 samples in 30 individual studies from different continents and provided comprehensive insights. A group of bacterial genera were commonly found in most plant roots and shoots. Our analysis revealed distinct variations in the diversity, composition, structure, and function of endophytic bacterial communities between plant roots and shoots. These variations underscore the sophisticated mechanisms by which plants engage with their endophytic microbiota, optimizing these interactions to bolster growth, health, and resilience against stress. Highlighting the strategic role of endophytic bacteria in promoting sustainable agricultural practices and environmental stewardship, our study not only offers global insights into the endophytic bacterial communities of terrestrial plants but also underscores the untapped potential of these communities as invaluable resources for future research.

Development, testing and validation of a targeted NGS-panel for the detection of actionable mutations in lung cancer (NSCLC) using anchored multiplex PCR technology in a multicentric setting.

Lung cancer is a paradigm for a genetically driven tumor. A variety of drugs were developed targeting specific biomarkers requiring testing for tumor genetic alterations in relevant biomarkers. Different next-generation sequencing technologies are available for library generation: 1) anchored multiplex-, 2) amplicon based- and 3) hybrid capture-based-PCR. Anchored multiplex PCR-based sequencing was investigated for routine molecular testing within the national Network Genomic Medicine Lung Cancer (nNGM). Four centers applied the anchored multiplex ArcherDX-Variantplex nNGMv2 panel to re-analyze samples pre-tested during routine diagnostics. Data analyses were performed by each center and compiled centrally according to study design. Pre-defined standards were utilized, and panel sensitivity was determined by dilution experiments. nNGMv2 panel sequencing was successful in 98.9% of the samples (N = 90). With default filter settings, all but two potential MET exon 14 skipping variants were identified at similar allele frequencies. Both MET variants were found with an adapted calling filter. Three additional variants (KEAP1, STK11, TP53) were called that were not identified in pre-testing analyses. Only total DNA amount but not a qPCR-based DNA quality score correlated with average coverage. Analysis was successful with a DNA input as low as 6.25ng. Anchored multiplex PCR-based sequencing (nNGMv2) and a sophisticated user-friendly Archer-Analysis pipeline is a robust and specific technology to detect tumor genetic mutations for precision medicine of lung cancer patients.

Characteristics of SARS-CoV-2 Omicron BA.5 variants in Shanghai after ending the zero-COVID policy in December 2022: a clinical and genomic analysis.

An unprecedented surge of Omicron infections appeared nationwide in China in December 2022 after the adjustment of the COVID-19 response policy. Here, we report the clinical and genomic characteristics of SARS-CoV-2 infections among children in Shanghai during this outbreak. A total of 64 children with symptomatic COVID-19 were enrolled. SARS-CoV-2 whole genome sequences were obtained using next-generation sequencing (NGS) technology. Patient demographics and clinical characteristics were compared between variants. Phylogenetic tree, mutation spectrum, and the impact of unique mutations on SARS-CoV-2 proteins were analysed in silico. The genomic monitoring revealed that the emerging BA.5.2.48 and BF.7.14 were the dominant variants. The BA.5.2.48 infections were more frequently observed to experience vomiting/diarrhea and less frequently present cough compared to the BF.7.14 infections among patients without comorbidities in the study. The high-frequency unique non-synonymous mutations were present in BA.5.2.48 (N:Q241K) and BF.7.14 (nsp2:V94L, nsp12:L247F, S:C1243F, ORF7a:H47Y) with respect to their parental lineages. Of these mutations, S:C1243F, nsp12:L247F, and ORF7a:H47Y protein were predicted to have a deleterious effect on the protein function. Besides, nsp2:V94L and nsp12:L247F were predicted to destabilize the proteins. Further in vitro to in vivo studies are needed to verify the role of these specific mutations in viral fitness. In addition, continuous genomic monitoring and clinical manifestation assessments of the emerging variants will still be crucial for the effective responses to the ongoing COVID-19 pandemic.

An exploratory in silico analysis of bacteriocin gene clusters in the urobiome

Background: The role of the urobiome in health and disease remains an understudied area compared to the rest of the human microbiome. Enhanced culturing techniques and next-generation sequencing technologies have identified the urobiome as an untapped source of potentially novel antimicrobials. The aim of this study was to screen the urobiome for genes encoding bacteriocin production. Methods: The genomes of 181 bacterial urobiome isolates were screened in silico for the presence of bacteriocin gene clusters using the bacteriocin mining tool BAGEL4 and secondary metabolite screening tool antiSMASH7. Results: From these isolates, an initial 263 areas of interest were identified, manually annotated, and evaluated for potential bacteriocin gene clusters. This resulted in 32 isolates containing 80 potential bacteriocin gene clusters, of which 72% were identified as class II, 13.75% as class III, 8.75% as class I, and 5% as unclassified bacteriocins. Conclusion: Overall, 53 novel variants were discovered, including nisin, gassericin, ubericin, and colicins.

Characterization of BCP/PreC/C region quasispecies in treatment-naive patients with different phases of HBV infection using next-generation sequencing

BackgroundTo analysis of quasispecies (QS) changes and high-frequency mutations in the BCP/PreC/C region of patients at different phases of hepatitis B virus (HBV) infection and provides novel biomarkers for the diagnosis of chronic hepatitis B (CHB) patients. MethodsWith the application of next-generation sequencing technology, we were able to sequence the HBV BCP/PreC/C regions in 40 patients, each at different phases of the HBV infection. The heterogeneity of QS and the frequency of mutations were calculated using MEGA 7 software. ResultsOur results show that the complexity and diversity of the BCP/PreC/C QS in HBeAg-positive CHB patients are significantly higher than those in HBeAg-positive chronic infection patients, while HBeAg-negative chronic infection patients had significantly higher QS complexity and diversity than HBeAg-negative CHB patients. In addition, HBeAg-negative patients showed reduced complexity but increased diversity compared with HBeAg-positive patients. Receiver operating characteristic curves showed that G1764A, C2102T, dN and complexity of QS could be used as potential biomarkers for diagnosing HBeAg-positive CHB, while the A2189C, dS and complexity of QS could be used as potential biomarkers for diagnosing HBeAg-negative chronic hepatitis. Finally, our study also found that G1896A and A2159G may be hotspot mutations affecting HBeAg seroconversion. ConclusionOur research elucidates the evolution of HBV by analyzing QS heterogeneity and mutation patterns, offering novel serum biomarkers for enhancing clinical diagnosis and disease prognosis. This comprehensive approach sheds light on the intricate dynamics of HBV progression and paves the way for more precise medical interventions.

Differences in soil fungal communities under salinity gradients in arid and semiarid regions

Salinization is considered a significant threat to soil ecosystem and plant growth in arid and semiarid regions. Soil microorganisms are supposed to be essential in relieving soil salinization and enhancing plant salt tolerance. However, although the responses of soil fungal diversity and community structure to salt stress have been investigated, major knowledge gaps remain in the interactions and community assembly of abundant and rare fungal taxa, and fungal functional characteristics under different salt intensities. Here, next-generation sequencing technology were used to investigate the response of all, abundant and rare fungal taxa to salt stress in arid and semiarid regions. The results demonstrated that high salt stress reduced the complexity and stability of fungal networks and increased fungal collaborations. Rare taxa held a key position in the co-occurrence network and exhibited greater proficiency in collaborating with intermediate and rare taxa, thereby augmenting the resistance of the community and maintaining its stability. Notably, with increasing salt stress, the importance of rare taxa gradually enhanced, while the importance of abundant taxa decreased. Moreover, fungal communities were manipulated by stochastic processes under salt stress, while were also influenced by deterministic processes (heterogeneous selection), especially for rare taxa. Furthermore, low salinity conditions promoted the colonization of saprophytic and symbiotic fungi and inhibited the growth of pathogenic fungi. Functional groups associated with fungal parasite-soil saprotroph-undefined saprotroph function were extremely sensitive to soil salinity and exerted a pivotal influence in sustaining community stability. Our findings may broaden our understanding of how abundant and rare fungi react to salt stress, making it easier to forecast the possible loss of biodiversity due to soil salinization, and offering microbial references for the development of saline-alkaline soil.

Abstract 4885: Integrating mutational profiles and transcriptional data with ASTUTE to elucidate the key molecular functions involved in the pathogenesis of cancer

Abstract Cancer is a highly heterogeneous disease characterized by genomic and phenotypic changes that differ among tumor subtypes. A comprehensive understanding of the molecular heterogeneity is crucial for identifying molecular biomarkers and developing targeted therapies. While recent years have seen significant progress in genomic studies and advancements in next-generation sequencing technologies, elucidate the impact of individual genomic alterations on the transcriptome landscape of cancer cells remains essential. This knowledge is crucial for developing personalized therapies. To integrate mutational profiles and transcriptional data, we have developed a novel computational framework named ASTUTE (Association of SomaTic mUtaTions to Expression). ASTUTE establishes associations between somatic mutations and gene expression profiles, quantifying the results as fold changes and comparing the effects of individual mutations. In particular, ASTUTE leverages LASSO regularized regression for feature selection, identifying the most relevant mutated genes that exhibit a strong association with expression levels. Our goal is to create a valuable resource for identifying diagnostic markers and advancing the development of targeted therapies in cancer. To this end, we applied ASTUTE to two published bulk RNA-seq datasets of adult acute myeloid leukemia (AML) patients from the Beat AML program and the TCGA study to verify the capacity of our approach to identify genes whose expression correlates with the presence of specific somatic mutations. The first dataset comprises 585 samples, while the second one includes 173 specimens, both of them contain mutations and RNA-seq data. We executed ASTUTE on the two datasets independently, considering all genes for RNA-seq data and the alterations in the top 10 most mutated genes. We considered the associations consistently discovered in both cohorts. Our analysis revealed a strong association between NPM1 mutations and the expression of HOX genes. Specifically, HOXB6, HOXB5, HOXB3, HOXA5, HOXB2, and HOXA10 exhibited a log2 fold change higher than 1.5. The upregulation of these genes has been reported in association with NPM1 mutations in AML adult patients. Additionally, ASTUTE identified HOXA6, HOXA7, HOXA4, and HOXA9, whose expression has been described to be upregulated in the presence of NPM1 mutations in AML pediatric samples. Finally, we identified a robust relationship between NPM1 mutations and the expression of PBX3, MEIS, and ITM2A. The first two genes are upregulated in the presence of NPM1 mutations, while the third one is downregulated. Our analysis showcases ASTUTE's capability to identify potential markers and underscores the possibility to apply ASTUTE to different tumors datasets, with the aim to better characterize cancer heterogeneity and develop targeted therapies. Citation Format: Valentina Crippa, Diletta Fontana, Ivan Civettini, Luca Mologni, Rocco Piazza, Carlo Gambacorti-Passerini, Daniele Ramazzotti. Integrating mutational profiles and transcriptional data with ASTUTE to elucidate the key molecular functions involved in the pathogenesis of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4885.

Abstract 4881: Detecting cancer microbiota using unmapped RNA reads on spatial transcriptomics

Abstract Background: Recently, the study of microbiota has emerged as a novel area in cancer research. While next-generation sequencing (NGS) technologies are becoming more prevalent in the area, the acquisition of spatial information in microbiota is still challenging. Despite the possibility of detecting microbial RNAs on Visium (10X genomic, USA), methods depending on predefined host and microbial references cannot reliably capture microbial RNA reads, since Visium inherently lacks the ability to capture RNAs that are missing poly-A tails. Therefore, a reference-independent microbial RNA detection method needs to be developed for more trustworthy research on cancer microbiota on Visium. Methods: Initially, we reconstructed Visium data from a public raw dataset (Project: PRJNA811533, European Nucleotide Archive) derived from colorectal cancer (CRC) and oral squamous cell carcinoma (OSCC). BAM files were obtained by running Space Ranger on a human reference, GRCh38. These BAM files were firstly separated according to spatial barcodes with samtools and xargs. Then, microbial scores for each barcode were obtained using PathSeq. On the other hand, barcode-wise unmapped reads were extracted from the original BAM files simply by remaining unmapped reads, sorting them by spatial barcodes, and counting the number of reads. Then, the unmapped reads originating from host RNA reads were eliminated by regression analysis, remaining the microbial RNA reads. Subsequently, we conducted a comparison of microbial RNA reads from two different techniques. Results: By filtering out the unmapped reads associated with the host, microbial reads could be isolated. While these remaining microbial RNA reads show a significant correlation with the PathSeq scores, the unmapped reads were significantly higher than the PathSeq scores, increasing the statistical power for the downstream analysis with unmapped reads. Additionally, tissue regions with low PathSeq scores and high volumes of non-human unmapped reads were identified. These regions may indicate the presence of microbial sequences or RNA species that were not detected in the PathSeq analysis. Conclusion: The use of unmapped reads enables us to capture a greater number of RNA transcripts compared to PathSeq to indirectly analyze cancer microbiota. This means that we can observe hard-to-identify RNA variants, such as unstable RNAs or new species originating from the interaction between microbial RNAs and host RNAs. Our methods can provide plausible explanations for the existence of microbial RNAs on Visium, and we suggest a reference-independent detection of cancer microbota reads by utilizing unmapped reads. Citation Format: Jeongbin Park, Seo Hye Park, Dongjoo Lee, Jae Eun Lee, Daeseung Lee, Kwon Joong Na, Hongyoon Choi, Hyung-Jun Im. Detecting cancer microbiota using unmapped RNA reads on spatial transcriptomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4881.

Abstract 2337: Accelerated optical genome mapping analysis with Stratys Compute and Guided Assembly

Abstract Background Optical genome maps (OGM) from Bionano enable the detection of genomic structural and copy number variants that cannot be detected by next-generation sequencing (NGS) technologies and are often missed by conventional cytogenetic techniques. Bionano has developed bioinformatics pipelines for calling structural and copy number variants including the Bionano Solve de novo assembly pipeline for constitutional analysis and the Rare Variant Analysis (RVA) pipeline for low-allele-fraction cancer applications. Both pipelines are computationally intensive and currently take 5-10 hours on the latest generation of the Bionano Saphyr® Compute which is deployed as a four-node compute cluster and requires significant IT resources. Methods To increase throughput and simplify the deployment of the compute resources needed to support the Stratys™ optical genome mapping instrument, Bionano has developed Stratys™ Compute. Stratys Compute improves both compute and analytical performance by adapting compute-intensive stages in the Solve pipeline to run on GPUs and by developing the Guided Assembly pipeline. Stratys Compute is powered by state-of-the-art NVIDIA RTX 6000 Ada generation cards and CUDA-optimized refinement, alignment, and structural variation detection kernels to accelerate OGM analysis. Stratys Compute is a standalone workstation placed adjacent to Stratys instrument. This will minimize the IT footprint and bypass the integration with the customer site’s data center. We have incorporated these optimizations into the new Guided Assembly pipeline, which aims to combine the low-allele fraction detection capability of the RVA pipeline with the whole genome coverage and ability to detect smaller structural variants enabled by the de novo assembly pipeline. The Guided Assembly pipeline uses the reference genome as an initial seed followed by extension, refinement, and structural variant calling. This new analysis method has been evaluated through comparison to previous results from both existing pipelines and standard benchmarking datasets used to estimate structural variant calling performance and is deployed on Stratys Compute for both constitutional and low allele-fraction applications. Results Guided Assembly has been adapted to run on GPU hardware in a simplified compute tower that can be deployed to a lab along with the Stratys instrument without the need for a dedicated server room. We found concordance between the guided assembly results and our previous de novo and RVA pipeline results. We also found increased sensitivity at low allele fractions for detecting insertion variants smaller than 5 kb and larger than 200 kb while finding equivalent performance for other variant types with the updated methods. The accelerated Guided Assembly for constitutional and low-allele-fraction applications will be available to early access customers in Q4 2023 with full commercial release in Q2 2024. Citation Format: Damla Senol Cali, Thomas Anantharaman, Martin Muggli, Samer Al-Saffar, Charles Schoonover, Neil Miller. Accelerated optical genome mapping analysis with Stratys Compute and Guided Assembly [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2337.

Abstract 2266: Detection of androgen receptor splice variants from clinical sequencing

Abstract Background: Androgen receptor splice variant-7 (AR-v7) has been widely studied as a biomarker of resistance to AR-targeted therapy in castration-resistant prostate cancer (CRPC). Various methods have been used to detect AR-v7 in CRPC specimens, including next generation sequencing (NGS) technology. However, NGS technologies applied in clinical sequencing have focused on using blood or fresh-frozen CRPC tissue specimens. There is not yet an AR-v7 detection system tailored to formalin-fixed paraffin-embedded (FFPE) tissue specimens commonly used for clinical sequencing in hospitals. Methods: In this respect, we propose a novel approach to identify AR-v7 in targeted RNA sequencing (RNA-seq) data derived from FFPE specimens. This approach can identify, in addition to AR-v7, all constitutively active AR splice variants (AR-Vs) that are co-expressed with AR-v7. In short, our two-step approach first gathers soft-clipped or divided reads that are adjacent to the splicing sites of AR-Vs and then yields the number of splitting reads that support the existence of AR-Vs. Next, the algorithm selects the paired-end reads whose one side and the other side are mapped to the preceding and following exons, respectively. The final number of spanning reads are calculated following to the removal of low-quality reads. Results: We validated the proposed approach using two large-scale, independent RNA-seq datasets of prostate cancer (PC) samples: 111 samples from Seoul National University Hospital (SNUH) and 558 samples from The Cancer Genome Atlas (TCGA) dataset. The majority of both datasets were localized PC tumors, especially in the SNUH dataset, where localized PC accounted for 91% of the total. Overall, our approach successfully identified samples with putative AR-Vs, including AR-v7, AR-v3, and AR-v9. Statistical analyses of 111 SNUH PC patients suggested potential detection threshold in clinical sequencing settings (at least 200 split reads). In the SNUH dataset, the AR-v7 positive group, which included 5 patients (5%) with values above the threshold, shared the following characteristics: higher AR-v7/full length AR expression levels, AR amplification and co-expression with AR-v3/AR-v9. AR-v7 positivity was experimentally validated by Sanger sequencing. The similar pattern was also found in the analysis of TCGA dataset. Conclusions: These results demonstrate that the detection system can successfully identify AR-v7 positivity not only for metastatic PC but also for patients with localized PC through clinical sequencing. We expect that the further in-depth analyses including larger samples and clinical outcomes can discover clinical applicability of AR-v7. Citation Format: Suhyun Hwangbo, Sungyoung Lee, Sheehyun Kim, Hongseok Yun. Detection of androgen receptor splice variants from clinical sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2266.

Abstract 3671: Analytical performance of the Oncomine™ Dx Express Test, a CE-IVD NGS liquid biopsy assay for identification of clinically relevant variants

Abstract For in vitro Diagnostic use only. Not available in all regions including the United States. Introduction Minimally invasive blood-based liquid biopsy using cell-free total nucleic acid (cfTNA) and next generation sequencing (NGS) has substantially evolved in the field of clinical diagnostics for oncology, for detection of molecular therapeutic targets in non-small cell lung cancer (NSCLC). Here we describe analytical validation results for cfTNA using the CE-IVD Oncomine™ Dx Express Test (ODxET) assay, a qualitative in vitro diagnostic test that uses targeted NGS technology, the Ion Torrent Genexus™ Dx Integrated Sequencer to detect SNV, indel and copy number gain present in 42 genes and fusions in 7 genes from cfTNA isolated from NSCLC plasma samples. Methods Plasma samples from NSCLC patients were screened for variants of interest on several important gene loci. Screening involved isolation of cfTNA from K2-EDTA-derived plasma using the Genexus™ Cell-Free Total Nucleic Acid Purification kit on an automated purification system and sequencing was performed on the Genexus™ Dx integrated sequencer using the ODxET assay. Plasma samples having clinically relevant variants from the set of screened plasma samples were used to perform the validation studies. Results Analytical sensitivity and specificity of NSCLC plasma samples were characterized through determination of limit of detection (LOD) and limit of blank (LOB), respectively. The LOD level tested for DNA SNVs, and indels at 5 ng (minimum) input level ranged from 0.62% to 1.82% allelic frequency (AF), while 30 ng (maximum) input shows the LOD level ranging from 0.23% to 0.42% AF. The LOD for the tested RNA fusions ranged from 4.2 to 19.6 molecular counts for 5ng input and 4.9 to 8.0 molecular counts for 30ng input. Furthermore, LOB for the ODxET assay was determined by testing wild type (WT) cfTNA extracted from 30 healthy donor blood plasma samples, which were confirmed to be negative at all variant locations. The analytical accuracy study shows the false positive rate at 0.20% for SNVs, 0% for indel locations and fusion targets. In addition, the analytical reproducibility study shows 99.64% intra-run repeatability call rate for DNA variants and 98.75% for RNA variants. Conclusion In conclusion, we establish that the ODxET assay on Ion Torrent Genexus Dx Integrated Sequencer, is fast and efficient while demonstrating high sensitivity, specificity, and reproducibility for testing NSCLC liquid biopsy samples. Citation Format: Madhuri Jasti, Swasti Raut, Diarra Hassell, Nader Ezzedine, Daniela Garcia, Stephen Wunsch, Nick Siepert, Elliott Martinez, Emilia Ostrowska, Jeff Schagemann, Jian Gu, Thilanka Jayaweera, Luming He, Angie Cheng. Analytical performance of the Oncomine™ Dx Express Test, a CE-IVD NGS liquid biopsy assay for identification of clinically relevant variants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3671.