DNA Panel Research Articles

Development, Optimisation and Validation of a Novel Multiplex Real-Time PCR Method for the Simultaneous Detection of Cryptosporidium spp., Giardia duodenalis and Dientamoeba fragilis.

The enteric protozoan parasites Cryptosporidium spp., Giardia duodenalis and Dientamoeba fragilis are-to various extents-contributors to the burden of gastrointestinal illness in high-income countries. Detection of these pathogens by microscopy examination is challenging because of the limited sensitivity and need for specific staining procedures. We developed and optimised a new multiplex real-time PCR assay for the simultaneous detection of Cryptosporidium spp., G. duodenalis and D. fragilis in clinical (stool) samples. The diagnostic performance of the assay was evaluated against a large panel of well-characterised DNA samples positive for Cryptosporidium spp. (n = 126), G. duodenalis (n = 132) and D. fragilis (n = 49). The specificity of the test was assessed against a DNA panel from other intestinal or phylogenetically related parasites (n = 105) and faecal DNA from individuals without clinical manifestations (n = 12). The assay exhibited a diagnostic sensitivity of 0.90-0.97 and a diagnostic specificity of 1. The limit of detection was estimated for Cryptosporidium (1 oocyst) and G. duodenalis (5 × 10-4 cysts). The method allowed the detection of four Cryptosporidium species (C. hominis, C. parvum, C. meleagridis and C. cuniculus) and five G. duodenalis assemblages (A-E) without cross-reacting with other parasites belonging to the phyla Amoebozoa, Apicomplexa, Euglenozoa, Microsporidia, Nematoda and Platyhelminthes. This newly developed multiplex real-time PCR assay represents a novel alternative for the rapid and accurate detection of Cryptosporidium, G. duodenalis and D. fragilis in clinical settings.

Utility of a targeted next-generation sequencing-based genetic screening panel in patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome.

This study aims to investigate a genetic panel in patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome and examine its performance for an accurate differential diagnosis. Between January 2021 and January 2022, a total of 104 children with PFAPA syndrome (63 males, 41 females; mean age: 4.8±2.3 years; range, 1.2 to 8.9 years) were retrospectively analyzed. Next-generation sequencing test was performed using a custom QIAGEN- QIAseq™ Targeted DNA Panel which includes six genes namely ELANE, LPIN2, MEFV, MVK, NLRP3, and TNFRSF1A. Of 104 patients, 38 (36.5%) had variants in the genetic panel. The most common variants were found in the MEFV gene (n=35, 33.6%), the most frequent genotype was E148Q heterozygosity (n=16). Four and two patients were eventually diagnosed with Familial Mediterranean fever (FMF) and hyperimmunoglobulin D syndrome (HIDS), since they had confirmative biallelic pathogenic in the MEFV and MVK genes, respectively. A genetic panel, including MEFV and MVK genes, may be useful in patients, clinically resembling PFAPA, since they may have HIDS or FMF, but lack typical features of the exact disease. Nonetheless, we believe that distinct genetic panels should be developed for different populations.

Analytical and clinical validation of a custom 15-gene next-generation sequencing panel for the evaluation of circulating tumor DNA mutations in patients with advanced non-small-cell lung cancer.

BackgroundThis is a pilot proof-of-concept study to evaluate the utility of a custom 15-gene circulating tumor DNA (ctDNA) panel as a potential companion molecular next-generation sequencing (NGS) assay for identifying somatic single nucleotide variants and indels in non-small-cell lung cancer (NSCLC) patients. The custom panel covers the hotspot mutations in EGFR, KRAS, NRAS, BRAF, PIK3CA, ERBB2, MET, KIT, PDGFRA, ALK, ROS1, RET, NTRK1, NTRK2 and NTRK3 genes which serve as biomarkers for guiding treatment decisions in NSCLC patients.MethodThe custom 15-gene ctDNA NGS panel was designed using ArcherDX Assay Designer. A total of 20 ng or 50 ng input ctDNA was used to construct the libraries. The analytical performance was evaluated using reference standards at different allellic frequencies (0.1%, 1%, 5% and parental). The clinical performance was evaluated using plasma samples collected from 10 treatment naïve advanced stage III or IV NSCLC patients who were tested for tissue EGFR mutations. The bioinformatics analysis was performed using the proprietary Archer Analysis Software.ResultsFor the analytical validation, we achieved 100% sensitivity and specificity for the detection of known mutations in the reference standards. The limit of detection was 1% allelic frequency. Clinical validation showed that the clinical sensitivity and specificity of the assay for detecting EGFR mutation were 83.3% and 100% respectively. In addition, the NGS panel also detected other mutations of uncertain significance in 6 out of 10 patients.ConclusionThis preliminary analysis showed that the custom 15-gene ctDNA NGS panel demonstrated good analytical and clinical performances for the EGFR mutation. Further studies incorporating the validation of other candidate gene mutations are warranted.

ANALYTICAL PERFORMANCE OF A DNA/RNA-BASED NEXT-GENERATION SEQUENCING (NGS) PANEL FOR MYELOID NEOPLASMS

Myeloid neoplasms (MNs) are a heterogeneous group of neoplasms including acute myeloid leukemia, myelodysplastic syndrome, myeloproliferative neoplasms and myelodysplastic syndrome/myeloproliferative neoplasms. MNs show a complex genetic basis, and the number of alterations to be analyzed for risk diagnostic, stratification and management of patients increases continuously. Consequently, there is a demand for multiple molecular and cytogenetic techniques with the aim of detecting a wide variety of genetic abnormalities. Since conventional techniques are insufficient to study all such abnormalities, the NGS panel has become a useful tool for broad characterization of the spectrum of mutations in MNs. However, before NGS panels can be introduced in the laboratory routine, their performance should be evaluated. In this context, we describe the analytical performance of the Oncomine™Myeloid Research Assay (OMA) (Thermo Fisher), a DNA/RNA-based amplicon sequencing panel, that evaluated simultaneously 40 genes (17 full genes and 23 hotspots genes) and 29 fusions drivers genes (over 600 partners) known to be recurrently mutated in MNs. Commercial controls Seraseq Myeloid Mutation DNA and the Seraseq Myeloid Fusion RNA were used for sensitivity, specificity, accuracy, repeatability, reproducibility and limit of detection (LoD) testing. Prospective sequencing was performed for samples from 34 patients presenting with suspected or confirmed MN. Libraries was prepared by manual method and sequenced by the Ion S5 Sequencer. Data obtained were analysed on Ion Reporter 5.18 software. The OMA assay showed good performance in terms of depth of coverage, on-target reads, and uniformity. The mean reads lenght ranged from 223 to 231 bp for DNA sample and from 88 to 124 bp for RNA, within the expected standard for the panel. The panel achieved 98,8% and 100% concordance with DNA and RNA controls, reaching analytical sensitivity of 99% and 100% for DNA and RNA, respectively. Regarding the type of DNA mutation: single nucleotide variants (SNP), indels or indels hot spots, the sensitivity found was 100%, 96% and 95%, respectively. The accuracy and analytical specificity was 100% for DNA panel. The LoD was 5% variant allele fraction (VAF) for DNA (SNP and indel) and 1-log reduction from initial number of reads counts for RNA fusion genes. Repeatability and reproducibility were 98% for DNA and 100% for RNA. However, the coefficient of variation (CV) within-run and between-run in VAF was >20% for large indels in CALR, FLT3 (ITD) and SRSF2 . The vertical coverage of each sample was inspected with a coverage threshold of 100X. Some amplicons in the assay failed repeatedly (ASXL1_1.875, BCOR_8.202477, BRAF_18.30633, CEBPA_1.1.86676, PRPF8_12.173121, SH2B3_1.85663). However, the OMA is unable to detect specific variants in ASXL1 (c.1900_1922del23 and c.1934_1935insG) and CEBPA (c.68_69insC). This is a known limitation of the Ion Torrent chemistry for accurate sequencing of large homopolymers and high GC content regions. Of the 34 patient samples, 28 (87.5%) had at least one reportable variant. A total of 58 DNA variants and six gene fusions were detected. Some variants were confirmed by orthogonal techniques. In conclusion, OMA is a highly accurate and reproducible NGS panel for the detection of common genetic abnormalities in MNs.

S410 Algorithm Training and Independent Test Set Performance for a Molecular Non-Endoscopic Test for Detection of Esophageal Adenocarcinoma and Barrett’s Esophagus in Multicenter Cohorts

Introduction: Sedated endoscopy for Barrett’s esophagus (BE) and esophageal adenocarcinoma (EAC) detection is invasive and expensive. Non-endoscopic BE/EAC detection tools have been guideline-endorsed to facilitate higher patient participation at lower cost. We previously described a promising panel of 5 methylated DNA markers (MDMs) assayed on esophageal specimens obtained by a sponge-on-a-string (SOS) cell collection device in phase II studies. We aimed to train an algorithm (establishing marker cut offs, to adjudicate samples as positive/negative) using a final MDM panel followed by testing in an independent sample set. Methods: Algorithm training samples (N=352) were prospectively collected from patients seen at 6 US medical centers. Test samples (N=125) were obtained from an independent, NIH-funded study conducted at 3 US medical centers. Cases had columnar metaplasia with intestinal metaplasia; controls had no endoscopic evidence of BE. Histology was reviewed by expert GI pathologists. The SOS device (25 mm, 10 ppi) was swallowed and withdrawn after 6-8 minutes followed by criterion standard endoscopy within 24 hours. DNA was extracted and bisulfite treated. Five MDMs were blindly assayed using the long probe quantitative amplified signal method. The algorithm was set using cross-validated logistic regression. The locked algorithm was applied to assay results from the test set. Results: Baseline characteristics of patients in training and test sets were comparable (Table). The final panel included 3 MDMs (NDRG4, VAV3, and ZNF682) and a reference marker (B3GALT6). Overall sensitivity for BE/EAC detection in the training set was 81% (95% CI 76-88%) at 90% (85-94%) specificity. Overall BE/EAC sensitivity in the test set was 88% (78-94%) at 84% (70-93%) specificity. Sensitivity for HGD and EAC was 100% in the training and test sets. Sensitivity for short segment NDBE in the test set was 63% (38-84%). Areas under the receiver operating characteristic (AUROC) curve for BE/EAC detection were 0.92 (95% CI 0.89-0.95) and 0.94 (0.90-0.98) in the training and test sets, respectively (Figure). The algorithm was not influenced by age, sex, or smoking history. 97% of participants in the training set and 85% in the test set successfully swallowed the SOS device, which was well tolerated and safe. Conclusion: A 3-MDM panel for BE/EAC detection demonstrated excellent sensitivity for high risk BE cases in multi-center case control training and test sets.Figure 1.: Area under the receiver operating characteristics curves for a 3-marker methylated DNA panel assayed from cytology specimen extracted DNA in training and test sets. Table 1. - Baseline characteristics of patients and performance characteristics of SOS test (overall sensitivity and specificity, and stratified by BE dysplasia grade) in training and test sets Variable Training Set (N=198 controls,154 cases) Test Set(N= 44 controls,81 cases) P value (comparing training and test sets) Control Case Control Case Mean (SD) age 55 (13) 65 (10) 52 (15) 65 (11) 0.312 Male Sex (%) 102 (52) 119 (77) 17 (39) 64 (79) 0.992 Mean (SD) BMI 29 (7) 30 (6) 30 (7) 30 (6) 0.283 Ever Smokers % 77 (39) 87 (56) 18 (41) 47 (58) 0.733 Mean *SD) BE length, cm - 4 (3) - 5 (3) 0.070 Long segment BE, N, (%) - 97 (63) - 56 (69) 0.426 Short segment BE, N (%) - 57 (37) - 25 (31) BE dysplasia grade, N (%) EAC - 12 (8) - 2 (2) HGD - 18 (12) - 11 (14) LGD - 7 (4) - 10 (12) IND - 18 (12) - 14 (17) NDBE (long segment) - 57 (37) - 25 (31) NDBE (short segment) - 42 (27) - 19 (24) Training Set% Positive (95% CI) Test Set% Positive (95% CI) Overall 81% (76-88%) 88 (78-94) Dysplasia grade EAC 100 (100-100) 100 (16-100) HGD 100 (100-100) 100 (72-100) LGD 71 (0-100) 90 (55-100) IND 74 (0-100) 93 (66-100%) NDBE (long segment) 91 (73-100) 96 (80-100%) NDBE (short segment) 61 (25-100) 63 (38-84%) Control (No BE) 10 (2-21) 16 (7-30)

ALL-268 Genetic Classification of B-Cell Precursor Adult Acute Lymphoblastic Leukemia Patients Enrolled in LAL19 Trial from the Pethema Group: Response to Treatment and Survival

B-cell precursor acute lymphoblastic leukemia (BCP ALL) is a genetically heterogeneous neoplasm with >20 biologic subtypes. Each subtype shows specific genetic traits that determine relapse risk and patients' survival. To establish the genetic subtype (primary alteration) of adult BCP ALL patients enrolled in the PETHEMA LAL19 trial (NCT04179929) and to correlate them with measurable residual disease (MRD) level and survival. In the LAL19 trial (NCT04179929), Ph-negative patients (18-65 y) with MRD≥0.01% at day+35 or high-risk genetics receive alloHSCT and MRD<0.01% patients with standard-risk genetics receive maintenance chemotherapy. The genetic analyses are centralized: FISH and NGS DNA panel (Hospital de Salamanca), RNAseq panel (Hospital 12 de Octubre), FISH panel (Hospital La Fe), and SNP array (Josep Carreras Institute/ICO-Hospital Germans Trias i Pujol). MRD determinations are centrally done by next-generation flow cytometry in the Cytometry Service, NUCLEUS, University of Salamanca. The genetic subtype was identified in 54% (82/152) of patients. The most recurrent subtypes were KMT2Ar (11%), Ph-like (mostly CRLF2::IGH, 11%), low-hypodiploid (7%), PAX5 P80R (7%), high-hyperdiploid (6%), and t(1;19)/TCF3::PBX1 (6%). In addition, t(12;21)/ETV6::RUNX1, ZNF384r, and iAMP21 subtypes (1.5% each) and MEF2Dr, MYCr, IDH1 R132 subtypes (<1% each) were found. Regarding secondary alterations, NRAS (15%), TP53 (13%), PAX5 (13%), and KRAS (10%) mutations were the most frequently observed. Twelve patients were refractory (mainly low-hypodiploid, Ph-like, MYCr, and B-other/unclassified patients). Statistically significant differences were observed for day+35 MRD levels between genetic subtypes. Ph-like, low-hypodiploid, and KMT2Ar showed lower frequencies of MRD<0.01% (17%, 33%, and 57%, respectively) than patients with PAX5P80R (100%), t(1;19)/TCF3::PBX1 (83%), and high-hyperdiploid (75%) (P=0.006). Despite the short median follow-up (11 months), differences in response to treatment were reflected in patients' survival. Significant differences in survival were observed between poor-response subtypes (Ph-like, KMT2Ar, and low-hypodiploid) and good-response subtypes (PAX5 P80R, t(1;19)/TCF3::PBX1, and high-hyperdiploid). Knowing the genetic subtype of each ALL is crucial to better predict relapse risk and offer the best (personalized) treatment for each patient.

Hepatocellular carcinoma surveillance in patients with non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) may progress to cirrhotic or non-cirrhotic hepatocellular carcinoma (HCC), and is currently recognized as the fastest growing cause of HCC worldwide. Accordingly, professional society guidelines recommend HCC surveillance in patients with cirrhosis from any etiology, and some may consider it beneficial in subgroups with non-cirrhotic NAFLD at higher risk for HCC. Notably, patients with NAFLD-related HCC are more likely to have HCC diagnosed at more advanced stages and have poorer outcomes when compared to other etiologies, and suboptimal effectiveness of HCC surveillance programs is a major culprit. In this review, we summarize the current guidelines for HCC surveillance and discuss its benefits versus potential harms for NAFLD patients. We also address the unique challenges of HCC surveillance in NAFLD, including higher proportion of NAFLD-related HCC without cirrhosis, poor recognition of at-risk patients, lack of consensus regarding the value of surveillance in non-cirrhotic NAFLD, subpar effectiveness of surveillance tools related to NAFLD phenotype, and preponderant surveillance underuse among NAFLD patients. Finally, we examine the effectiveness of currently used surveillance tools (i.e., ultrasound and alpha fetoprotein) and outline future perspectives including emerging risk stratification tools, imaging surveillance strategies (e.g., abbreviated magnetic resonance imaging protocols), blood-based biomarkers (e.g., GALAD and circulating tumor DNA panels), and interventions to improve surveillance adherence.

Feline Fertility: Consequences of inbreeding and implications for reproductive fitness.

When compared with the number of individuals that make up a dog breed, the population within a given cat breed is very small. Therefore, to maintain a breed standard, a certain degree of inbreeding is necessary. However, when inbreeding reaches a certain threshold, it can lead to decreased fertility, which manifests as failure to conceive, smaller litter size, increased neonatal illness and neonatal mortality. Breeders should be encouraged to keep comprehensive records on breeding outcomes, including number of kittens born, neonatal vitality, daily kitten weights and kitten health at weaning. Commercially available DNA panels are available to inform and facilitate excellent breeding choices and can estimate the coefficient of inbreeding. Clinicians should include a review of the degree of inbreeding in the work-up for any cattery or cat colony experiencing decreased fertility. The objective of this article is to provide clinicians, especially those working with cat breeders, with an easy-to-understand guide to genetics and to demonstrate how inbreeding influences fertility and neonatal survival. Medical records and the pedigree of the cats in question are required to investigate cases of infertility that may be related to inbreeding. A DNA analysis kit that measures genetic diversity and health parameters can also be helpful; those that have been developed by geneticists and veterinarians at universities are preferable, as they include access to highly skilled genetic counselors and researchers who are open to working up newly discovered genetic diseases. The material provided is based on current literature and the author's own studies examining outcomes in a closed cattery.

Abstract 631: Validation of a panel of methylated DNA and protein markers for multi-cancer detection in plasma

Abstract Purpose: Many cancer deaths could be avoided, and survival could be improved with detection of cancer at an earlier stage. Screening programs for breast, colon, and cervical cancer as well as the NLST trial for lung cancer screening demonstrated significant improvement in survival rates with screening. However, for 2021, the American Cancer Society estimates these screened cancers represent less than ~40% of cancer incidence and deaths. The remainder of cancer deaths occur because of tumors in unscreened organs and, therefore, a multicancer test that detects cancer in these organs can increase survival rates. By focusing on detection of unscreened cancers, this type of multicancer test would be complementary to current screening procedures. Here we describe the validation of a combined panel of methylated DNA markers (MDMs) and proteins for multicancer detection through testing an independent set of case/control samples. Experimental Procedures: In this study, we further evaluate the performance of our previously identified panel of 15 MDMs and 5 proteins for multicancer detection (Allawi et al., 2021 AACR Annual Meeting) by testing 315 controls and 160 cases encompassing 6 cancer types (liver, esophageal, lung, ovarian, pancreatic, and stomach). All samples used in the study were case-control collections with smoking status, age, and gender matching between cases and asymptomatic controls. Testing was performed in blinded fashion using multiplex PCR followed by LQAS (Long probe Quantitative Amplified Signal) assay on bisulfite converted DNA extracted from 3 mL of plasma collected in LB Gard® blood tubes. Protein concentrations were determined from paired serum aliquots and combined with MDMs for a multi-analyte analysis. The subjects were divided into training and validation with equal representation of cancer type, staging, gender, and age. Two thirds of the cases and controls were used to train with a logistic prediction algorithm, and the remaining 1/3 were used to validate the model. Results: Using stepwise logistic regression, a training model of MDMs and protein markers resulted in an area under the receiver operating characteristics curve (AUC) of 0.97 and cancer sensitivity of 89% at 98% specificity. The same model predicted the validation set with an AUC of 0.96 and cancer sensitivity of 85% at a specificity of 95%. Applying the algorithm to the combined training and validation sets resulted in sensitivities and specificities of 88% and 97%, respectively. The sensitivities per cancer type ranged from 73% for pancreatic cancer to 97% for lung cancer. Conclusion and Next Steps: This study demonstrates the performance of our MDMs and protein markers and their importance as components in our multi-omics strategy for multicancer detection. The next steps would be to expand the testing to include additional cancer types and combine with NGS-based methods to improve performance and optimize workflow. Citation Format: Hatim T. Allawi, Slava Katerov, Abram Vaccaro, Harrison L. Fleming, Debra E. Rugowski, Brittany Otto, Justin Heilberger, Jillian Cassel, Jacquelyn Hennek, William Taylor, Graham Lidgard. Validation of a panel of methylated DNA and protein markers for multi-cancer detection in plasma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 631.

Abstract 2941: SureSelect Cancer CGP assay for detection of the common mutation types found in cancer

Abstract Background: The current standard for genomic profiling of cancer tissues relies upon multiple technologies to aid in tumor characterization. Here we describe a comprehensive genomic profiling pan-cancer assay that detects single nucleotide polymorphisms and small insertions/deletions, somatic copy number alterations, translocations, RNA fusions and exon-skipping events, as well as determining Tumor Mutation Burden (TMB) score and Microsatellite Instability (MSI) using both Tumor-only and Tumor-Normal analysis methods. The assay consists of hybrid capture-based panels for enrichment of both gDNA and total RNA extracted from FFPE samples. DNA and RNA samples are processed using Agilent’s SureSelect XT HS2 chemistry, including full automation on the Magnis NGS prep system, and analyzed using the Alissa Reporter software, streamlining the workflow and analysis. Methods: Content of the assay was curated using literature review and input from multiple cancer databases. The assay employs a modular design with a DNA capture panel covering all actionable genes/variants as well as genes that are commonly mutated across cancer types, and an RNA panel covering fusion driver mutations. Probes were designed to cover the exons of all genes with enhanced coverage of clinically actionable mutations. Selected genes in the DNA panel have additional coverage allowing for copy number determination and detection of translocations in hot-spot regions. The data analysis pipeline in the Alissa Reporter software allows for the seamless analysis of the sequencing results and provides sensitive and accurate detection of the variants. The software also allows for visualization in the genomic context, QC metrics tracking, and results reporting functionalities, giving users a full picture of their samples. Results: Performance was demonstrated on &amp;gt;80 FFPE samples and reference standards with accuracy determined by concordance with gold-standard measurements. For TMB analysis, FFPE samples were analyzed using the SureSelect Cancer CGP assay and whole-exome sequencing. The values from both assays show high correlation (r &amp;gt; 0.8). Microsatellite instability measured by the assay was 93% concordant with MSI-PCR. ERBB2 copy number determination in breast cancer samples was 87% concordant with FISH, while translocation and RNA fusion detection were both &amp;gt;85% concordant to FISH for a set of ALK+ NSCLC samples. Conclusion: This work represents an important advancement in the development of an assay to detect the common mutation types found in cancer as well as provide information on the genomic biomarkers, TMB and MSI from a single FFPE sample. For Research use Only Citation Format: Akanksha Khare, Anne Bergstrom Lucas, Joachim de-Schrijver, Manjula Aliminati, Hanjun Shin, Linus Forsmark, Barbara Novak, Jeroen Crappe, Michael Ruvolo. SureSelect Cancer CGP assay for detection of the common mutation types found in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2941.

Abstract 5756: Next-generation sequencing (NGS) reveals different molecular profiles of pediatric sarcoma in children and adults

Abstract Background: Pediatric sarcomas represent approximately 12% of all pediatric cancers with over 100 subtypes. Although some molecular detection techniques can be used to assist the diagnosis and treatment of pediatric sarcoma, it still remains challenging due to overlapping morphological features and limited biopsy specimens. Here we performed next generation sequencing (NGS) to analyze the molecular profiles of pediatric and adult sarcomas in China. Methods: A total of 700 Chinese patients with sarcoma were collected. The tumor tissue and matching blood specimens were tested by the integrative DNA and RNA sequencing panel Onco Panscan plus࣪ at Genetronhealth. Results: Of the 700 sarcoma patients, there were 224 children (32%) and 476 adults (68%). Difference from the almost same ratio of men to women in adults, there were more males (n = 134) than females (n = 90) in children. Rhabdomyosarcoma was the most common soft tissue tumor in children, accounting for 24.1% (n = 54), followed by Ewing's sarcoma (9.8%, n = 22) and Osteosarcoma (8.5%, n = 34), while Angiosarcoma (3.8%, n = 18) and Fibrosarcoma (3.6%, n = 17) were the most common in adults. Based on mutation types, the frequent alterations were missense mutations (n = 326, 51.2%), fusions (n = 129, 20.3%) and copy number variants (n = 66, 10.4%) in children with a mean of 3 mutations per patient, and missense mutations (n = 1438, 66.8%), fusions (n = 221, 10.3%) and truncating mutations (n = 215, 10.0%) in adults with an average 5 mutations. TP53 (12.9%, n = 29), EWSR1 (8.9%, n = 20) and ALK mutations (6.7%, n = 15) were common in children, which was distinct from TP53 (29.4%, n = 140), NF1 (4.8%, n = 23), CTNNB1 (4.2%, n = 20) and RB1 (4.2%, n = 20) in adults. Based on NGS results, pathological subtypes could be confirmed in 40.2% (90/224) and 48.1% (229/476) of children and of adults sarcoma patients, respectively. In addition, we identified a total of 72 drug-targeted gene mutations in the 57 children patients, of which 35 (48.6%) gene mutations could be targeted by FDA-approved drugs. In adults, 256 drug-targeted gene mutations were detected and the proportion of actionable mutations was up to 78.9% (n = 202). Conclusion: The genomic landscape of pediatric sarcomas is different from that of adults. NGS aids in the subtype classification and clinical guidance of pediatric sarcomas, providing evidence for personalized treatments with clinical benefit. Citation Format: Weisong Cai, Fang Liu, Xuejiao Liu, Xiaojuan Wang, Chunyang Wang, Tonghui Ma, Shu Li. Next-generation sequencing (NGS) reveals different molecular profiles of pediatric sarcoma in children and adults [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5756.

Abstract 759: Analytical performance of a novel next generation sequencing assay for myeloid MRD

Abstract The detection of molecular measurable residual disease (MRD) for acute myeloid leukemia (AML) has shown promise as a prognostic for AML. To support clinical and translational research into potential strategies for MRD monitoring applications in the future, a next-generation sequencing (NGS) assay, the Oncomine Myeloid MRD Assay (RUO), was developed. This assay utilizes Unique Molecular Tags (UMT) and Ion AmpliSeq HD™ technology to detect ultra-low frequency genetic alterations from blood or bone marrow samples. The workflow includes manual AmpliSeq HD library construction, templating on Ion Chef™, and sequencing on Ion GeneStudio™ sequencers. The assay contains both DNA and RNA targeted panels to detect SNVs, indels, fusion markers, and microhaplotype. The DNA panel covers 1256 hotspots in 33 genes, including key mutations in NPM1, FLT3, DNMT3A and full gene coverage for CEBPA and TP53. The panel achieved a limit of detection (LOD) of 0.1% when tested on 27 reference genomic DNA samples and over 40 clinical research samples. The RNA panel detects 1003 fusion isoforms for 27 fusion driver genes, including BCR-ABL1, RUNX1, CBFB-MYH11, and KTM2A (MLL) partial tandem duplications (PTDs) and fusions. The assay also includes a Microhaplotyping panel to monitor chimerism. The workflow is analytically verified and includes an optimized analysis pipeline for sensitive and accurate MRD detection. Overall, this comprehensive Myeloid MRD (RUO) assay reliably identifies DNA mutations and fusions with high sensitivity and provides a new tool for myeloid MRD research. RUO: For Research Use Only. Not for use in diagnostic procedures. Citation Format: Hua Zhang, Xinzhan Peng, Guobin Luo, Annie Kraltcheva, David Mandelman, Michelle Swimley, Eli Pazol, Jose Espinoza, Scott Mitchell, Bo Ding, Ratnesh Singh, Doug Fenger, Na Li, Andrew Hatch, Vadim Mozhayskiy, Steven Roman, Sophie Rozenzhak. Analytical performance of a novel next generation sequencing assay for myeloid MRD [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 759.

EASplex: A panel of 308 AISNPs for East Asian ancestry inference using next generation sequencing

Ancestry inference is useful in many scientific fields, such as forensic genetics, medical genetics, and molecular archaeology. Various ancestry inferring methods have been released for major continental populations. However, few reports refer to sub-populations within the East Asian population using hundreds of ancestry informative SNPs (AISNPs). In this study, we developed a 308-AISNP panel (EASplex NGS DNA panel) using multiplex PCR and next generation sequencing (NGS). This panel included 56 SNPs relevant for the continent-level ancestry inference and 252 Japanese-, Korean-, and/or Han Chinese-specific AISNPs to address the ancestry inference of global populations and regional populations among Japanese (JPT), Korean minority (CHK), and Han Chinese (CHH). A total of 87 CHK and 59 CHH samples were used to check the performance of the EASplex NGS DNA panel. By analyzing 146 profiles of samples with JPT and CHH data from Beijing and South China in 1000 genomes project, the following results were obtained: (1) the 146 tested samples were correctly assigned to the East Asian group; (2) the paired population assignment rate was 99.73% for JPT and CHH, 95% for JPT and CHK, and 90.11% for CHK and CHH; and (3) the whole population assignment was 92.14% for the JPT, CHK, and CHH data. Overall, the EASplex NGS DNA panel displayed informativeness for continental ancestry inference and regional ancestry inference among JPT, CHH, and CHK and has the potential for use in forensic and genetic population studies.

HGG-45. Characterization of spinal diffuse midline gliomas, H3 K28M-mutant

Diffuse midline gliomas (DMGs) are malignant gliomas that arise in the midline structures of the central nervous system. Due to their aggressive and diffuse growth and a two-year survival rate of less than 10%, DMGs are assigned to CNS WHO grade 4. Depending on the localization, median age of patients is about 11‒20 years. Genetically, most tumors are defined by a K28M-mutation in one of the highly homologous genes encoding histone protein H3. Since DMGs most frequently occur in pons and thalamus, comparatively little is known about spinal DMGs. Therefore, we histologically, molecularly, and clinically characterized spinal DMGs and analyzed, in which aspects they differ from DMGs of other localizations. Our cohort currently consists of 25 spinal DMGs and 40 pontine/thalamic reference cases. Histological, immunohistochemical and molecular analyses (DNA methylation, DNA panel sequencing) were done from FFPE tissue. Spinal DMGs were histologically very heterogeneous, both regarding different areas of single tumors as well as in comparison to other spinal and reference cases. First cluster analyses of DNA methylation data indicated a separation into three main clusters enriched for pontine, thalamic or spinal cases. The cluster enriched for spinal cases contained many tumors from elderly patients. Overall, mean age of patients with spinal DMGs was 28 years. Patients were significantly older than those with pontine DMGs. 19/20 spinal DMGs were H3-3A K28M-mutant, while one tumor had an H3-2B mutation. 4/19 (21%) spinal DMGs had mutations in FGFR1, and 6/10 (60%) in NF1. Three tumors had KRAS or BRAF mutations. In summary, first analyses suggest slight histological differences of spinal DMGs compared to DMGs of other localizations. Preliminary cluster analyses of DNA methylation data showed an enrichment of clusters for different localizations. About one third of spinal DMGs had mutations in a gene associated with the MAPK-signaling pathway.

Detection of multiple types of cancer driver mutations using targeted RNA sequencing in NSCLC.

e15043 Background: DNA NGS sequencing has been widely used as a companion diagnostic method for matching NSCLC patients with appropriate personalized target therapy. RNA-based NGS has been proved to be valuable in detecting fusion and exon skipping mutations and therefore recommended by NCCN guidelines for these mutation types. It would be helpful to have a diagnostic method that suits different types of clinically actionable mutations in a single tube. Methods: We developed an RNA-based hybridization panel targeting actionable driver oncogenes in solid tumors. Experimental and bioinformatics pipelines were optimized for detection of fusion, SNV and indel mutations, as well as gene expression quantification. Reference materials were used for analytical validation of the panel, and 1253 FFPE samples from NSCLC patients were analyzed by DNA panel sequencing and RNA panel sequencing in parallel to assess the performance of the RNA panel in detection of multiple types of clinically actionable mutations. Results: Analytical validation showed a detection specificity of 100.0% for SNVs and fusions. The targeted RNA panel achieved a 1.45-3.15 copies/ng limit of detection (LOD) for SNVs and a 0.21-6.48 copies/ng LOD for fusions. Gene expression analysis revealed a correlation greater than 0.9 between the RNA-seq and targeted RNA panel results. Among 1253 NSCLC FFPE samples, multiple mutation types were called at both DNA and RNA levels and compared between the two assays. Twenty-one fusion and six METex14 skipping events were only detected by the RNA panel. The positive percent agreement (PPA) and positive prediction value (PPV) were 98.08% and 98.62% for targetable SNVs and 98.15% and 99.38% for targetable Indels, respectively. We also explored the relationship of RNA expression with gene copy number and protein expression. The RPKM (reads per kilobase per million mapped reads) of EGFR transcripts exhibited a linear relationship with copy number, whereas MET gene expression seemed to be regulated in a more complexed manner. In IHC analysis, all MET IHC 3+ samples had significantly higher RPKM levels than samples with MET IHC level of 2+/1+. Conclusions: Parallel DNA and RNA systematic analysis demonstrated the accuracy and robustness of the RNA sequencing panel for detection of multiple types of clinically actionable mutations. The simplified experimental workflow, lowered cost and sample consumption, along with the superior performance in simultaneous detection of multiple types of mutations will make RNA panel sequencing an effective method in clinical testing for NSCLC.

Mutational spectrum of BRCA1/2 genes in Moroccan patients with hereditary breast and/or ovarian cancer, and review of BRCA mutations in the MENA region.

Breast cancer (BC) is the most common form of female cancer around the world. BC is mostly sporadic, and rarely hereditary. These hereditary forms are mostly BRCA1-andBRCA2-associated hereditary breast and ovarian cancer syndrome. BRCA1 and BRCA2 genes are large and had some recurrent mutations specific to some populations. Through this work we analyze the most recurrent mutations in Moroccan population and compared them to a large review of other BRCA1/2 spectrum mutations in the MENA region. We report in this work a series of 163 unrelated patients (the largest series of Moroccan patients) with familial breast and/or ovarian cancer, selected among patients referred to our oncogenetic outpatient clinic, from 2006 to 2021. To identify genetic variants in these two genes, different genetic analysis strategies have been carried out, using Sanger Sequencing DNA or Target Panel Sequencing. Pathogenic variants were identified in 27.6% of patients. The most frequent mutation identified in our patients was the c.1310_1313delAAGA, BRCA2 (33%), and three other mutations seem more frequent in the Moroccan population (33%) of all reported patients: c.798_799delTT, BRCA1; and c.3279delC, BRCA1; and c.7234_7235insG in BRCA2 gene. Through this work, we emphasize the importance of screening for BRCA1 and BRCA2 recurrent mutations in Moroccan patients. Other MENA (MENA: English-language acronym referring to the Middle East and North Africa region) countries had also some recurrent BRCA mutations, which will allow a fast and unexpensive first line genetic analysis and a precise molecular diagnosis. This will allow an adapted follow-up of the patients and a pre-symptomatic diagnosis of their relatives.

Improving care of melanoma patients through efficient, integrated cellular-molecular pathology workflows using tissue samples with low tumour nuclear content

AimsThe aim of this quality improvement project was to improve the turnaround time of B-raf proto-oncogene (BRAF) mutation testing in patients with malignant melanoma to support oncologists in making timely...

Clinical Utility of Implementing a Frontline NGS-Based DNA and RNA Fusion Panel Test for Patients with Suspected Myeloid Malignancies.

The use of molecular genetic biomarkers is rapidly advancing to aid diagnosis, prognosis, and clinical management of hematological disorders. We have implemented a next-generation sequencing (NGS) assay for detection of genetic variants and fusions as a frontline test for patients suspected with myeloid malignancy. In this study, we summarize the findings and assess the clinical impact in the first 1613 patients tested. All patients were assessed using NGS based Oncomine Myeloid Research Assay (ThermoFisher) including 40 genes (17 full genes and 23 genes with clinically relevant "hotspot" regions), along with a panel of 29 fusion driver genes (including over fusion 600 partners). Among 1613 patients with suspected myeloid malignancy, 43% patients harbored at least one clinically relevant variant: 91% (90/100) in acute myeloid leukemia patients, 71.7% (160/223) in myelodysplastic syndrome (MDS), 77.5% (308/397) in myeloproliferative neoplasm (MPN), 83% (34/41) in MPN/MDS, and 100% (40/40) in chronic myeloid leukemia patients. Comparison of NGS and cytogenetics results revealed a high degree of concordance in gene fusion detection. Our findings demonstrate clinical utility and feasibility of integrating a NGS-based gene mutation and fusion testing assay as a frontline diagnostic test in a large reported cohort of patients with suspected myeloid malignancy, in a clinical laboratory setting. Overlap with cytogenetic test results provides opportunity for testing reduction and streamlining.

Cross-cultural validation of stool Based Colorectal cancer screening methods in the North West of Iran

BackgroundGlobally, colorectal cancer (CRC) is the third most common cancer and the second leading cause of death from cancer. Incidence and mortality from CRCboth can be reduced and prevented using screening and early detection programs. The current study aimed to assess the feasibility of the colorectal cancer screening program in Northwest of Iran. MethodsThe study designed as a cross-cultural analytic study, to evaluate the diagnostic accuracy of stool-based tests compared with colonoscopy, during 2016–2020. All individuals first were assessed with our CRC risk assessment tool, then eligible volunteers entered the study. Colonoscopy was performed on all participants, also stool-based tests including traditional guaiac, high-sensitivity guaiac-based, fecal immunochemical test (FIT), and multitarget stool DNA (Mt-sDNA) panel tests were performed. ResultsMt-sDNA test panel had a sensitivity of 77.8% (95% CI: 40–97.2)for detecting colorectal cancer with a specificity of 91.2% (95% CI:85.4–95.2). The FIT test alone had a lower sensitivity (66.7%; 95% CI:29.9–92.5) and almost the same specificity of 93.9% (95% CI: 88.7–97.2) for cancer detection. Mt-sDNA test had better diagnostic accuracy than the FIT (AUC = 0.85 vs 0.80), and is a more useful screening test. Positive and negative predictive values for cancer detection for both Mt-sDNA and FIT tests were almost the same results, however Mt-sDNA test had better NPV results than the FIT test alone. ConclusionOur results showed that both Mt-sDNA panel and the FIT test had acceptable cut-off points for cancer detection, however, Mt-sDNA test had better diagnostic accuracy.

Evaluation of the Clinical Utility of Genomic Profiling to Inform Selection of Clinical Trial Therapy in Salivary Gland Cancer.

Simple SummarySalivary gland cancer is rare and there is a need to develop new and effective drug therapies. New drugs are in development in the recurrent and metastatic setting that target specific changes within a cancer, some of which can be detected through sequencing of the cancer DNA. This study addressed how useful the DNA sequencing of cancer samples is to inform the decision of which drug therapy within a trial is the best match for each individual patient. We found that using focused DNA panels, including small numbers of genes, helped to match just over one in four patients with salivary gland cancer to drug therapies. The matching rate of the focused panel varied by subtype and was least useful in adenoid cystic carcinoma (ACC), at 7%. However, in ACC, larger gene panels had added value, identifying matched trial therapies in 40% of cases.For most patients with salivary gland cancer, there are no effective standard systemic therapies. Although clinical trials of biomarker-led drug therapies have delivered significant recent advances, there remains a need to understand the clinical utility of genomic profiling of cancer as a means to match patients with recurrent or metastatic salivary gland cancer to clinical trial therapies. In total, 209 patients with salivary gland cancers were profiled with 24 gene (n = 209)) and >325 gene (n = 32) DNA-based next-generation sequencing panels. A retrospective systematic evaluation was performed to identify the frequency of available matched drug therapies within clinical trials based on the results. The matches were then stratified based upon the level of evidence supporting the drug–biomarker combination being investigated using the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) to determine the strength of the clinical rationale for each gene–drug match identified. DNA-based next generation sequencing (NGS) analysis was successful in 175/209 (84%) patients with salivary gland cancer. Using the 24-gene NGS panel, actionable alterations were identified in 27% (48/175) patients. Alterations were most frequent in salivary duct carcinoma (88%) characterized by TP53 and/or PIK3CA mutations, with matched trials available for 63% (10/16). In ACC, biomarker-matched trials were available for 7% (8/115), and no genomic alterations were found in 96/115 (83%) of ACC patients. TP53 was the most frequently altered gene across all subtypes; however, there were no trials recruiting based on TP53 status. In 32 ACC patients with no genomic alterations using the 24-gene panel, a broader (>325 gene) panel identified alterations in 87% (27/32) of cases with biomarker-matched trials available in 40% (13/32) cases. This study identified that genomic profiling using focused (24-gene) NGS panels has potential utility in matching to trial therapies for most patients with non-ACC salivary gland cancer. For patients with ACC, broader genomic profiling has demonstrated added clinical utility. We describe the application of an approach to classification of levels of evidence which may be helpful to inform the clinician and patient decision making around the selection of clinical trial therapies.