Mutation Detection Assay Research Articles

Detection Of CCR5 Delta-32 Mutation Using High-Resolution Melting Curve Analysis: Challenges and Facts.

The C-C chemokine receptor type 5 (CCR5) is a major co-receptor for human immunodeficiency virus (HIV). Some individuals carry the CCR5 delta-32 genetic polymorphism. People with homozygous CCR5 delta-32 gene are nearly completely resistant to HIV-1 infection. High-resolution melting curve (HRM) analysis is a post-PCR technique utilized for identifying genetic variations in a quick, affordable, and closed-tube assay. The objective of this study was to develop an HRM assay for easy detection of delta-32 mutations. DNA was extracted from peripheral blood mononuclear cells. HRM was performed to detect delta-32 mutation. The study investigated the impact of various factors, including annealing temperature, template concentration, touchdown PCR, additives, amplicon size, and program settings, on HRM Tm differentiation. It was expected that there would be a 4°C Tm difference between amplicons with and without delta-32 mutation, but the test showed a difference of only 2.3°C. In attempts to identify heterozygote delta-32 variants, a Tm difference of only 0.4°C could be achieved. Various modifications were applied, such as adjusting the template concentration, using touchdown PCR, and adding DMSO and glycerol. However, none of these changes helped to differentiate the Tm effectively, especially in delta-32 heterozygote samples. The HRM test identified four samples with heterozygote mutations in each HIV-infected (8.89%) and control (5.72%) groups. More importantly, this study showed that identifying the delta-32 mutation of the CCR5 gene using HRM assay is not as straightforward as previously suggested in some literature, and it requires special setup conditions.

Development and validation of a multi-marker liquid bead array assay for the simultaneous detection of PIK3CA and ESR1 hotspot mutations in single circulating tumor cells (CTCs)

BackgroundPIK3CA and ESR1 mutations are associated with progression and therapy resistance in metastatic breast cancer (MBC). CTCs are highly heterogeneous and their analysis at single cell level can provide unique information for mutational profiling and the existence of different sub-clones related to tumor progression. We have developed a novel multi-marker liquid bead array assay based on combination of an enzymatic mutation enrichment method, multiplex PCR-based assay, and liquid bead array technology for the simultaneous detection of PIK3CA and ESR1 hotspot mutations in liquid biopsy samples. We focus on single CTCs, however the assay can be used for bulk CTC and ctDNA analysis. Materials and methodsSingle CTCs were isolated from an ER+/HER2+ MBC patient from CellSearch® cartridges using the VyCAP Puncher System and subjected to whole genome amplification followed by nuclease-assisted minor-allele enrichment with probe-overlap (NaME-PrO) enrichment. The assay was validated for analytical sensitivity and specificity for the simultaneous detection of PIK3CA (E545K, E542K, H1047R, H1047L) and ESR1 (Y537S, Y537C, Y537N, D538G, L536H) mutations in single CTCs, while its clinical performance was evaluated on 22 single CTCs and three single white blood cells (WBCs). ResultsThe developed multi-marker liquid bead array assay is novel, highly specific and sensitive for both mutation panels. The assay can reliably detect mutation-allelic-frequencies (MAFs) as low as 0.1 %. The presence of PIK3CA and ESR1 mutations was detected in 13.6 % and 72.7 % of single CTCs, respectively. The developed assay is sample-saving since it requires only 2 μL of amplified DNA to check for nine hotspot PIK3CA and ESR1 mutations in a single cell. The developed liquid bead array assay (Luminex, US), based on a 96 microwell plate format, enables the simultaneous analysis of 96 single cells. ConclusionsThe developed novel multi-marker liquid bead array assay for the simultaneous detection of PIK3CA and ESR1 hotspot mutations in single CTCs is highly specific, highly sensitive, high-throughput, and sample-, cost-, and time-saving. This multi-marker liquid bead array assay can be extended to detect up to 100 mutations in many genes at once and can be applied for bulk CTC and ctDNA analysis.

Assessment of in vivo chemical mutagenesis by long-read sequencing.

Evaluating the mutagenic properties of chemicals is crucial for understanding their potential cancer risks. Recent Illumina-based error-corrected sequencing techniques have enabled the direct detection of mutations induced de novo by mutagens. However, as the Illumina platform lacks intrinsic error-correction capabilities, complex library preparations and bioinformatic processes are necessary to identify these rare mutations. In this study, we evaluated whether long-read PacBio-based HiFi sequencing (HiFi seq), which has integrated error-correction, can detect de novo mutations induced by mutagens in C57BL/6 mouse tissues. Using HiFi seq, dose-dependent increases in mutation frequencies were found in tissues from mice exposed to 7,12-dimethylbenz[a]anthracene, procarbazine, and N-propyl-N-nitrosourea. Furthermore, the mutational signatures derived from these exposures were consistent with those previously reported for these mutagens. This study demonstrates that HiFi seq can complement established mutation detection assays to facilitate the identification of hazardous compounds.

Evaluation of a New Closed-System Automated RT-qPCR Assay for the Rapid Detection and Monitoring of Common Nucleophosmin Mutations in Patients with Acute Myeloid Leukemia.

Quantitative assessment of nucleophosmin 1 (NPM1) mutation status is integral to evaluating measurable residual disease (MRD) in NPM1-mutated acute myeloid leukemia (AML) patients. In a retrospective study, leftover peripheral blood (PB) specimens (n = 40) which were collected for routine clinical diagnostic evaluations of AML disease burden were tested by both a novel automated RT-qPCR quantitative NPM1 assay (Xpert NPM1 mutation assay) and the NPM1 mutA, mutB&D MutaQuant kit. Based on a Deming regression analysis, there was a high correlation (slope = 0.92; intercept = 0.12; Pearson's r = 0.982) between the quantitative results of the Xpert NPM1 mutation assay and the NPM1 mutA, mutB&D MutaQuant kit. The Xpert test quantitative results are thus highly correlated with the comparator method and the former has potential as a useful alternative for the monitoring of AML patients with a known NPM1 mutation.

Validation of a novel NGS based BCR::ABL1 kinase domain mutation detection assay in Indian cohort

The efficacy and treatment outcome of a CML patient are heavily dependent on BCR::ABL1 kinase domain (KD) mutation status. Next-generation sequencing technology is a bright alternative to the previously used sanger sequencing method due to its global presence in diagnostic setups, massive parallel sequencing ability, and far better sensitivity. In the present study, we have demonstrated a new protocol for kinase domain mutation analysis using the next-generation sequencing (NGS) method using the ion torrent sequencing platform. This protocol uses RNA as the starting material, followed by nested PCR to amplify the fusion transcript, which is subsequently used as a template for NGS. Initial validation and comparison of this assay with the sanger sequencing (SS) method yielded 95.23% agreement. CML samples (n = 121) with a failure to TKI response were subjected to this newly developed NGS-based assay to detect KD mutations, from which samples were found to have mutations with a sensitivity ranging from 2.32 to 93.41%. A total of 34.71% of samples (n = 42) were found to be positive for one or more KD mutations, whereas 65.29% of samples (n = 81) were found to be negative. Nine samples out of 42 positive samples, i.e., 21.42%, were found to have compound mutations. This is one of the first studies from India, which includes more than 160 samples and is analyzed by the NGS approach for KD mutation analysis.

Detection of Asymptomatic Sickle Cell Hemoglobin Carriers and Fetal Hemoglobin Regulating Genetic Variants in African Descendants from Oaxaca, Mexico.

Sickle cell anemia has been classified as a noninfectious neglected tropical disease and, although not exclusively, affects African descendants more frequently. This study aimed to detect asymptomatic sickle cell hemoglobin carriers (HbAS) in marginalized and vulnerable populations during a public health screening in African descendants from Oaxaca, Mexico, and to validate an amplification refractory mutation system (ARMS)-PCR methodology to detect fetal-hemoglobin (HbF)-regulating genetic variants in BCL11A toward affordable routine association of single nucleotide variants (SNVs) with HbF concentrations. To this aim, hemoglobin variants were detected by acidic citrate agar and alkaline cellulose acetate electrophoreses. SNVs in the hemoglobin subunit beta gene (HBB) were identified by the β-globin mutation detection assay (β-GMDA) and ARMS-PCR, respectively, and validated by Sanger sequencing. The association between genotypes and HbF concentrations was evaluated using Spearman's correlation coefficient. The results obtained during a directed screening in 140 self-identified African descendants revealed 42 HbS-carriers (30%), of which 39 showed normal total hemoglobin concentrations (92.8%), only 3 presented anemia (7.2%), and 9 showed quantifiable HbF concentration (21.4%). As validated by Sanger sequencing, the designed ARMS-PCR efficiently detected homozygous and heterozygous variants in BCL11A. In a cohort of 42 heterozygous (HbAS) and 27 healthy (HbAA) individuals from the same population, only one SNV (rs766432) showed statistically significant association with increasing HbF concentration, and two new unrelated homozygous silent variants were identified. This study reveals the need to raise coverage of HbS screening in vulnerable populations and shows a feasible low-cost ARMS-PCR methodology to determine the presence of SNVs in quantitative trait loci affecting HbF.

Dual-centre evaluation of the FluoroType MTBDR version 2 assay for detection of Mycobacterium tuberculosis complex and resistance-conferring mutations in pulmonary and extrapulmonary samples from Denmark, Germany and Sierra Leone

ObjectivesWe evaluated the ability of FluoroType MTBDR version 2 (FTv2; Hain Lifescience), a second-step real-time PCR assay, to simultaneously detect Mycobacterium tuberculosis complex (MTBC) DNA and mutations conferring resistance to rifampicin (RIF) and isoniazid (INH), in pulmonary and extrapulmonary samples from patients and compared them with corresponding cultures. MethodsFTv2 MTBC was evaluated on 1815 and 432 samples from Denmark (DK) and Germany (DE), respectively. RIF and INH resistance mutations were assessed in the German samples and 110 samples from Sierra Leone and subsequently compared to phenotypic antimicrobial susceptibility testing and a composite reference DNA (CRD) based on the GenoType MTBDR line-probe assay and Sanger sequencing or whole-genome sequencing. ResultsOf the 584 (557 smear-negative) Danish and 277 (85 smear-negative) German sputum samples, 42 (16) and 246 (54) were culture positive, and 44 (18) and 222 (35) were FTv2 positive, providing an FTv2 sensitivity and specificity of 0.86 (0.63) and 0.98 (DK), 0.90 (0.65) and 1.00 (DE), respectively. The count, sensitivities, and specificities for all pulmonary samples were 1434, 0.79, and 0.99 (DK) and 347, 0.86, and 1.00 (DE), respectively; for extrapulmonary samples, 381, 0.33, 0.99 (DK) and 83, 0.50, and 1.00 (DE). The valid count, sensitivity, and specificity compared with CRD for detecting resistance mutations were RIF 355, 0.99, 0.96, and INH 340, 1.00, and 0.98, respectively. DiscussionFTv2 reliably detects MTBC DNA in pulmonary and extrapulmonary samples and detects resistance mutations for INH and RIF resistance in inhA promoter, katG, and rpoB genes.

Abstract 5038: Validation of a comprehensive next-generation sequencing liquid biopsy assay for clinical diagnostics and clinical trial applications

Abstract Liquid biopsy next generation sequencing (NGS) provides a powerful non-invasive approach to detect solid tumor derived somatic variants in a massively parallel manner. Liquid biopsy NGS has rapidly become an invaluable choice of testing technologies for clinical utility where invasive tissue biopsy is inaccessible and/or inadequate for molecular characterization. We present here a targeted NGS gene panel assay designed and validated specifically for liquid biopsy characterization. The assay was designed to test cell free DNA and cell free RNA from blood plasma for detection of single nucleotide variants (SNV), insertion/deletion (Indel), copy number variants (CNV), and gene fusions present in 52 most commonly mutated genes in cancers. The validation was performed to assess assay accuracy, specificity, sensitivity, repeatability, and reproducibility, with including pre-characterized reference controls, retrospective plasma samples from cancer patients, and prospectively-collected clinic blood specimen. Triplicates were included and testing was performed at different times and by different operators to assess the assay precision. Over 100 clinic blood specimens were collected in Streck cfDNA tubes from multiple trial centers, including treatment naïve phase III-IV patients with solid tumor (lung cancer, breast cancer, brain cancer, prostate cancer, kidney cancer, melanoma, etc) as well as heathy donors, processed within 7 days for plasma separation and total nucleotide acid (TNA) extraction, and assessed by the NGS assay for mutation detection. The identified mutations and wild-types were verified with orthogonal ddPCR. Assay sensitivity as low as 0.1% for SNV and Indel, 1.3 fold change for CNV, and 10 copies for gene fusion were observed, with near-perfect assay specificity (>99.99%) at these sensitivity levels. In conclusion, a targeted NGS liquid biopsy assay was analytically validated under medical oversight, with a demonstrated rigor of the test by its high sensitivity/specificity and robust reproducibility. The validated assay has been utilized for clinical diagnostics and to support research and development efforts in clinical trials. Citation Format: Xin-Xing Tan, Tricia Peters, Meredith Berry, Kimberly Barber, Kristyn Jeter, Brigitte Lovell, Paula Elizondo, Yanglong Mou, Brad Thomas, Heng Xie, Jiannan Guo. Validation of a comprehensive next-generation sequencing liquid biopsy assay for clinical diagnostics and clinical trial applications [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 5038.

Abstract 3750: Dual isolation and profiling of circulating tumor cells and circulating tumor DNA from a single liquid sample using the Genesis Cell Isolation System and Droplet Digital PCR

Abstract Introduction: Recent advances in technology support the use of liquid biopsy as a noninvasive method for cancer monitoring and diagnosis. Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) are both regarded as key liquid biopsy biomarkers, offering significant disease-related molecular insights. Despite their potential, dual isolation and profiling have been challenged in a clinical setting by the lack of established platforms and optimized protocols that support this approach. The Genesis System with Celselect SlidesTM captures CTCs based on size and deformability, then the enriched cells can be recovered for subsequent downstream analysis. Concurrently, Droplet Digital PCR (ddPCRTM) can be utilized to interrogate cell-free DNA (cfDNA) to determine the presence of a range of DNA aberrations present in ctDNA. This study, using a model lung CTC-ctDNA sample, illustrates the feasibility of this dual-biomarker approach to detect cancer-associated nucleic acid mutations simultaneously with CTC enumeration, using commercially available kits and instruments. Methods: To model lung cancer samples, blood samples were prepared by spiking in two model circulating markers, cultured cancer cells (model CTCs, human ㅣlung cancer cell line A549) and fragmented genomic DNA containing EGFR mutations (model ctDNA, multiplexed 23 ctDNA [~145 bp band > 95%]), into whole blood from a healthy donor prior to enrichment/extraction. Plasma isolation from the whole blood model samples was performed using either two-step centrifugation or Ficoll-Paque PLUS solution for plasma/buffy coat separation. The extracted plasma layer was used for ctDNA separation, while the remaining cell layer was used for CTC isolation on the Genesis System with a modified protocol. Results: The Genesis System isolated 78-79% of spiked cancer cells in whole blood at a concentration of 40 cells/ml. Despite additional plasma separation steps and liquid handling, the system isolated CTCs spiked in with minimal cell loss (<6%). With an optimized ctDNA extraction, more than 70% of spiked ctDNA in blood samples in the size range of 120-220 bp was extracted. Using the Bio-Rad QX200 ddPCR System and ddPCR EGFR T790M Mutation Detection Assay, blood samples with the model ctDNA spiked in showed positive droplets (17 copies) for EGFR T790M while control blood samples without model ctDNA spiked in showed no positive droplets. Discussion and Conclusions: This work illustrates an optimized protocol for the dual isolation and profiling of CTCs and ctDNA from a single blood sample by using an automated CTC isolation platform and high-sensitivity ddPCR based ctDNA mutation detection. This protocol enables comprehensive liquid biopsy studies using a single blood sample from cancer patients with readily available instruments and kits, which can be applied to many other cancers. Citation Format: Yoon-Tae Kang, Abiodun Bodunrin, Errile Pusod, Kris Simonyi, Adam Corner, David Coe, Michelle Racey, Elizabeth J. Dreskin. Dual isolation and profiling of circulating tumor cells and circulating tumor DNA from a single liquid sample using the Genesis Cell Isolation System and Droplet Digital PCR [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 3750.

Abstract 7295: A novel XNA technology-based assay to detect JAK2 V617F mutation by real-time PCR

Abstract The Janus kinase 2 (JAK2) gene is located on chromosome 9p24.1 and encodes a non-receptor tyrosine kinase that plays a central role in cytokine and growth factor signaling. The JAK2 protein is especially important for controlling the production of blood cells from hematopoietic stem cells. In fact, the JAK2 mutation at amino acid 617 (Valine 617 to Phenylalanine, V617F) is the most frequently detected mutation in myeloproliferative neoplasms (MPN), including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). This dominant gain-of-function V617F mutation results in constitutive tyrosine phosphorylation activity, leading to uncontrolled blood cell production, including increased numbers of erythrocytes, neutrophils, and platelets. To detect the JAK2 V617F mutation in DNA from patient blood samples, we developed a unique real-time PCR assay using our proprietary XNA technology that enables the assay to selectively amplify the mutant sequence by using a synthetic DNA analog XNA (Xenonucleic Acid). The JAK2 V617F mutation detection assay is designed to detect a valine-to-phenylalanine mutation at amino acid 617 (V617F). PCR primers, TaqMan probes, and XNA were designed for the JAK2 V617F mutation, along with primers and probes for an internal control gene in the duplex setting. The analytical performance of the assay was verified and validated using a variety of control samples. The results revealed that the XNA completely suppressed the amplification of wildtype sequence while only the V617F mutant sequence was amplified. The JAK2 V617F mutation detection assay is highly reproducible with intra- and inter-assay coefficients of variation of less than 10%. Results for the assay’s analytical sensitivity indicated that V617F could be detected with about 0.25% mutant allele frequency in 10 ng DNA input. In addition, no significant cross-amplification between V617F and V617I was observed. Thus, the JAK2 V617F mutation detection assay is specific for the V617F mutation. The JAK2 V617F mutation detection assay, using XNA-based technology, provides high sensitivity and specificity to detect the JAK2 V617F mutation. Thus, this assay would be a useful tool for clinical decision-making in determining the presence of the JAK2 V617F mutation in DNA from patient blood samples. Citation Format: Shuo Shen, Robert Brown, Daniel Kim, Larry Pastor, Andrew Y. Fu, Pushpinder Kaur, Alisha Babu, Wei Liu, Aiguo Zhang, Hiromi Tanaka, Michael Y. Sha. A novel XNA technology-based assay to detect JAK2 V617F mutation by real-time PCR [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 7295.

Abstract 6423: KRAS mutation detection by Sanger sequencing using the SeqStudio Flex capillary electrophoresis instrument

Abstract The detection of mutations in the KRAS gene highly associated with cancer is one of the most widely used Sanger sequencing capillary electrophoresis (CE) applications in molecular diagnostics. In addition to their traditional role in cancer diagnostic, KRAS mutations have recently gained additional relevance as pharmacogenomics (PGx) markers for a significant number of new oncology therapeutics. KRAS mutation detection assays are used as companion diagnostics (CDx) for these cancer treatments. Analysis by Sanger Sequencing of KRAS mutations is cost effective and lends itself for use in resource limited healthcare settings. While there are currently no commercial kits for targeted sequencing of the KRAS mutation hotspots available, the online Applied Biosystems Primer Designer™ Tool (thermofisher.com) allows standardization of the PCR primer design between labs and repeat orders of the KRAS assays by using these commercially available assay ID numbers. Here we demonstrate the use of Primer Designer KRAS mutation detections assays for mutation in codon 12, 13 and 61 totaling to 8 allele variants. The data was generated on the SeqStudio Flex CE instrument using reference standard DNA as well as DNA extracted from FFPE solid tumor samples. We show accuracy of variant call (OPA 100% (64/64)) and concordance (OPA 98.3% (59/60)) in a side-by-side comparison of the SeqStudio Flex with the legacy Model 3500 Genetic Analyzer instrument using a set of commercially available (Horizon Discovery) KRAS reference DNA samples. Primary solid tumor samples are processed to Fresh Frozen Paraffin Embedded samples (FFPE) for further disease marker evaluation. These samples are stable for long term at ambient temperatures and provide the opportunity to evaluate prospective biomarkers at large scale to understand their potential utility. Discovery Life Sciences has generated a large-scale biorepository of human biospecimen, including FFPE, plasma/sera, buffy coat, and PBMCs. Archival FFPE samples from oncology indications associated with KRAS mutations, such as non-small cell lung cancer and colorectal cancer, were analyzed and identified samples with KRAS mutations, demonstrating the potential diagnostic utility of these assays. Finally, cell-free (cf) DNA from double spun plasma from relevant indications was also successfully evaluated for KRAS mutations, highlighting the potential for these assays in liquid biopsy studies. The study demonstrates the robustness of the Primer Designer KRAS mutation detection sequencing assays using reference standard DNA as well as DNA derived from FFPE DNA and cfDNA from patient derived tumor samples. For Research Use Only. Not for use in diagnostic procedures. Citation Format: Achim Karger, Ami Patel, Kaylee Tseng, Camila Ornelas, Mary Napier, Rod Beck, Kerri Collwell, Shawn Fahl, Carole Bornarth. KRAS mutation detection by Sanger sequencing using the SeqStudio Flex capillary electrophoresis instrument [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 6423.

Abstract 2430: Enhancing urine-based cfDNA detection for prostate cancer diagnosis through increased urine input volume

Abstract Introduction: Cell-free DNA (cfDNA) extracted from urine has created new opportunities in non-invasive cancer diagnostics, particularly for prostate cancer. Detecting cfDNA in urine can be challenging due to its inherently low concentration. Increasing the input volume of urine addresses this limitation, enhancing the sensitivity of cfDNA detection. This study explores the benefit of collecting larger volumes of urine spiked with a TP53 mutation and the corresponding increase in assay sensitivity for early prostate cancer diagnosis and monitoring. Methods: Pooled urine from healthy donors was collected, preserved, processed, and extracted from 10 mL, 20 mL, 30 mL, 40 mL, and 50 mL inputs (with four replicates each) using the Revolution Max 20 cfDNA Extraction kit. Replicate samples were also extracted using a MagMAX cfDNA Isolation kit from Thermo Fisher Scientific. All samples were spiked with a cfDNA standard containing TP53 R58L mutation. The quantity and quality of extracted cfDNA were determined using the Agilent TapeStation system with the Cell-free DNA ScreenTape assay and qPCR mutation detection assay. Results: The Revolution Max 20 cfDNA kit consistently delivered a higher yield of cfDNA, demonstrating excellent extraction efficiency and quality, as shown by the Agilent Cell-free DNA ScreenTape assay. Notably, the Revolution Max 20 cfDNA kit exhibited a linear increase in yield as the sample volume grew from 10 mL to 50 mL. The MagMax kit did not provide this yield linearity. Furthermore, both methods successfully maintained the integrity of cfDNA fragmentation, which was confirmed through the Agilent Cell-free DNA ScreenTape assay. Conclusion: Compared to the MagMax kit, the Revolution Max 20 cfDNA kit outperforms in extracting cfDNA with high efficiency, as shown by the Agilent Cell-free DNA ScreenTape and the qPCR assay. The Revolution Max 20 cfDNA kit offers the unique advantage of accommodating up to 50 mL of urine in a single extraction. As input volume increases, it consistently produces high cfDNA yields while maintaining quality. In contrast, the MagMax kit is limited to an input volume of only 10 mL, necessitating the cumbersome process of dividing a 50 mL urine sample into five separate extractions and pooling the eluates. This scheme resulted in lower yields. The Agilent Cell-free DNA ScreenTape assay is a valuable tool for quickly and accurately assessing the %cfDNA quality metric. Its minimal sample volume requirement makes it an efficient quality control method for determining cfDNA samples before performing downstream testings. The enhanced capability of the Revolution Max 20 kit to yield more significant quantities of high-quality cfDNA from urine samples can profoundly impact liquid biopsy test sensitivity and the early detection of prostate cancer, potentially revolutionizing the diagnostics process. Citation Format: Nafiseh Jafari, Annika Dorn, Jason Saenz, Lauren Lee, Carlos Hernandez, Andrew Dunnigan, Mayer Saidian. Enhancing urine-based cfDNA detection for prostate cancer diagnosis through increased urine input volume [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 2430.

Abstract 5042: Urine as a non-invasive proxy for plasma in prostate cancer-related liquid biopsy applications

Abstract Introduction: The non-invasive collection of urine renders it an attractive and pragmatic substitute for plasma in liquid biopsy applications, fostering the creation of diagnostic methods that are more patient-friendly and less cumbersome for clinicians. This study investigates the feasibility of urine-derived cfDNA as a non-invasive option for acquiring vital diagnostic insights, further enhancing the liquid biopsy field. Methods: Paired male first void urine (FVU) and venous blood samples were collected from healthy donors (n=40) using Colli-Pee UAS devices (Novosanis) and BD K2EDTA Vacutainer tubes, respectively. Out of these, 20 paired urine and blood samples were spiked with 10 ng of cfDNA reference standard containing the KRAS p.G12V mutation. ~35 ml of urinary cell-free supernatant and ~3.5 ml of plasma were obtained after centrifugation of FVU and blood sample, respectively, and used as input material for cell-free nucleic acids extraction using the nRichDX Revolution Max20 cfDNA Isolation Kit. The extracted cfDNAs profile was assessed on 4200 TapeStation System, Agilent, using cfDNA ScreenTape. Extracted nucleic acids from urine samples were subjected to a qPCR assay to quantify endogenous human cfDNA content using 2X iTaq Universal SYBR Mastermix (Bio-Rad). Human cfDNA quantity was assessed using Ct values obtained from the qPCR assay. The actionable cfDNA molecules recovery was determined by qPCR mutation detection assay using TaqMan Genotyping. Results: Male FVU collected in Colli-Pee UAS device showed the presence of 100-250 bp cell-free DNA fragments similar to plasma obtained from whole blood collected in 10 ml vacutainer tubes as demonstrated by the Agilent cfDNA ScreenTape analysis. The cfDNA yield was similar when comparing one tube of blood (~3.5 mL of plasma) to one Colli-Pee of urine (~35 mL) shown by endogenous cfDNA qPCR assay. Additionally, the amplifiability of the KRAS G12V mutation was consistent in both plasma and urine samples, with comparable Ct values. Conclusion: The nRichDX Revolution Sample Prep System demonstrates the ability to extract cfDNA from both plasma and urine samples, with comparable extraction efficiency observed between matched samples from the same donor. This study provides evidence supporting the viability of first void urine samples as a non-invasive alternative for prostate cancer-related liquid biopsy applications. It indicates that cfDNA can be recovered from a sample collected with a single BCT or Colli-Pee UAS urine collection device. Future investigations will be required to assess clinical samples and biomarkers to establish a robust correlation between cfDNA levels and various cancer types and stages. This study reinforces the utility of first void urine samples as a reliable proxy for blood-based liquid biopsy applications. Citation Format: Nafiseh Jafari, Jason Saenz, Lauren Lee, Carlos Hernandez, Andrew Dunnigan, Amit Arora, Rafal Iwasiow, Mayer Saidian. Urine as a non-invasive proxy for plasma in prostate cancer-related liquid biopsy applications [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 5042.

Abstract 4629: QClampTM Plex VEXAS syndrome UBA1 mutation detection assay: A noval XNA based assay to simultaneously detect eight UBA1 somatic mutations associated with VEXAS syndrome

Abstract VEXAS syndrome (acronym for Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) is a monogenic disease discovered in December 2020. It is an adult-onset systemic inflammatory disorder genetically characterized by somatic mutation of the UBA1 gene which encodes the ubiquitin like modifier activating enzyme 1. VEXAS patients have overlapping rheumatologic and hematologic manifestations, including increased risk for myelodysplastic syndrome (MDS). It is critically important to diagnose VEXAS syndrome, but UBA1 mutation test is still not commercially available. The three most frequent mutations of UBA1 gene are p.M41T(122T>C), p.M41V (c.121A>G), and p.M41L (c.121A>C) in codon 41 of exon 3. Other mutations including splice site mutations at exon 3 (c.118-2A>C, c.118-1G>C and c.118- 9_118-2del), p.S56F (c.167C>T) in codon 56 of exon 3, and p.S621C (c.1861A>T) in codon 621 of exon 16 have been reported. Based on XNA technology, we developed a QClampTM Plex platform to detect all the eight mutations in a single reaction with Luminex system. XNA technology enriches mutant target sequence in a PCR reaction by using synthetic DNA analog XNA (xenonucleic acid) to block wild type DNA. With spiking synthetic mutant DNA in GM24385 cell line DNA, we determined that this assay can detect mutations with a detection limit of variant allele frequency (VAF) for M41T at 0.1%, M41V at 0.1%, M41L at 0.25%, c.118-2A>C at 1%, c.118-1G>C at 1%, c.118- 9_118-2del at 1%, S56F at 0.25% and S621C at 1%, respectively, and specificity of 100% for all mutations. We tested saved DNA samples extracted from whole blood previously collected from suspected VEXAS patients and tested at the National Cancer Institute by Sanger sequencing, including 13 positive and 20 negative samples. Our assay detected all corresponding UBA1 mutations in the 13 positive patient samples, and did not detect UBA1 mutation in 18 of the 20 negative patient samples. Two of the 20 negative samples were also tested positive for UBA1 M41T and M41L on our assay, respectively, due to its significantly higher sensitivity than the Sanger sequencing platform, which has a detection limit of 15-20% VAF. Citation Format: Yunqing Ma. QClampTM Plex VEXAS syndrome UBA1 mutation detection assay: A noval XNA based assay to simultaneously detect eight UBA1 somatic mutations associated with VEXAS syndrome [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 4629.

It was not possible to detect BRAF V600E mutation in circulating cell-free DNA from patients with ameloblastoma: A diagnostic accuracy study.

The objective of this study is to evaluate the diagnostic accuracy of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA from patients with ameloblastoma. This is a prospective diagnostic accuracy study conducted based on the Standards for Reporting Diagnostic Accuracy recommendations. The index test was the plasma-based liquid biopsy, whereas the reference standard was the conventional tissue biopsy. The target condition was the detection of BRAF V600E mutation. The study population consisted of individuals with ameloblastoma recruited from three tertiary hospitals from Brazil. A negative control group composed of three individuals with confirmed wild-type BRAF lesions were included. The participants underwent plasma circulating cell-free DNA and tumor tissue DNA isolation, and both were submitted to using competitive allele-specific TaqMan™ real-time polymerase chain reaction technology mutation detection assays. Sensitivity and specificity measures and positive and negative predictive values were calculated. Twelve patients with conventional ameloblastoma were included. BRAF V600E mutation was detected in 11/12 (91.66%) ameloblastoma tissue samples. However, the mutation was not detected in any of the plasma-based liquid biopsy circulating cell-free DNA samples in both ameloblastomas and negative control group. The sensitivity and specificity of plasma-based liquid biopsy for the detection of the BRAF V600E mutation in circulating cell-free DNA was 0.0 and 1.0, respectively. The agreement between index test and reference standard results was 26.66%. Plasma-based liquid biopsy does not seem to be an accurate method for the detection of the BRAF V600E mutation in circulating circulating cell-free DNA from patients with ameloblastoma, regardless of tumor size, anatomic location, recurrence status, and other clinicopathological features.

A novel XNA-based Luminex assay to detect UBA1 somatic mutations associated with VEXAS syndrome

ObjectivesPatients with VEXAS syndrome carry mutations of UBA1 gene coding for the E1 enzyme. The three most frequent mutations are p.M41T(122T > C), p.M41V (c.121A > G), and p.M41L (c.121A > C) in codon 41 of exon 3. Currently, sanger sequencing was mainly used to detect these mutations, which has low sensitivity and low throughput. There is a need of high sensitivity, simple and high throughput method to characterize patients with VEXAS syndrome. MethodsBased on our proprietary XNA technology, we have developed a QClamp® Plex platform to detect eight mutations in a single reaction using the Luminex xMap technology. The assay sensitivity, specificity and precision were subsequently evaluated. Furthermore, the reference interval and clinical sensitivity/specificity were estimated using clinical healthy/positive DNA samples and the sanger sequencing method was used for comparison. ResultsWith spiking synthetic mutant DNA in wildtype GM24385 cell line DNA, this assay can detect UBA1 mutations with a detection limit of variant allele frequency (VAF) at 0.1–5%. Our assay shows 100% concordance with Sanger sequencing results when used for analyzing 15 positive and 19 negative clinical samples. ConclusionsThe QClamps® Plex UBA1 Mutation Detection Assay is a quicker, simpler, and more sensitive assay that can accurately detect the UBA1 mutations even at early stages with low mutation frequency.

Correlation analysis of risk factors for cervical lymphatic metastasis in papillary thyroid carcinoma

ObjectiveThis study aims to identify and analyze the risk factors associated with Cervical Lymph Node Metastasis (CNM) in Papillary Thyroid Carcinoma (PTC) patients.MethodsWe conducted a retrospective study involving the clinicopathological data of 2384 PTC patients admitted to our hospital between January 2016 and December 2020. All relevant data were statistically processed and analyzed.ResultsThe related risk factors for Central Lymph Node Metastasis (CLNM) were gender (male), age (≤ 30 years old), tumor lesion size (> 0.855 cm), and multifocal tumor foci. The ROC curve revealed that the critical value for predicting CLNM based on tumor lesion size was 0.855 (sensitivity = 57.9%, specificity = 69%, AUC = 0.269, and P < 0.05). Lateral Lymph Node Metastasis (LLNM) was positively correlated with tumor diameter. Specifically, the LLNM rate increased with the tumor diameter. LLNM occurrence was significantly higher in zones II, III, and IV than in zones I and V. Although the BRAF gene mutation detection assay has certain clinical benefits in diagnosing PTC and LLNM, no statistically significant difference was found in its relationship with central and lateral neck lymph node metastases (P = 0.741).ConclusionOur findings revealed that CLNM is associated with gender (male), age (≤ 30 years old), tumor lesion size (> 0.855 cm), and multiple tumor lesions in PTC patients. Central Lymph Node Dissection (CLND) is recommended for patients with these risk factors. On the other hand, preoperative ultrasound examination, fine-needle pathological examination, and genetic testing should be used to determine whether Lateral Cervical Lymph Node Dissection (LLND) is needed.

Colorimetric detection of single-nucleotide mutations based on rolling circle amplification and G-quadruplex-based DNAzyme.

In this work, we proposed a sensitive and selective colorimetric assay for single nucleotide mutation (SNM) detection combining rolling circle amplification (RCA) and G-quadruplex/hemin DNAzyme complex formation. In the detection principle, the first step involves ssDNA hybridization with a padlock probe (PLP) DNA, which can discriminate a single base mismatch. The successful ligation is followed by an RCA event to generate an abundance of G-quadruplexes (GQ-RCA) which are then transformed into a DNAzyme (G-quadruplex/hemin complex) by the addition of hemin. The color change from colorless 3,3',5,5'-tetramethylbenzidine (TMB) into colored oxTMB when hydrogen peroxide (H2O2) is added indicated the presence of a mutation. The assay had a limit of detection (LOD) of 2.14 pM. Mutations in samples from breast cancer patients were successfully detected with an accuracy of 100% when compared to Sanger sequencing results. The method is easily applicable even in resource poor setting regions given that it doesn't require any sophisticated or expensive instruments, and the signal readout is detectable simply by the naked eye. Our assay might be a useful tool for genetic analysis and clinical molecular diagnosis for breast cancer risk assessment and early detection.

Abstract A118: Somatic mutations in the PIK3CA gene and its prognostic implications among Ethiopian breast cancer patients

Abstract Purpose: The phosphatidylinositol-4, 5-bisphosphate 3-kinase (PIK3CA), catalytic subunit alpha (c) is frequently mutated in breast cancer (BC). Although the biological impact of PIK3CA mutations in BC has been studied in various parts of the world, limited data is available from sub-Saharan Africa. In this study, the frequency and the prognostic role of PIK3CA mutations were investigated among BC patients from Ethiopia. Methods: Formalin-fixed paraffin-embedded blocks and fresh frozen BC tissue samples were collected from patients newly diagnosed with BC. Histopathological evaluation was carried out using immunohistochemistry (IHC). PIK3CA mutation profiling was carried out using TaqMan® Mutation detection assay. The association between PIK3CA mutation status and clinical and histopathological features was evaluated. A survival regression (Cox’s model) was employed to assess the effect of PIK3CA mutation and other variables on survival. Results: The prevalence of the PIK3CA mutations was 20.4%. Mutation of the PIK3CA gene was mainly observed among younger (24%), early pT stage (19.4%), and G1/G2 tumors (22.3%). The proportion of mutation was 24.4%, 27.3% and 20% in ER+, PR+ and HER2- tumors, respectively. A marked difference was observed in the PIK3CA mutation frequency across the four major tumor subgroups. However, most of the mutated tumors were found among HR+/HER2− (24.1%) followed by HR+/HER2+ tumors (27.8%). In his study, only TNBC was negatively associated with the proportion of mutation in the PIK3CA gene (p-value= 0.02) in comparison to HR+/HER2- tumors. In multivariate Cox’s regression analysis, the advanced pT stage and HR−/HER2- IHC group independently predicted worse overall survival. However, PIK3CA mutation status was not associated with survival. Conclusions: The PIK3CA mutation was relatively high in HR+ tumors. Mutation rates of PIK3CA in Ethiopian BC tumors are similar to those reported for other populations. Citation Format: Zelalem Desalegn Woldesonbet, Meron Yohannes, Adamu Addissie, Tamrat Abebe, Eva Johanna Kantelhardt, Martina Vetter. Somatic mutations in the PIK3CA gene and its prognostic implications among Ethiopian breast cancer patients [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A118.

Abstract C074: Somatic mutations in the PIK3CA gene and its prognostic implications among Ethiopian breast cancer patients

Abstract Purpose: The phosphatidylinositol-4, 5-bisphosphate 3-kinase (PIK3CA), catalytic subunit alpha (c) is frequently mutated in breast cancer (BC). Although the biological impact of PIK3CA mutations in BC has been studied in various parts of the world, limited data is available from sub-Saharan Africa. In this study, the frequency and the prognostic role of PIK3CA mutations were investigated among BC patients from Ethiopia. Methods: Formalin-fixed paraffin-embedded blocks and fresh frozen BC tissue samples were collected from patients newly diagnosed with BC. Histopathological evaluation was carried out using immunohistochemistry (IHC). PIK3CA mutation profiling was carried out using TaqMan® Mutation detection assay. The association between PIK3CA mutation status and clinical and histopathological features was evaluated. A survival regression (Cox’s model) was employed to assess the effect of PIK3CA mutation and other variables on survival. Results: The prevalence of the PIK3CA mutations was 20.4%. Mutation of the PIK3CA gene was mainly observed among younger (24%), early pT stage (19.4%), and G1/G2 tumors (22.3%). The proportion of mutation was 24.4%, 27.3% and 20% in ER+, PR+ and HER2- tumors, respectively. A marked difference was observed in the PIK3CA mutation frequency across the four major tumor subgroups. However, most of the mutated tumors were found among HR+/HER2− (24.1%) followed by HR+/HER2+ tumors (27.8%). In his study, only TNBC was negatively associated with the proportion of mutation in the PIK3CA gene (p-value= 0.02) in comparison to HR+/HER2- tumors. In multivariate Cox’s regression analysis, the advanced pT stage and HR−/HER2- IHC group independently predicted worse overall survival. However, PIK3CA mutation status was not associated with survival. Conclusions: The PIK3CA mutation was relatively high in HR+ tumors. Such relatively higher molecular aberrations among HR+ tumors can provide a benefit in choosing the best therapeutic option for breast cancer. Citation Format: Zelalem Desalegn Woldesonbet, Meron Yohannes, Adamu Addissie, Tamrat Abebe, Eva Johanna Kantelhardt, Martina Vetter. Somatic mutations in the PIK3CA gene and its prognostic implications among Ethiopian breast cancer patients [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C074.