Multi-gene Targeting Research Articles

Anaplastic thyroid carcinoma: a genome-based search for new targeted therapy options

Abstract Introduction/Objective Anaplastic thyroid carcinoma (ATC) is a rare, aggressive thyroid cancer. Precision medicine, particularly gene-targeted therapy has emerged as a promising avenue in cancer treatment. However, few targeted therapies have been approved for ATC. Here, we present a genome-based search for new targeted therapy options using next-generation sequencing (NGS) data of 727 ATC cases. Methods/Case Report Deidentified NGS results in 727 ATC cases were obtained from Foundation Medicine. A search of the literature and genomic databases (TCGA, My Cancer Genome, and DGIdb) was performed to analyzed frequency of gene mutations and corresponding gene targeted drugs. Results (if a Case Study enter NA) Remarkably, 99.17% of the 727 ATC cases had at least one targeted drug option available. Among the 254 unique genes identified with pathogenic mutations, 150 (59.06%) were found to have at least 1 corresponding targeted drug. Among the top 35 most frequently mutated genes (frequency > 2.0%), 27 (80.00%) had available targeted therapies. Notably, most drug categories (70.83%) exhibited multi-gene targeting capabilities. The drug categories based on the percentage of genes targeted from highest to lowest are Serine/Threonine and Tryosine kinase inhibitors, therapeutic antibodies, MEK inhibitors, CDK inhibitors, AKT inhibitors, PI3K inhibitors and immunotherapies. There are an additional 16 drug categories that target 1 to 5 of the 35 frequently mutated genes identified. Of particular interest is MTAP, a previously unreported frequently mutated gene which is most often deleted (14.77%). Several drugs are undergoing phase 1 and/or phase 2 clinical trials for MTAP-deleted solid tumors. MTAP loss holds promise for identifying expanding therapeutic options in ATC. Conclusion Our genome-based analysis indicates that 99.17% of the 727 ATC cases have targeted drug options, targeting 59.06% of identified gene mutations. Among the 24 categories of targeted drugs 17 (70.83%) target more than one gene. The 2018 FDA approval of combination BRAF/MEK inhibitor therapy for management of BRAF V600E-positive ATC was a major first step in gene targeted therapies. Besides that, Tyrosine kinase inhibitors, mTOR inhibitor, PPAR-γ agonist, ALK inhibitor, VEGF inhibitor and several combined treatment and immunotherapeutic agents are currently being tested in ATC clinical trials. These promising findings highlight the expanding repertoire of gene-targeted therapy options in ATC and emphasizes the importance of combined strategies and identifying driver mutations.

A Novel AKT1, ERBB2, ESR1, KRAS, PIK3CA, and TP53 NGS Assay: A Non-Invasive Tool to Monitor Resistance Mechanisms to Hormonal Therapy and CDK4/6 Inhibitors.

Background: Patients with hormone receptor-positive (HR+)/HER2- metastatic breast cancer (mBC) generally receive hormonal therapy (HT) combined with CDK4/6 inhibitors (CDK4/6i). Despite this treatment, resistance mechanisms to CDK4/6i emerge and the majority of these patients experience disease progression (PD). This highlight the necessity to uncover the resistance mechanism to CDK4/6i through the identification of specific biomarkers. The primary objective is to assess the accuracy and feasibility of a novel multi-gene target panel NGS assay on circulating tumor DNA (ctDNA) to detect molecular alterations of AKT1, ERBB2, ESR1, KRAS, PIK3CA, and TP53 genes in women with BC undergoing HT plus CDK4/6i treatment. Secondarily, the study aims to explore the relationship between genomic profiling and clinical outcomes. Materials and Methods: Plasma samples were collected from 16 patients diagnosed with advanced/locally advanced HR+/HER2- BC at 2 time points: T0 (baseline) and at T1 (3 months after CDK4/6i treatment). Starting from 2 mL of plasma, ctDNA was isolated and libraries were set up using the Plasma-SeqSensei (PQS)® Breast Cancer IVD Kit, sequenced on Nextseq 550 and analyzed using the Plasma-SeqSensei™ IVD Software®. Results: Among the five patients who presented PD, three had PIK3CA mutations and, of these, two showed a higher mutant allele frequency (MAF) at T1. In three patients with stable disease and in eight patients with partial response, the MAF of the detected alterations decreased dramatically or disappeared during CDK4/6i treatment. Conclusions: Based on our findings, the liquid biopsy analysis using the PQS panel seems to be both feasible and accurate, demonstrating a strong sensitivity in detecting mutations. This exploratory analysis of the clinical outcome associated to the mutational status of patients highlights the potential of molecular analysis on liquid biopsy for disease monitoring, although further validation with a larger patient cohort is necessary to confirm these preliminary observations.

Marker recycling in Lentinula edodes via 5-fluoroorotic acid counter-selection.

Shiitake (Lentinula edodes) contains various beneficial compounds and possesses several notable properties. However, there are few reports on its molecular breeding due to delay in development of its gene-modifying technology. Therefore, here, strain UV30 (pyrG -) was bred from the UV-irradiated protoplasts of strain M2. Strain UV30 was uracil-auxotrophic, and the phenylalanine residue in the active centre of orotidine-5-phosphate decarboxylase encoded by pyrG in the strain was substituted with a serine residue. Next, a recycling marker consisting of the upstream sequence of ku80, a repeat sequence (a portion of the downstream sequence of ku80), pyrG, and the downstream sequence of ku80 was introduced into the strain UV30. Consequently, the prototrophic strain ckp2-1, in which ku80 was replaced with the recycling marker, was obtained. After cultivation in complete medium, mycelia from the edges of ckp2-1 colonies were inoculated into a complete medium containing 5-Fluoroorotic acid (5-FOA). A 5-FOA-resistant strain KaM2, in which pyrG sequence was spliced from the recycling marker sequence via homologous recombination, was obtained. In this study, we developed the first marker recycling system for multigene targeting in L. edodes. Moreover, the resulting ∆ku80 strain may serve as a non-homologous end-joining deficient strain for further genetic manipulations.

Versatile Cloning Strategy for Efficient Multigene Editing in Arabidopsis.

CRISPR-Cas9 technology has become an essential tool for plant genome editing. Recent advancements have significantly improved the ability to target multiple genes simultaneously within the same genetic background through various strategies. Additionally, there has been significant progress in developing methods for inducible or tissue-specific editing. These advancements offer numerous possibilities for tailored genome modifications. Building upon existing research, we have developed an optimized and modular strategy allowing the targeting of several genes simultaneously in combination with the synchronized expression of the Cas9 endonuclease in the egg cell. This system allows significant editing efficiency while avoiding mosaicism. In addition, the versatile system we propose allows adaptation to inducible and/or tissue-specific edition according to the promoter chosen to drive the expression of the Cas9 gene. Here, we describe a step-by-step protocol for generating the binary vector necessary for establishing Arabidopsis edited lines using a versatile cloning strategy that combines Gateway® and Golden Gate technologies. We describe a versatile system that allows the cloning of as many guides as needed to target DNA, which can be multiplexed into a polycistronic gene and combined in the same construct with sequences for the expression of the Cas9 endonuclease. The expression of Cas9 is controlled by selecting from among a collection of promoters, including constitutive, inducible, ubiquitous, or tissue-specific promoters. Only one vector containing the polycistronic gene (tRNA-sgRNA) needs to be constructed. For that, sgRNA (composed of protospacers chosen to target the gene of interest and sgRNA scaffold) is cloned in tandem with the pre-tRNA sequence. Then, a single recombination reaction is required to assemble the promoter, the zCas9 coding sequence, and the tRNA-gRNA polycistronic gene. Each element is cloned in an entry vector and finally assembled according to the Multisite Gateway® Technology. Here, we detail the process to express zCas9 under the control of egg cell promoter fused to enhancer sequence (EC1.2en-EC1.1p) and to simultaneously target two multiple C2 domains and transmembrane region protein genes (MCTP3 and MCTP4, respectively at3g57880 and at1g51570), using one or two sgRNA per gene. Key features • A simple method for Arabidopsis edited lines establishment using CRISPR-Cas9 technology • Versatile cloning strategy combining various technologies for convenient cloning (Gateway®, Golden Gate) • Multigene targeting with high efficiency.

Telomere integrated scoring system of myelodysplastic syndrome.

Recently, multigene target sequencing is widely performed for the purpose of prognostic prediction and application of targeted therapy. Here, we proposed a new scoring system that encompasses gene variations, telomere length, and Revised International Prognostic Scoring System (IPSS-R) together in Asian myelodysplastic syndrome. We developed a new scoring model of these variables: age≥ 65 years + IPSS-R score + ASXL1 mutation + TP53 mutation + Telomere length (<5.37). According to this new scoring system, patients were divided into four groups: very good score cutoff (≤3.0), good (3.0-4.5), poor (4.5-7.0), and very poor (>7.0). The median OS was 170.1, 100.4, 46.0, and 12.0months for very good, good, poor, and very poor, retrospectively (p < 0.001). Meanwhile, according to the conventional IPSS-R scoring system, the median OS was 141.3, 50.2, 93.0, 36.0, and 16.2months for very low, low, intermediate, high, and very high, retrospectively (p < 0.001). The newly developed model incorporating molecular variations and TL yielded more clear separations of the survival curves. By adding the presence of gene mutation and telomere length to the existing IPSS-R, its predictive ability can be further improved in myelodysplastic syndrome.

Development and Clinical Validation of RT-LAMP-Based Lateral-Flow Devices and Electrochemical Sensor for Detecting Multigene Targets in SARS-CoV-2.

Consistently emerging variants and the life-threatening consequences of SARS-CoV-2 have prompted worldwide concern about human health, necessitating rapid and accurate point-of-care diagnostics to limit the spread of COVID-19. Still, However, the availability of such diagnostics for COVID-19 remains a major rate-limiting factor in containing the outbreaks. Apart from the conventional reverse transcription polymerase chain reaction, loop-mediated isothermal amplification-based (LAMP) assays have emerged as rapid and efficient systems to detect COVID-19. The present study aims to develop RT-LAMP-based assay system for detecting multiple targets in N, ORF1ab, E, and S genes of the SARS-CoV-2 genome, where the end-products were quantified using spectrophotometry, paper-based lateral-flow devices, and electrochemical sensors. The spectrophotometric method shows a LOD of 10 agµL-1 for N, ORF1ab, E genes and 100 agµL-1 for S gene in SARS-CoV-2. The developed lateral-flow devices showed an LOD of 10 agµL-1 for all four gene targets in SARS-CoV-2. An electrochemical sensor developed for N-gene showed an LOD and E-strip sensitivity of log 1.79 ± 0.427 pgµL-1 and log 0.067 µA/pg µL-1/mm2, respectively. The developed assay systems were validated with the clinical samples from COVID-19 outbreaks in 2020 and 2021. This multigene target approach can effectively detect emerging COVID-19 variants using combination of various analytical techniques at testing facilities and in point-of-care settings.

Clinical and Genomic Profiles of Korean Patients with MECOM Rearrangement and the t(3;21)(q26.2;q22.1) Translocation.

The translocation (3;21)(q26.2;q22.1) is a unique cytogenetic aberration that characterizes acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) in patients with AML and myelodysplastic syndrome (MDS) or a therapy-related myeloid neoplasm. Using multigene target sequencing and FISH, we investigated the clinical and genomic profiles of patients with t(3;21) over the past 10 years. The frequency of t(3;21) among myeloid malignancies was very low (0.2%). Half of the patients had a history of cancer treatment and the remaining patients had de novo MDS. Twenty-one somatic variants were detected in patients with t(3;21), including in CBL, GATA2, and SF3B1. Recurrent variants in RUNX1 (c.1184A>C, p.Glu395Ala) at the same site were detected in two patients. None of the patients with t(3;21) harbored germline predisposition mutations for myeloid neoplasms. MECOM rearrangement was detected at a higher rate using FISH than using G-banding, suggesting that FISH is preferable for monitoring. Although survival of patients with t(3;21) is reportedly poor, the survival of patients with t(3;21) in this study was not poor when compared with that of other AML patients in Korea.

54P Assessment of EU4 laboratory readiness for FGFR2 fusion testing of cholangiocarcinoma by NGS

ESMO recently published Next Generation Sequencing (NGS) testing recommendations for solid tumors, which includes cholangiocarcinoma (CCA), for use of small or large multigene target NGS panels to identify actionable variants. The European Medicines Agency has approved an FGFR2 inhibitor for advanced, metastatic CCA FGFR2 fusion positive patients. With more FGFR2 therapies anticipated, it will be important to identify all CCA patients with any FGFR2 fusion.

CRISPR-Based Genome Editing Tools: Insights into Technological Breakthroughs and Future Challenges.

Genome-editing (GE) is having a tremendous influence around the globe in the life science community. Among its versatile uses, the desired modifications of genes, and more importantly the transgene (DNA)-free approach to develop genetically modified organism (GMO), are of special interest. The recent and rapid developments in genome-editing technology have given rise to hopes to achieve global food security in a sustainable manner. We here discuss recent developments in CRISPR-based genome-editing tools for crop improvement concerning adaptation, opportunities, and challenges. Some of the notable advances highlighted here include the development of transgene (DNA)-free genome plants, the availability of compatible nucleases, and the development of safe and effective CRISPR delivery vehicles for plant genome editing, multi-gene targeting and complex genome editing, base editing and prime editing to achieve more complex genetic engineering. Additionally, new avenues that facilitate fine-tuning plant gene regulation have also been addressed. In spite of the tremendous potential of CRISPR and other gene editing tools, major challenges remain. Some of the challenges are related to the practical advances required for the efficient delivery of CRISPR reagents and for precision genome editing, while others come from government policies and public acceptance. This review will therefore be helpful to gain insights into technological advances, its applications, and future challenges for crop improvement.

Role of somatic mutations and chromosomal aberrations in the prognosis of uveal melanoma in a Spanish patient cohort.

Uveal melanoma (UM) has a high tendency to cause liver metastases. Metastatic disease is fatal, with a low survival rate. There are two large groups of UMs that, according to their risk of metastatic disease, can be divided into risk subgroups based on histopathological, cytogenetic and molecular characteristics. The presence of somatic mutations in certain genes may explain the origin and prognosis of these tumours. Forty-six UM samples previously classified as high or low metastatic risk according to chromosome 3 copy number status were tested for somatic mutations. A multi-gene targeting strategy was adopted, and sequencing was performed using AmpliSeq technology. Mutations were found in all major UM-related genes. BAP1 mutations confer an increased risk of metastases in high-risk tumours; thus, this gene acts as a strong prognostic predictor in UM. The presence of somatic mutations in LZTS1 did not show significant differences in the risk of metastases. This result supports the idea that exploring mutations and copy number variations in UM provides insights into patient outcomes. Genetic tests allow the determination of accurate personalized molecular profiles with a fundamental prognostic purpose.

CRISPR/Cas9 Genome Editing Technology: A Valuable Tool for Understanding Plant Cell Wall Biosynthesis and Function.

For the past 5 years, clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology has appeared in the molecular biology research spotlight. As a game-changing player in genome editing, CRISPR/Cas9 technology has revolutionized animal research, including medical research and human gene therapy as well as plant science research, particularly for crop improvement. One of the most common applications of CRISPR/Cas9 is to generate genetic knock-out mutants. Recently, several multiplex genome editing approaches utilizing CRISPR/Cas9 were developed and applied in various aspects of plant research. Here we summarize these approaches as they relate to plants, particularly with respect to understanding the biosynthesis and function of the plant cell wall. The plant cell wall is a polysaccharide-rich cell structure that is vital to plant cell formation, growth, and development. Humans are heavily dependent on the byproducts of the plant cell wall such as shelter, food, clothes, and fuel. Genes involved in the assembly of the plant cell wall are often highly redundant. To identify these redundant genes, higher-order knock-out mutants need to be generated, which is conventionally done by genetic crossing. Compared with genetic crossing, CRISPR/Cas9 multi-gene targeting can greatly shorten the process of higher-order mutant generation and screening, which is especially useful to characterize cell wall related genes in plant species that require longer growth time. Moreover, CRISPR/Cas9 makes it possible to knock out genes when null T-DNA mutants are not available or are genetically linked. Because of these advantages, CRISPR/Cas9 is becoming an ideal and indispensable tool to perform functional studies in plant cell wall research. In this review, we provide perspectives on how to design CRISPR/Cas9 to achieve efficient gene editing and multi-gene targeting in plants. We also discuss the recent development of the virus-based CRISPR/Cas9 system and the application of CRISPR/Cas9 to knock in genes. Lastly, we summarized current progress on using CRISPR/Cas9 for the characterization of plant cell wall-related genes.

Development of a system for efficient callus production, somatic embryogenesis and gene editing using CRISPR/Cas9 in Saffron (Crocus sativus L.)

BackgroundCrocus sativus is a recalcitrant plant for genetic transformation and genetic improvement, largely due to difficulties in Agrobacterium mediated transformation and vegetative reproduction. Effective genome editing requires proficient callus production and an efficient method to deliver Cas9 and sgRNAs into the plant. Here, we demonstrate Agrobacterium-mediated transformation of saffron. Further, we developed a CRISPR-Cas9 based system in this plant, for efficient gene knockout or edits in future.ResultsEfficient callus production and regeneration confers important benefits in developing competent transformation system in plants. More than 70% multiplication rate of callus initiation was achieved from corm slices of saffron subjected to a two-step sterilization procedure and grown on complete MS medium supplemented with 2,4-D (0.5 mg/L), BAP (1 mg/L), IAA (1 mg/L), photoperiod of 16/8 h and 45% relative humidity at 20 ± 2 °C. In vitro cormlet generation was accomplished in 8 weeks by using mature somatic embryos on MS medium supplemented with TDZ (0.5 mg/L) + IAA (1 mg/L) + Activated charcoal (0.1 g/L) at 15 ± 2 °C. The attempt of using Agrobacterium-mediated transformation resulted in successful integration of the binary vector into the somatic embryos of saffron with a transformation efficiency of 4%. PCR and Southern blot analysis confirmed the integration of Cas9 into saffron.ConclusionThe protocol for callus production, somatic embryogenesis and regeneration was standardised. Successful demonstration of integrated Cas9 in this study constitutes first step in developing strategies for genetic manipulation of saffron, which has so far been considered recalcitrant. Furthering the development of this technology holds significant potential for advancing genetic research in saffron by integrating multigene targeting and/or use of recyclable cassettes.

Mutation analysis in Korean patients with T-cell acute lymphoblastic leukemia

Genomic studies have illuminated the alterations in pathways underlying T-cell acute lymphoblastic leukemia (T-ALL) pathogenesis, but detailed mutation data by next-generation sequencing have not been reported in Korean patients. We aimed to investigate mutation frequency, spectrum, and pattern in the Korean patients with T-ALL. We designed a multigene panel targeting 101 genes and validated it using 10 reference materials. The mutation analysis was done in a total of 10 patients with T-ALL. Clinical data and laboratory tests including immunophenotyping, cytogenetics, and molecular genetic tests were also investigated. All of the 10 patients harbored at least one mutation (range 1–6 per patient). A total of 34 clinically significant mutations including 15 novel mutations were identified in 23 genes. The median of variant allelic frequencies (VAFs) and blasts were counted upto 33% (range 5–91%) and 79% (range 38–90%), respectively. Recurrent mutations were involved in epigenetic regulators (60%), NOTCH1 signaling (40%), PI3K-AKT (40%), JAK-STAT (30%), and transcription factors (30%). We found that both NOTCH signaling and JAK-STAT signaling were positively associated with epigenetic regulators, while showed mutually exclusive patterns with PI3K-AKT pathway. This study showed that the frequency of mutations in epigenetic regulators in Korean patients was significantly higher than expected. Distribution of VAF as well as mutation spectrum is considerably heterogeneous in Korean patients with T-ALL. Although from a limited number of patients, this study provides the first detailed mutational portrait of T-ALL of Korean patients, and gives additional insight into molecular pathogenesis of the disease.

Tripodal RNA with 3' Overhangs Prevents RIG-I-Mediated Innate Immune Response.

RNA interference (RNAi) offers great promise in life science research and therapeutic development, as it easily achieves a potent target gene knockdown with high specificity. Since the conventional small interfering RNA (siRNA) structure, known as 19 bp double-stranded RNA (dsRNA) with 2-nucleotide (nt) 3' overhang, has been introduced to successfully elicit the RNAi in mammalian cells, a variety of structural variants of RNAi trigger have been developed. Our group previously reported branched, tripodal interfering RNA (tiRNA) structures as a multigene targeting RNA structure inducing RNAi. However, the immune stimulatory effect of branched tiRNA structure has not been thoroughly evaluated. In this study, we show that tiRNA with blunt ends triggers innate immune response in T98G cell and mouse macrophage cells, which is dependent upon the retinoic acid-inducible gene I (RIG-I), a well-known cytoplasmic dsRNA sensor. Interestingly, immune response triggered by tiRNA can be suppressed by the introduction of 2-nt 3' overhang structure. Our finding expands the structural diversity of RIG-I ligands and provides a guide to develop a safe multitargeting RNA structure for therapeutic application.

Molecular diagnosis of hereditary spherocytosis by multi-gene target sequencing in Korea: matching with osmotic fragility test and presence of spherocyte

BackgroundCurrent diagnostic tests for hereditary spherocytosis (HS) focus on the detection of hemolysis or indirectly assessing defects of membrane protein, whereas direct methods to detect protein defects are complicated and difficult to implement. In the present study, we investigated the patterns of genetic variation associated with HS among patients clinically diagnosed with HS.MethodsMulti-gene targeted sequencing of 43 genes (17 RBC membrane protein-encoding genes, 20 RBC enzyme-encoding genes, and six additional genes for the differential diagnosis) was performed using the Illumina HiSeq platform.ResultsAmong 59 patients with HS, 50 (84.7%) had one or more significant variants in a RBC membrane protein-encoding genes. A total of 54 significant variants including 46 novel mutations were detected in six RBC membrane protein-encoding genes, with the highest number of variants found in SPTB (n = 28), and followed by ANK1 (n = 19), SLC4A1 (n = 3), SPTA1 (n = 2), EPB41 (n = 1), and EPB42 (n = 1). Concurrent mutations of genes encoding RBC enzymes (ALDOB, GAPDH, and GSR) were detected in three patients. UGT1A1 mutations were present in 24 patients (40.7%). Positive rate of osmotic fragility test was 86.8% among patients harboring HS-related gene mutations.ConclusionsThis constitutes the first large-scaled genetic study of Korean patients with HS. We demonstrated that multi-gene target sequencing is sensitive and feasible that can be used as a powerful tool for diagnosing HS. Considering the discrepancies of clinical and molecular diagnoses of HS, our findings suggest that molecular genetic analysis is required for accurate diagnosis of HS.

Nanoscale polyelectrolyte complexes encapsulating mRNA and long-chained siRNA for combinatorial cancer gene therapy

To precisely regulate target genes that are abnormally expressed in cancers, we suggest an RNA-mediated multigene targeting system that co-encapsulates siRNA against vascular endothelial growth factor (VEGF) and mRNA encoding phosphatase and tensin homolog (PTEN). Polymerized long-chain siRNAs (L-siRNAs) formed stable and condensed nanocomplexes with mRNAs using thiolated glycol chitosans (tGCs) as gene carriers. The mRNA/L-siRNA/tGC nanocomplexes (MSNs) exhibited efficient intracellular delivery and superior anti-tumor efficiency with simultaneous up and down-regulation of PTEN and VEGF, respectively. The MSN system can be considered as a new platform for cancer gene therapy requiring accurate control of multiple gene expressions.

Elucidating Waterborne Pathogen Presence and Aiding Source Apportionment in an Impaired Stream.

Fecal indicator bacteria (FIB) are the basis for water quality regulations and are considered proxies for waterborne pathogens when conducting human health risk assessments. The direct detection of pathogens in water and simultaneous identification of the source of fecal contamination are possible with microarrays, circumventing the drawbacks to FIB approaches. A multigene target microarray was used to assess the prevalence of waterborne pathogens in a fecally impaired mixed-use watershed. The results indicate that fecal coliforms have improved substantially in the watershed since its listing as a 303(d) impaired stream in 2002 and are now near United States recreational water criterion standards. However, waterborne pathogens are still prevalent in the watershed, as viruses (bocavirus, hepatitis E and A viruses, norovirus, and enterovirus G), bacteria (Campylobacter spp., Clostridium spp., enterohemorrhagic and enterotoxigenic Escherichia coli, uropathogenic E. coli, Enterococcus faecalis, Helicobacter spp., Salmonella spp., and Vibrio spp.), and eukaryotes (Acanthamoeba spp., Entamoeba histolytica, and Naegleria fowleri) were detected. A comparison of the stream microbial ecology with that of sewage, cattle, and swine fecal samples revealed that human sources of fecal contamination dominate in the watershed. The methodology presented is applicable to a wide range of impaired streams for the identification of human health risk due to waterborne pathogens and for the identification of areas for remediation efforts.IMPORTANCE The direct detection of waterborne pathogens in water overcomes many of the limitations of the fecal indicator paradigm. Furthermore, the identification of the source of fecal impairment aids in identifying areas for remediation efforts. Multitarget gene microarrays are shown to simultaneously identify waterborne pathogens and aid in determining the sources of impairment, enabling further focused investigations. This study shows the use of this methodology in a historically impaired watershed in which total maximum daily load reductions have been successfully implemented to reduce risk. The results suggest that while the fecal indicators have been reduced more than 96% and are nearing recreational water criterion levels, pathogens are still detectable in the watershed. Microbial source tracking results show that additional remediation efforts are needed to reduce the impact of human sewage in the watershed.

Comparison of Clinical Diagnosis for Hereditary Spherocytosis with Molecular Diagnosis By Multi-Gene Target Sequencing in Korea

Background: Hereditary spherocytosis (HS) is the most common cause of hereditary hemolytic anemia. Current tests used to diagnose HS focus on the detection of hemolysis or indirectly assess protein defects. Direct methods to detect protein defects are complicated and difficult to implement. Recent next-generation sequencing (NGS) methods enable large-scale gene mutation analyses to be used for such diagnoses. In this study, we investigated the patterns of genetic variation associated with HS among the patients diagnosed with HS clinically. Specifically, we analyzed mutations in red blood cell membrane protein-encoding genes (17 genes) in context with 5 genes for the differential diagnosis (thalassemia, congenital dyserythropoietic anemia, paroxysmal nocturnal hemoglobinuria) in Korean HS.Methods: In total, 60 patients diagnosed with HS were enrolled in this study. Targeted sequencing of 43 genes (17 membrane protein-encoding genes, 20 enzyme-encoding genes, and 6 additional candidate genes) was performed using the Illumina HiSeq platform and variants were called according to a data-processing pipeline.Results: Of the 60 patients, 50 (83%) had one or more significant variants in a membrane protein encoding genes. A total of 54 significant variants (8 previously reported and 46 novel) were detected in 6 membrane protein-encoding genes; SPTB, ANK1, SPTA1, SLC4A1, EPB41, and EPB42. The most variants (28/60 patients) were detected in SPTB. Interestingly, concurrent mutations of genes encoding enzymes (ALDOB, GAPDH, and GSR) were detected along with mutations of membrane encoding genes. One patient diagnosed with HS harbored mutation of G6PD without mutation of HS related genes. Additionally, UGT1A1 mutations were present in 5 patients. Positive rate of osmotic fragility test was 86% among patients with HS related gene mutations.Conclusion: These results clarify the molecular genetic analysis is required for the accurate diagnosis of HS. About 17% of patients who were clinically diagnosed as HS revealed discrepancy with molecular diagnosis. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Abstract 3171: Powerful target capture/NGS approach reveals extensive genetic changes including SNVs, CNVs and gross chromosomal rearrangements in colorectal cancers

Abstract Introduction: Accurate and comprehensive molecular analyses of genetic changes in cancer tissues are critical for cancer management, treatment, and genetic counseling. Study of the complete molecular profiles in patient's blood, cacinoma tissue and surrounding pathological normal tissues will help us understand the etiology of colorectal cancers (CRC) as either hereditary or sporadic. In addition, this study will also reveal somatic changes and possible targets for therapy. Multigene target capture followed by deep next generation sequencing (NGS) provides a powerful approach to simultaneously detect both single nucleotide variants (SNVs) and exonic copy number variants (CNVs) in a time and cost effective fashion. Method: DNA samples were prepared from blood, freshly frozen normal surrounding and carcinoma or polyp tissues from 20 patients with CRC and 10 patients with colorectal polyps. A custom probe library containing 183 cancer related genes was used to capture the target sequences followed by NGS with deep coverage (average depth per base is ∼1000X). Both SNVs and CNVs were analyzed based on in-house developed analytical algorithm and bioinformatics pipeline. Results: This study revealed extensive genetic changes in colon carcinoma tissues. At least 40% of the colon carcinoma samples harbor loss-of-function pathogenic germline mutations in cancer related genes. However, loss of function germline mutations were not found in the polyps. Germline missense variants of unknown significance were identified in 60% of the polyps. Multiple deleterious somatic mutations are identified in all carcinoma tissues but only 1-2 somatic mutations per sample are found in the polyps. Almost every carcinoma tissue harbor gross chromosomal rearrangement, which is only found in about 50% of the polyp tissues.. NGS based CNV analysis revealed 2 germline events (FANCD2 E15-16 del; whole ALK gene dup). Somatic CNV events are more frequently observed in carcinoma tissues. Gross changes at chromosomal levels were also detected by using the NGS CNV analytical algorithm. Recurrent somatic pathogenic variants in genes associated with CRC, such as APC, TP53, and KRAS were identified while novel likely pathogenic variants in novel genes possibly linked to CRC were also discovered for further investigation. Heterogeneity of carcinoma tissues within the same individual was suggested by comparing allele frequency of different somatic mutations. Numerous loss of heterozygosity was observed in both carcinoma and polyp tissues. Conclusion: Target capture/NGS approach allows simultaneous analyses of SNVs and CNVs with quantitative data to distinguish between germline and somatic mutations. These analyses reveal abundant and valuable molecular information for target therapy, patient management, genetic counseling, and new insights of possible pathogenic mechanism Citation Format: Hongzheng Dai, Xia Tian, Stella Chen, Yue Wang, Tzu-Wei Yang, Chun-Che Lin, Ming-Chang Tsai, Chih-Hong Wang, Chi-Chou Huang, Chin-Ying Shih, Guang-Yuh Chiou, Yuh-Jyh Jong, Lee-Jun Wong. Powerful target capture/NGS approach reveals extensive genetic changes including SNVs, CNVs and gross chromosomal rearrangements in colorectal cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3171.

Molecular Diagnosis of Hereditary Spherocytosis By Multi-Gene Target Sequencing in Korea

Background: Hereditary spherocytosis (HS) is the most common cause of hereditary hemolytic anemia. Spherocytes formed by defective membrane proteins are selectively captured in the spleen and destroyed, leading to hemolytic anemia. Current tests used to diagnose HS focus on the detection of hemolysis or indirectly assess protein defects. Direct methods to detect protein defects are complicated and difficult to implement. Recent next-generation sequencing (NGS) methods enable large-scale gene mutation analyses to be used for such diagnoses. In this study, we investigated the patterns of genetic variation associated with HS to determine the molecular mechanisms underlying the condition. Specifically, we analyzed mutations in red blood cell membrane protein-encoding genes in Korean HS patients using NGS.Methods: In total, 60 patients with HS were enrolled in this study. Targeted sequencing of 43 genes (17 membrane protein-encoding genes, 20 enzyme-encoding genes, and 6 additional candidate genes) was performed using the Illumina HiSeq platform and variants were called according to a data-processing pipeline.Results: Of the 60 patients, 50 (83%) had one or more significant variants in a membrane protein gene. A total of 54 significant variants (8 previously reported and 46 novel) were detected in 6 membrane protein-encoding genes, i.e., SPTB, ANK1, SPTA1, SLC4A1, EPB41, and EPB42. The most variants (28) were detected in SPTB. Four significant variants, all of which were previously reported, were detected in genes encoding enzymes (ALDOB, G6PD, GAPDH, and GSR). Additionally, 5 previously reported variants were detected in UGT1A1. These results suggest 35 primer sets that can be used to diagnose HS.Conclusion: This was the first large-scaled genetic study of Korean HS patients. These results clarify the pattern of genetic variation associated with HS in Korean patients. They will enable easier, more rapid diagnosis of HS. DisclosuresNo relevant conflicts of interest to declare.