Microsatellite instability detection using a large next-generation sequencing cancer panel across diverse tumour types

2019 ◽  
Vol 73 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Jiuhong Pang ◽  
Tatyana Gindin ◽  
Mahesh Mansukhani ◽  
Helen Fernandes ◽  
Susan Hsiao
Keyword(s):  
Next Generation Sequencing ◽  
Microsatellite Instability ◽  
Microsatellite Loci ◽  
Clinical Samples ◽  
Next Generation ◽  
Diverse Range ◽  
Tree Classifier ◽  
Generation Sequencing ◽  
Cancer Panel ◽  
Clinical Cases

AimMicrosatellite instability (MSI), a hallmark of DNA mismatch repair deficiency, is a key molecular biomarker with multiple clinical implications including the selection of patients for immunotherapy, identifying patients who may have Lynch syndrome and predicting prognosis in patients with colorectal tumours. Next-generation sequencing (NGS) provides the opportunity to interrogate large numbers of microsatellite loci concurrently with genomic variants. We sought to develop a method to detect MSI that would not require paired normal tissue and would leverage the sequence data obtained from a broad range of tumours tested using our 467-gene NGS Columbia Combined Cancer Panel (CCCP).MethodsAltered mononucleotide and dinucleotide microsatellite loci across the CCCP region of interest were evaluated in clinical samples encompassing a diverse range of tumour types. The number of altered loci was used to develop a decision tree classifier model trained on the retrospectively collected cohort of 107 clinical cases sequenced by the CCCP assay.ResultsThe classifier was able to correctly classify all cases and was then used to analyse a test set of clinical cases (n=112) and was able to correctly predict their MSI status with 100% sensitivity and specificity. Analysis of recurrently altered loci identified alterations in genes involved in DNA repair, signalling and transcriptional regulation pathways, many of which have been implicated in MSI tumours.ConclusionThis study highlights the utility of this approach, which should be applicable to laboratories performing similar testing.

scholarly journals MiMSI - a deep multiple instance learning framework improves microsatellite instability detection from tumor next-generation sequencing

2020 ◽  
Author(s):  
John Ziegler ◽  
Jaclyn F. Hechtman ◽  
Ryan Ptashkin ◽  
Gowtham Jayakumaran ◽  
Sumit Middha ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Microsatellite Instability ◽  
Checkpoint Inhibitors ◽  
Multiple Instance Learning ◽  
Next Generation Sequencing Data ◽  
Clinical Samples ◽  
Next Generation ◽  
Learning Framework ◽  
Tumor Purity ◽  
Generation Sequencing

AbstractMicrosatellite instability (MSI) is a critical phenotype of cancer genomes and an FDA-recognized biomarker that can guide treatment with immune checkpoint inhibitors. Recent work has demonstrated that next-generation sequencing data can be used to identify samples with MSI-high phenotype. However, low tumor purity, as frequently observed in routine clinical samples, poses a challenge to the sensitivity of existing algorithms. To overcome this critical issue, we developed MiMSI, an MSI classifier based on deep neural networks and trained using a dataset that included low tumor purity MSI cases in a multiple instance learning framework. On a challenging yet representative set of cases, MiMSI showed higher sensitivity (0.940) and auROC (0.988) than MSISensor(sensitivity: 0.57; auROC: 0.911), an open-source software previously validated for clinical use at our institution using MSK-IMPACT large panel targeted NGS data.

A Novel Method for Microsatellite Instability Detection by Liquid Biopsy Based on Next- Generation Sequencing

2020 ◽  
Vol 15 ◽  
Author(s):  
Zheng Jiang ◽  
Hui Liu ◽  
Siwen Zhang ◽  
Jia Liu ◽  
Weitao Wang ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Microsatellite Instability ◽  
Liquid Biopsy ◽  
Tumor Tissue ◽  
High Sensitivity ◽  
Next Generation ◽  
Tissue Samples ◽  
Next Generation Sequencing Technology ◽  
Medication Selection ◽  
Generation Sequencing

Background: Microsatellite instability (MSI) is a prognostic biomarker used to guide medication selection in multiple cancers, such as colorectal cancer. Traditional PCR with capillary electrophoresis and next-generation sequencing using paired tumor tissue and leukocyte samples are the main approaches for MSI detection due to their high sensitivity and specificity. Currently, patient tissue samples are obtained through puncture or surgery, which causes injury and risk of concurrent disease, further illustrating the need for MSI detection by liquid biopsy. Methods: We propose an analytic method using paired plasma/leukocyte samples and MSI detection using next-generation sequencing technology. Based on the theoretical progress of oncogenesis, we hypothesized that the microsatellite site length in plasma equals the combination of the distribution of tumor tissue and leukocytes. Thus, we defined a window-judgement method to identify whether biomarkers were stable. Results: Compared to traditional PCR as the standard, we evaluated three methods in 20 samples (MSI-H:3/MSS:17): peak shifting method using tissue vs. leukocytes, peak shifting method using plasma vs. leukocytes, and our method using plasma vs. leukocytes. Compared to traditional PCR, we observed a sensitivity of 100%, 0%, and 100%, and a specificity of 100.00%, 94.12%, and 88.24%, respectively. Conclusion: Our method has the advantage of possibly detecting MSI in a liquid biopsy and provides a novel direction for future studies to increase the specificity of the method.

MICROBIOMA: AMIGO O ENEMIGO EN PACIENTES CON COVID - 19

SCIENTIARVM ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 15-21
Author(s):  
Katherine Milagros Quispe Medina ◽  
◽  
Angel Sixto Mamani Ruelas ◽  
Brenda Jasmin Alvarez Vera ◽  
Yasmin Yessenia Silvestre Gutierrez ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Gastrointestinal Tract ◽  
Molecular Biology ◽  
Gut Microbiome ◽  
Next Generation ◽  
Multiple Factors ◽  
Lung Microbiome ◽  
The Relationship ◽  
Generation Sequencing ◽  
Clinical Cases

The research of the microbiome concerning various diseases has grown in the last ten years due to the advances in molecular biology and next-generation sequencing, finding interactions with various pathologies. The new coronavirus 19 (SARS-COV 2) pandemic has aroused interest in the study of multiple factors that could influence in the development of symptoms mainly due to the interaction of the microbiome whether of the respiratory or gastrointestinal tract finally in the prognosis. Therefore, in this study, we focus on reviewing and analyzing the current bibliography of research and clinical cases about the relationship between the lung and gut microbiome and COVID-19, highlighting its effect on infected patients, aiming to contribute to this new line of research. Keywords: Microbiome, COVID-19, SARS-COV 2, gut microbiome, lung microbiome.

scholarly journals Next-Generation Sequencing Approach to Non–Small Cell Lung Carcinoma Yields More Actionable Alterations

2017 ◽  
Vol 142 (3) ◽  
pp. 353-357 ◽  
Author(s):  
Mitra Mehrad ◽  
Somak Roy ◽  
Humberto Trejo Bittar ◽  
Sanja Dacic
Keyword(s):  
Next Generation Sequencing ◽  
Lung Adenocarcinoma ◽  
Small Cell ◽  
Gene Panel ◽  
Next Generation ◽  
Small Cell Lung ◽  
Genomic Alterations ◽  
Generation Sequencing ◽  
Gene Alterations ◽  
Cancer Panel

Context.— Different testing algorithms and platforms for EGFR mutations and ALK rearrangements in advanced-stage lung adenocarcinoma exist. The multistep approach with single-gene assays has been challenged by more efficient next-generation sequencing (NGS) of a large number of gene alterations. The main criticism of the NGS approach is the detection of genomic alterations of uncertain significance. Objective.— To determine the best testing algorithm for patients with lung cancer in our clinical practice. Design.— Two testing approaches for metastatic lung adenocarcinoma were offered between 2012–2015. One approach was reflex testing for an 8-gene panel composed of DNA Sanger sequencing for EGFR, KRAS, PIK3CA, and BRAF and fluorescence in situ hybridization for ALK, ROS1, MET, and RET. At the oncologist's request, a subset of tumors tested by the 8-gene panel was subjected to a 50-gene Ion AmpliSeq Cancer Panel. Results.— Of 1200 non–small cell lung carcinomas (NSCLCs), 57 including 46 adenocarcinomas and NSCLCs, not otherwise specified; 7 squamous cell carcinomas (SCCs); and 4 large cell neuroendocrine carcinomas (LCNECs) were subjected to Ion AmpliSeq Cancer Panel. Ion AmpliSeq Cancer Panel detected 9 potentially actionable variants in 29 adenocarcinomas that were wild type by the 8-gene panel testing (9 of 29, 31.0%) in the following genes: ERBB2 (3 of 29, 10.3%), STK11 (2 of 29, 6.8%), PTEN (2 of 29, 6.8%), FBXW7 (1 of 29, 3.4%), and BRAF G469A (1 of 29, 3.4%). Four SCCs and 2 LCNECs showed investigational genomic alterations. Conclusions.— The NGS approach would result in the identification of a significant number of actionable gene alterations, increasing the therapeutic options for patients with advanced NSCLCs.

scholarly journals Investigation of neglected protists Blastocystis sp. and Dientamoeba fragilis in immunocompetent and immunodeficient diarrheal patients using both conventional and molecular methods

2021 ◽  
Vol 15 (10) ◽  
pp. e0009779
Author(s):  
Fakhriddin Sarzhanov ◽  
Funda Dogruman-Al ◽  
Monica Santin ◽  
Jenny G. Maloney ◽  
Ayse Semra Gureser ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Gastrointestinal Symptoms ◽  
Molecular Methods ◽  
Clinical Samples ◽  
Rrna Gene ◽  
Next Generation ◽  
Dientamoeba Fragilis ◽  
Significant Difference ◽  
Generation Sequencing ◽  
Immunocompetent Patients

Introduction The clinical significance of Blastocystis sp. and Dientamoeba fragilis in patients with gastrointestinal symptoms is a controversial issue. Since the pathogenicity of these protists has not been fully elucidated, testing for these organisms is not routinely pursued by most laboratories and clinicians. Thus, the prevalence of these organisms and the subtypes of Blastocystis sp. in human patients in Turkey are not well characterized. This study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in the diarrheic stool samples of immunodeficient and immunocompetent patients using conventional and molecular methods and to identify Blastocystis sp. subtypes using next generation sequencing. Material and methods Individual stool specimens were collected from 245 immunodeficient and 193 immunocompetent diarrheic patients between March 2017 and December 2019 at the Gazi University Training and Research Hospital in Ankara, Turkey. Samples were screened for Blastocystis sp. and D. fragilis by conventional and molecular methods. Molecular detection of both protists was achieved by separate qPCRs targeting a partial fragment of the SSU rRNA gene. Next generation sequencing was used to identify Blastocystis sp. subtypes. Results The prevalence of Blastocystis sp. and D. fragilis was 16.7% and 11.9%, respectively as measured by qPCR. The prevalence of Blastocystis sp. and D. fragilis was lower in immunodeficient patients (12.7% and 10.6%, respectively) compared to immunocompetent patients (21.8% and 13.5%, respectively). Five Blastocystis sp. subtypes were identified and the following subtype distribution was observed: ST3 54.4% (n = 37), ST2 16.2% (n = 11), ST1 4.4% (n = 3), ST6 2.9% (n = 2), ST4 1.5% (n = 1), ST2/ST3 11.8% (n = 8) and ST1/ST3 8.8% (n = 6). There was no statistically significant difference in the distribution of Blastocystis sp. subtypes between immunocompetent and immunodeficient patients. Conclusion and recommendation Our findings demonstrated that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea. This study is the first to use next generation sequencing to address the presence of Blastocystis sp. mixed subtypes and intra-subtype variability in clinical samples in Turkey.

scholarly journals Understanding Inherited Risk in Unselected Newly Diagnosed Patients With Endometrial Cancer

2019 ◽  
pp. 1-15
Author(s):  
Karen A. Cadoo ◽  
Diana L. Mandelker ◽  
Semanti Mukherjee ◽  
Carolyn Stewart ◽  
Deborah DeLair ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Next Generation Sequencing ◽  
Lynch Syndrome ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Cancer Predisposition ◽  
Next Generation ◽  
Germline Variants ◽  
Predisposition Genes ◽  
Generation Sequencing

PURPOSE Mutations in DNA mismatch repair genes and PTEN, diagnostic of Lynch and Cowden syndromes, respectively, represent the only established inherited predisposition genes in endometrial cancer to date. The prevalence of other cancer predisposition genes remains unclear. We determined the prevalence of pathogenic germline variants in unselected patients with endometrial cancer scheduled for surgical consultation. PATIENTS AND METHODS Patients prospectively consented (April 2016 to May 2017) to an institutional review board–approved protocol of tumor-normal sequencing via a custom next-generation sequencing panel—the Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets—that yielded germline results for more than 75 cancer predisposition genes. Tumors were assessed for microsatellite instability. Per institutional standards, all tumors underwent Lynch syndrome screening via immunohistochemistry (IHC) for mismatch repair proteins. RESULTS Of 156 patients who consented to germline genetic testing, 118 (76%) had stage I disease. In 104 patients (67%), tumors were endometrioid, and 60 (58%) of those tumors were grade 1. Twenty-four pathogenic germline variants were identified in 22 patients (14%): seven (4.5%) had highly penetrant cancer syndromes and 15 (9.6%) had variants in low-penetrance, moderate-penetrance, or recessive genes. Of these, five (21%) were in Lynch syndrome genes (two MSH6, two PMS2, and one MLH1). All five tumors had concordant IHC staining; two (40%) were definitively microsatellite instability–high by next-generation sequencing. One patient had a known BRCA1 mutation, and one had an SMARCA4 deletion. The remaining 17 variants (71%) were incremental findings in low- and moderate-penetrance variants or genes associated with recessive disease. CONCLUSION In unselected patients with predominantly low-risk, early-stage endometrial cancer, germline multigene panel testing identified cancer predisposition gene variants in 14%. This finding may have implications for future cancer screening and risk-reduction recommendations. Universal IHC screening for Lynch syndrome successfully identifies the majority (71%) of high-penetrance germline mutations.

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