scholarly journals The Mutational Concordance of Fixed Formalin Paraffin Embedded and Fresh Frozen Gastro-Oesophageal Tumours Using Whole Exome Sequencing

2021 ◽  
Vol 10 (2) ◽  
pp. 215
Author(s):  
Irene Y. Chong ◽  
Naureen Starling ◽  
Alistair Rust ◽  
John Alexander ◽  
Lauren Aronson ◽  
...  
Keyword(s):  
Clinical Study ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Mutant Allele ◽  
Prospective Clinical Study ◽  
Sequencing Data ◽  
Whole Exome ◽  
Ffpe Samples ◽  
Fresh Frozen ◽  
Oesophageal Tumour

1. Background: The application of massively parallel sequencing has led to the identification of aberrant druggable pathways and somatic mutations within therapeutically relevant genes in gastro-oesophageal cancer. Given the widespread use of formalin-fixed paraffin-embedded (FFPE) samples in the study of this disease, it would be beneficial, especially for the purposes of biomarker evaluation, to assess the concordance between comprehensive exome-wide sequencing data from archival FFPE samples originating from a prospective clinical study and those derived from fresh-frozen material. 2. Methods: We analysed whole-exome sequencing data to define the mutational concordance of 16 matched fresh-frozen and FFPE gastro-oesophageal tumours (N = 32) from a prospective clinical study. We assessed DNA integrity prior to sequencing and then identified coding mutations in genes that have previously been implicated in other cancers. In addition, we calculated the mutant-allele heterogeneity (MATH) for these samples. 3. Results: Although there was increased degradation of DNA in FFPE samples compared with frozen samples, sequencing data from only two FFPE samples failed to reach an adequate mapping quality threshold. Using a filtering threshold of mutant read counts of at least ten and a minimum of 5% variant allele frequency (VAF) we found that there was a high median mutational concordance of 97% (range 80.1–98.68%) between fresh-frozen and FFPE gastro-oesophageal tumour-derived exomes. However, the majority of FFPE tumours had higher mutant-allele heterogeneity (MATH) scores when compared with corresponding frozen tumours (p < 0.001), suggesting that FFPE-based exome sequencing is likely to over-represent tumour heterogeneity in FFPE samples compared to fresh-frozen samples. Furthermore, we identified coding mutations in 120 cancer-related genes, including those associated with chromatin remodelling and Wnt/β-catenin and Receptor Tyrosine Kinase signalling. 4. Conclusions: These data suggest that comprehensive genomic data can be generated from exome sequencing of selected DNA samples extracted from archival FFPE gastro-oesophageal tumour tissues within the context of prospective clinical trials.

scholarly journals A Survey of Computational Tools to Analyze and Interpret Whole Exome Sequencing Data

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jennifer D. Hintzsche ◽  
William A. Robinson ◽  
Aik Choon Tan
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Sequencing Data ◽  
Disease Treatment ◽  
Computational Tools ◽  
Whole Exome ◽  
Data Production ◽  
Whole Exome Sequencing Data ◽  
Computationally Intensive ◽  
Generation Technology

Whole Exome Sequencing (WES) is the application of the next-generation technology to determine the variations in the exome and is becoming a standard approach in studying genetic variants in diseases. Understanding the exomes of individuals at single base resolution allows the identification of actionable mutations for disease treatment and management. WES technologies have shifted the bottleneck in experimental data production to computationally intensive informatics-based data analysis. Novel computational tools and methods have been developed to analyze and interpret WES data. Here, we review some of the current tools that are being used to analyze WES data. These tools range from the alignment of raw sequencing reads all the way to linking variants to actionable therapeutics. Strengths and weaknesses of each tool are discussed for the purpose of helping researchers make more informative decisions on selecting the best tools to analyze their WES data.

scholarly journals EthSEQ: ethnicity annotation from whole exome sequencing data

2017 ◽  
Vol 33 (15) ◽  
pp. 2402-2404 ◽  
Author(s):  
Alessandro Romanel ◽  
Tuo Zhang ◽  
Olivier Elemento ◽  
Francesca Demichelis
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Sequencing Data ◽  
Exome Sequencing Data ◽  
Whole Exome ◽  
Whole Exome Sequencing Data

scholarly journals HPexome: An automated tool for processing whole-exome sequencing data

SoftwareX ◽  
2020 ◽  
Vol 11 ◽  
pp. 100478
Author(s):  
Lucas L. Cendes ◽  
Welliton de Souza ◽  
Iscia Lopes-Cendes ◽  
Benilton S. Carvalho
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Sequencing Data ◽  
Exome Sequencing Data ◽  
Whole Exome ◽  
Whole Exome Sequencing Data ◽  
Automated Tool

scholarly journals Assessing reliability of intra-tumor heterogeneity estimates from single sample whole exome sequencing data

PLoS ONE ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. e0224143 ◽  
Author(s):  
Judith Abécassis ◽  
Anne-Sophie Hamy ◽  
Cécile Laurent ◽  
Benjamin Sadacca ◽  
Hélène Bonsang-Kitzis ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Tumor Heterogeneity ◽  
Single Sample ◽  
Sequencing Data ◽  
Exome Sequencing Data ◽  
Whole Exome ◽  
Whole Exome Sequencing Data

scholarly journals Comparison of Accuracy of Whole-Exome Sequencing with Formalin-Fixed Paraffin-Embedded and Fresh Frozen Tissue Samples

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0144162 ◽  
Author(s):  
Ensel Oh ◽  
Yoon-La Choi ◽  
Mi Jeong Kwon ◽  
Ryong Nam Kim ◽  
Yu Jin Kim ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Tissue Samples ◽  
Whole Exome ◽  
Formalin Fixed Paraffin ◽  
Frozen Tissue ◽  
Formalin Fixed Paraffin Embedded ◽  
Fresh Frozen ◽  
Formalin Fixed

Discovery of the First Pathogenic Human EPO Mutation Provides Mechanistic Insight into Cytokine Signaling

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 331-331
Author(s):  
Ah Ram Kim ◽  
Jacob C Ulirsch ◽  
Stephan Wilmes ◽  
Ekrem Unal ◽  
Ignacio Moraga ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Fluorescent Imaging ◽  
Binding Kinetics ◽  
Wild Type ◽  
Sequencing Data ◽  
Exome Sequencing Data ◽  
Whole Exome ◽  
Whole Exome Sequencing Data

Abstract Congenital hypoplastic or Diamond-Blackfan anemia (DBA) is a rare bone marrow failure disorder characterized by a paucity of red blood cells and their precursors in the bone marrow. The majority of cases of DBA are due to haploinsufficient mutations in ribosomal protein genes and in rare cases result from GATA1 mutations. However, nearly half of the DBA cases do not have an identified genetic etiology. While analyzing whole exome sequencing data from a cohort of over 450 patients with a clinical diagnosis of DBA, we encountered the case of a male child of a first cousin consanguineous union who was diagnosed with DBA as an infant and remained transfusion dependent. The patient responded to corticosteroid therapy for a year as a toddler, but this treatment was discontinued due to side effects. The patient subsequently remained transfusion dependent and at 6 years of age an allogeneic bone marrow transplant from a matched maternal aunt was performed. Surprisingly, despite achievement of robust donor chimerism, the patient remained transfusion dependent. Unfortunately the patient developed severe graft-versus-host disease and died of resultant complications. Both the potential recessive nature of the mutation, given parental consanguinity, and the lack of anemia correction following transplant made this case extremely unusual. Thus we evaluated this patient's whole exome sequencing data. We identified a homozygous recessive mutation in the erythropoietin gene (EPO), which resulted in an R150Q substitution in the mature EPO protein. This mutation was absent from a cohort of 60,706 individuals depleted for Mendelian disease and fit the model of complete penetrance in the family. The R150Q mutation was expected to disrupt the high-affinity binding site to the EPO receptor (EPOR). However, we found by producing recombinant proteins that the EPO R150Q mutation only reduced the EPOR binding affinity by 3-fold. Surprisingly, the patient had an over 100-fold elevation in their serum EPO levels, suggesting that this mutation did not cause disease through altered affinity. Rather we observed altered EPOR binding kinetics by this mutant ligand. There was a slightly increased on-rate with a much faster dissociation rate (t1/2 of 10 seconds for the mutant vs. 6 minutes for the wild type). Using human erythroid cells and primary hematopoietic stem and progenitor cells, we could show that this mutant ligand never reached the same efficacy as the wild type (WT) EPO in promoting erythroid differentiation and proliferation. To better characterize this abnormal activity, we examined downstream signaling responses. We found identical phosphorylation of STAT5 at maximally potent concentrations of the WT (1 nM) and R150Q mutant (100 nM) EPO. By surveying a broad array of >120 phosphorylation events using intracellular flow cytometry, we demonstrated that maximal levels of STAT3 and STAT1 phosphorylation were reduced by 30% and 25%, respectively, with the R150Q (100 nM) compared to WT (1 nM) EPO. To determine the mechanistic basis for variation in downstream effector activation by the R150Q mutant ligand, we used inhibitors of both the JAK2 kinase and the SHP1/2 phosphatases that are respectively up- and downstream of STAT phosphorylation. While SHP1/2 inhibition did not alter STAT phosphorylation, JAK2 inhibition by ruxolitinib more potently inhibited STAT1/3 phosphorylation compared to STAT5. Interestingly, treatment with a low dose of ruxolitinib (40 nM) reduced erythroid proliferation to the same extent at maximally potent concentrations of the WT or R150Q EPO, demonstrating that the impairment in signaling by the R150Q EPO was primarily due to reduced JAK2 activity. Finally, we utilized single molecule fluorescent imaging of EPOR dimerization at the intact cell surface to directly show that the kinetically-biased R150Q EPO has a reduced ability to promote productive dimerization as compared to the WT EPO, even at maximally potent concentrations. Collectively, our results demonstrate how the R150Q mutant EPO - the first pathogenic mutation in EPO identified in humans - results in biased agonism of EPOR signaling through reduced receptor dimerization and consequently impaired JAK2 activation. More broadly our findings reveal how variation of cytokine-receptor binding kinetics can be used to tune downstream responses, which has broad implications for modulating the activity of numerous hematopoietic cytokines. Disclosures No relevant conflicts of interest to declare.

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