1
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Shin JC, Jeong JY, Son SG, Choi SH, Nam HC, Yoon TH, Kim HJ, Choi DG, Lee H, Lee U, Yang SM, Kang I, Jung DY, Lee HW, Lee MK, Lee TJ, Kim G, Park HO, Lee SW. Developing centrifugal force real-time digital PCR for detecting extremely low DNA concentration. Sci Rep 2024; 14:11522. [PMID: 38769102 DOI: 10.1038/s41598-024-62199-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024] Open
Abstract
Digital PCR (dPCR) is a technique for absolute quantification of nucleic acid molecules. To develop a dPCR technique that enables more accurate nucleic acid detection and quantification, we established a novel dPCR apparatus known as centrifugal force real-time dPCR (crdPCR). This system is efficient than other systems with only 2.14% liquid loss by dispensing samples using centrifugal force. Moreover, we applied a technique for analyzing the real-time graph of the each micro-wells and distinguishing true/false positives using artificial intelligence to mitigate the rain, a persistent issue with dPCR. The limits of detection and quantification were 1.38 and 4.19 copies/μL, respectively, showing a two-fold higher sensitivity than that of other comparable devices. With the integration of this new technology, crdPCR will significantly contribute to research on next-generation PCR targeting absolute micro-analysis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ukyeol Lee
- RevoSketch Inc., Daejeon, Republic of Korea
| | | | - Il Kang
- RevoSketch Inc., Daejeon, Republic of Korea
| | | | | | - Moon-Keun Lee
- Center for Nano Bio Development, National NanoFab Center (NNFC), Daejeon, Republic of Korea
| | - Tae Jae Lee
- Center for Nano Bio Development, National NanoFab Center (NNFC), Daejeon, Republic of Korea
| | - Geehong Kim
- Nano-Convergence Systems Research Division, Korea Institute of Machinery & Materials, Daejeon, Republic of Korea
| | - Han-Oh Park
- Bioneer Corporation, Daejeon, Republic of Korea
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2
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Casmil IC, Huang C, Blakney AK. A duplex droplet digital PCR assay for absolute quantification and characterization of long self-amplifying RNA. Sci Rep 2023; 13:19050. [PMID: 37923834 PMCID: PMC10624827 DOI: 10.1038/s41598-023-46314-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023] Open
Abstract
Self-amplifying messenger ribonucleic acid (saRNA) provides extended expression of genes of interest by encoding an alphavirus-derived RNA replicase and thus is 2-3 times larger than conventional messenger RNA. However, quality assessment of long RNA transcripts is challenging using standard techniques. Here, we utilized a multiplex droplet digital polymerase chain reaction (ddPCR) assay to assess the quality of saRNA produced from an in vitro transcription reaction and the replication kinetics in human cell lines. Using the one-step reverse transcription ddPCR, we show that an in vitro transcription generates 50-60% full-length saRNA transcripts. However, we note that the two-step reverse transcription ddPCR assay results in a 20% decrease from results obtained using the one-step and confirmed using capillary gel electrophoresis. Additionally, we provided three formulas that differ in the level of stringency and assumptions made to calculate the fraction of intact saRNA. Using ddPCR, we also showed that subgenomic transcripts of saRNA were 19-to-108-fold higher than genomic transcripts at different hours post-transfection of mammalian cells in copies. Therefore, we demonstrate that multiplex ddPCR is well suited for quality assessment of long RNA and replication kinetics of saRNA based on absolute quantification.
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Affiliation(s)
- Irafasha C Casmil
- Michael Smith Laboratories, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Cynthia Huang
- Michael Smith Laboratories, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Anna K Blakney
- Michael Smith Laboratories, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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3
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Sahm F, Brandner S, Bertero L, Capper D, French PJ, Figarella-Branger D, Giangaspero F, Haberler C, Hegi ME, Kristensen BW, Kurian KM, Preusser M, Tops BBJ, van den Bent M, Wick W, Reifenberger G, Wesseling P. Molecular diagnostic tools for the World Health Organization (WHO) 2021 classification of gliomas, glioneuronal and neuronal tumors; an EANO guideline. Neuro Oncol 2023; 25:1731-1749. [PMID: 37279174 PMCID: PMC10547522 DOI: 10.1093/neuonc/noad100] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Indexed: 06/08/2023] Open
Abstract
In the 5th edition of the WHO CNS tumor classification (CNS5, 2021), multiple molecular characteristics became essential diagnostic criteria for many additional CNS tumor types. For those tumors, an integrated, "histomolecular" diagnosis is required. A variety of approaches exists for determining the status of the underlying molecular markers. The present guideline focuses on the methods that can be used for assessment of the currently most informative diagnostic and prognostic molecular markers for the diagnosis of gliomas, glioneuronal and neuronal tumors. The main characteristics of the molecular methods are systematically discussed, followed by recommendations and information on available evidence levels for diagnostic measures. The recommendations cover DNA and RNA next-generation-sequencing, methylome profiling, and select assays for single/limited target analyses, including immunohistochemistry. Additionally, because of its importance as a predictive marker in IDH-wildtype glioblastomas, tools for the analysis of MGMT promoter methylation status are covered. A structured overview of the different assays with their characteristics, especially their advantages and limitations, is provided, and requirements for input material and reporting of results are clarified. General aspects of molecular diagnostic testing regarding clinical relevance, accessibility, cost, implementation, regulatory, and ethical aspects are discussed as well. Finally, we provide an outlook on new developments in the landscape of molecular testing technologies in neuro-oncology.
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Affiliation(s)
- Felix Sahm
- Department of Neuropathology, University Hospital Heidelberg, Heidelberg, Germany
- CCU Neuropathology, German Concortium for Translational Cancer Research (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Brandner
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology and Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, UK
| | - Luca Bertero
- Pathology Unit, Department of Medical Sciences, University of Turin, Turin, Italy
| | - David Capper
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Pim J French
- Department of Neurology, Brain Tumor Center at Erasmus MC Cancer Center, 3015 GD Rotterdam, The Netherlands
| | - Dominique Figarella-Branger
- Aix-Marseille University, APHM, CNRS, INP, Institute Neurophysiopathol, CHU Timone, Service d’Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Felice Giangaspero
- Department of Radiological, Oncological and Anatomo-Pathological Sciences, University Sapienza of Rome, Rome, Italy
| | - Christine Haberler
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Austria
| | - Monika E Hegi
- Neuroscience Research Center and Neurosurgery, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Bjarne W Kristensen
- Department of Clinical Medicine and Biotech Research and Innovation Center (BRIC), University of Copenhagen, Denmark
- Department of Pathology, The Bartholin Institute, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Matthias Preusser
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Austria
| | - Bastiaan B J Tops
- Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Martin van den Bent
- The Brain Tumor Center at Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - Wolfgang Wick
- Department of Neurology and Neurooncology Program, National Center for Tumor Diseases, Heidelberg University Hospital
- Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Guido Reifenberger
- Institute of Neuropathology, Heinrich Heine University, Medical Faculty, and University Hospital Düsseldorf, and German Cancer Consortium (DKTK), Partner Site Essen/Düsseldorf, Düsseldorf, Germany
| | - Pieter Wesseling
- Department of Pathology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands (P.W.)
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4
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Droplet Digital PCR (ddPCR) as a Novel Technology in Detecting CTNNB1 Mutations in Desmoid Fibromatosis. Appl Immunohistochem Mol Morphol 2022; 30:662-667. [PMID: 36227098 DOI: 10.1097/pai.0000000000001076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/18/2022] [Indexed: 11/25/2022]
Abstract
Desmoid fibromatosis (DF) is a locally aggressive soft tissue neoplasm with frequent recurrences. DF is characterized by alterations in the Wnt/β-catenin pathway, with the majority showing sporadic mutations in CTNNB1, whereas others have germline mutations in APC. Immunohistochemical staining for β-catenin is often difficult to interpret and can be negative in up to 30% of cases. Prior studies have shown that some DFs lacking nuclear expression of β-catenin may carry activating CTNNB1 mutations. Droplet digital polymerase chain reaction (ddPCR) has been used effectively in detecting mutations in formalin-fixed, paraffin-embedded (FFPE) samples of various cancer types. In this study, we assess the diagnostic utility of ddPCR to detect CTNNB1 mutations in DF with β-catenin expression on immunohistochemistry (IHC), as well as in diagnostically challenging cases. Of the 28 DFs with nuclear β-catenin expression by IHC, 24 cases showed a CTNNB1 mutation by ddPCR using primers against the most common point mutations in CTNNB1. The most frequent mutation was T41A (n=14; 50%), followed by S45F (n=8; 33%) and S45P (n=3;12%). We identified 8 additional (myo)fibroblastic lesions of uncertain classification, which were negative for nuclear β-catenin expression by IHC. We detected CTNNB1 mutations in 3 unknown lesions, including S45F (n=2) and S45P (n=1). ddPCR is a sensitive, rapid and cost-efficient methodology to detect common CTNNB1 mutations in DF, especially in diagnostically challenging cases.
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5
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Rosvall BR, Kostiuk M, Williams J, Matkin A, Harris J, Seikaly H, O'Connell DA, Biron VL. Utility of droplet digital polymerase chain reaction for TERT and BRAF mutational profiling of thyroid nodules. BMC Cancer 2021; 21:1142. [PMID: 34702207 PMCID: PMC8547072 DOI: 10.1186/s12885-021-08810-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/22/2021] [Indexed: 12/07/2022] Open
Abstract
Background Mutations involving BRAF and TERT are important predictors of disease severity in thyroid cancer, but molecular testing is limited by cost and lack of adequate tissue sample. This study aimed to assess the utility of BRAFV600E and TERT testing using droplet digital PCR (ddPCR) as a diagnostic and prognostic tool for thyroid fine needle aspirate biopsy (FNAB). Methods Patients with thyroid nodules were prospectively enrolled from March 2015 to September 2018. Pre-operative FNAB was collected for standard cytology and molecular testing. BRAFV600E and TERT levels were analyzed by ddPCR. Cytology (Bethesda system) and ddPCR results were correlated to surgical pathology. Results A total of 222 patients were enrolled, of which 124 received thyroid surgery. Pre-operative cytology alone with Bethesda ≥5 was 100% specific and 70% sensitive for malignancy on final surgical pathology. BRAFV600E positivity or TERT overexpression was 100% specific and 60.0% sensitive. Combining cytology (Bethesda ≥5) with BRAFV600E and TERT testing increased the sensitivity of a malignant diagnosis to 80.0%. High TERT levels and/or BRAFV600E was associated with aggressive or advanced stage pathology. Conclusions Combining cytology with ddPCR analysis of BRAFV600E and TERT can improve the diagnostic accuracy of thyroid FNAB, and help predict aggressive pathology. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-021-08810-8.
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Affiliation(s)
- Brandon R Rosvall
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Morris Kostiuk
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Jordana Williams
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Ashlee Matkin
- Division of Plastic and Reconstructive Surgery, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
| | - Jeffrey Harris
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Hadi Seikaly
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Daniel A O'Connell
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada
| | - Vincent L Biron
- Division of Otolaryngology - Head and Neck Surgery, Department of Surgery, University of Alberta, 1E4 Walter Mackenzie Center, 8440 112 St, Edmonton, Alberta, T6G 2B7, Canada.
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6
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Barets D, Appay R, Heinisch M, Battistella M, Bouvier C, Chotard G, Le Loarer F, Macagno N, Perbet R, Pissaloux D, Rousseau A, Tauziède-Espariat A, Varlet P, Vasiljevic A, Colin C, Fina F, Figarella-Branger D. Specific and Sensitive Diagnosis of BCOR-ITD in Various Cancers by Digital PCR. Front Oncol 2021; 11:645512. [PMID: 33718245 PMCID: PMC7948083 DOI: 10.3389/fonc.2021.645512] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 01/27/2021] [Indexed: 11/25/2022] Open
Abstract
BCOR is an epigenetic regulator altered by various mechanisms including BCOR-internal tandem duplication (BCOR-ITD) in a wide range of cancers. Six different BCOR-ITD in the 3’-part of the coding sequence of exon 15 have been reported ranging from 89 to 114 bp in length. BCOR-ITD is a common genetic alteration found in clear cell sarcoma of the kidney and primitive myxoid mesenchymal tumor of infancy (PMMTI) and it characterizes a new type of central nervous system tumor: “CNS tumor with BCOR-ITD”. It can also be detected in undifferentiated round cell sarcoma (URCS) and in high-grade endometrial stromal sarcoma (HGESS). Therefore, it is of utmost importance to search for this genetic alteration in these cancers with the most frequent technique being RNA-sequencing. Here, we developed a new droplet PCR assay (dPCR) to detect the six sequences characterizing BCOR-ITD. To achieve this goal, we used a single colored probe to detect both the duplicated region and the normal sequence that acts as a reference. We first generated seven synthetic DNA sequences: ITD0 (the normal sequence) and ITD1 to ITD6 (the duplicated sequences described in the literature) and then we set up the optima dPCR conditions. We validated our assay on 19 samples from a representative panel of human tumors (9 HGNET-BCOR, 5 URCS, 3 HGESS, and 2 PMMTI) in which BCOR-ITD status was known using at least one other method including RNA sequencing, RT-PCR or DNA-methylation profiling for CNS tumors. Our results showed that our technique was 100% sensitive and specific. DPCR detected BCOR-ITD in 13/19 of the cases; in the remaining 6 cases additional RNA-sequencing revealed BCOR gene fusions. To conclude, in the era of histomolecular classification of human tumors, our modified dPCR assay is of particular interest to detect BCOR-ITD since it is a robust and less expensive test that can be applied to a broad spectrum of cancers that share this alteration.
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Affiliation(s)
- Doriane Barets
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Romain Appay
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Marie Heinisch
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Maxime Battistella
- Department of Pathology, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Université de Paris, Inserm U976, Paris, France
| | - Corinne Bouvier
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Guillaume Chotard
- Service de Pathologie, Groupe Hospitalier Pellegrin, CHU de Bordeaux, Bordeaux, France
| | | | - Nicolas Macagno
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Romain Perbet
- Institute of Pathology, CHU Lille, Lille, France.,LilNCog, Lille Neuroscience and Cognition, Univ. Lille, Inserm, CHU Lille, U1172, Lille, France
| | - Daniel Pissaloux
- Department of Translational Research and Innovation, Léon Bérard Cancer Center, Lyon, France.,Claude Bernard University Lyon 1, INSERM 1052, CNRS 5286, Cancer Research Center of Lyon, Centre Léon Bérard, Lyon, France
| | - Audrey Rousseau
- Département de Pathologie Cellulaire et Tissulaire, CHU Angers, Angers, France
| | - Arnaud Tauziède-Espariat
- Department of Neuropathology, GHU Paris-Psychiatrie Et Neurosciences, Sainte-Anne Hospital, Paris, France
| | - Pascale Varlet
- Department of Neuropathology, GHU Paris-Psychiatrie Et Neurosciences, Sainte-Anne Hospital, Paris, France
| | - Alexandre Vasiljevic
- Centre de Pathologie Est, Groupement Hospitalier Est, Hospices Civils de Lyon, Bron, France
| | - Carole Colin
- Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Frédéric Fina
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,ID Solutions, Research and Development, Grabels, France
| | - Dominique Figarella-Branger
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
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7
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Appay R, Fina F, Barets D, Gallardo C, Nanni-Metellus I, Scavarda D, Henaff D, Vincent J, Grewis L, Pourquier P, Colin C, Figarella-Branger D. Multiplexed Droplet Digital PCR Assays for the Simultaneous Screening of Major Genetic Alterations in Tumors of the Central Nervous System. Front Oncol 2020; 10:579762. [PMID: 33282733 PMCID: PMC7689380 DOI: 10.3389/fonc.2020.579762] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/15/2020] [Indexed: 01/18/2023] Open
Abstract
The increased integration of molecular alterations to define tumor type or grade in central nervous system (CNS) tumor classification brings new challenges for the pathologist to make the best use of a precious limited tissue specimen for molecular studies. Within the different methods available to identify gene alterations, the droplet digital PCR (dPCR) constitutes a rapid, cost-effective, and very sensitive tool. In this study, we describe the development and validation of five multiplexed dPCR assays to detect major CNS biomarkers by using only small amounts of DNA extracted from formalin-fixed paraffin-embedded specimens. When compared to HRM-sequencing, NGS-sequencing, RNA-sequencing, or simplex digital PCR assays used as “gold standard” methods, these multiplexed dPCR assays displayed 100% specificity and sensitivity for the simultaneous detection of: 1/BRAF V600E mutation and KIAA1549:BRAF fusion; 2/FGFR1 N546K and K656E mutations and FGFR1 duplication; 3/H3F3A K27M and G34R/V mutations; 4/IDH1 R132X and IDH2 R172X mutations; and 5/TERT promoter mutations C228T and C250T. In light of the increased integration of molecular alteration, we believe that such strategies might help laboratories to optimize their screening strategies for routine diagnosis of pediatric and adult CNS tumors.
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Affiliation(s)
- Romain Appay
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Frederic Fina
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,ID Solutions, Research and Development, Grabels, France
| | - Doriane Barets
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Catherine Gallardo
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France
| | - Isabelle Nanni-Metellus
- APHM, CHU Nord, Service de Transfert d'Oncologie Biologique, Laboratoire de Biologie Médicale, Marseille, France
| | - Didier Scavarda
- APHM, CHU Timone, Service de Neurochirurgie pédiatrique, Marseille, France
| | - Daniel Henaff
- ID Solutions, Research and Development, Grabels, France
| | | | - Lise Grewis
- ID Solutions, Research and Development, Grabels, France
| | | | - Carole Colin
- Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Dominique Figarella-Branger
- APHM, CHU Timone, Service d'Anatomie Pathologique et de Neuropathologie, Marseille, France.,Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
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8
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Entering the Pantheon of 21 st Century Molecular Biology Tools: A Perspective on Digital PCR. Methods Mol Biol 2019; 1768:3-10. [PMID: 29717434 DOI: 10.1007/978-1-4939-7778-9_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
After several decades of relatively modest use, in the last several years digital PCR (dPCR) has grown to become the new gold standard for nucleic acid quantification. This coincides with the commercial availability of scalable, affordable, and reproducible droplet-based dPCR platforms in the past five years and has led to its rapid dissemination into diverse research fields and testing applications. Among these, it has been adopted most vigorously into clinical oncology where it is beginning to be used for plasma genotyping in cancer patients undergoing treatment. Additionally, innovation across the scientific community has extended the benefits of reaction partitioning beyond DNA and RNA quantification alone, and demonstrated its usefulness in evaluating DNA size and integrity, the physical linkage of colocalized markers, levels of enzyme activity and specific cation concentrations in a sample, and more. As dPCR technology gains in popularity and breadth, its power and simplicity can often be taken for granted; thus, the reader is reminded that due diligence must be exercised in order to make claims not only of precision but also of accuracy in their measurements.
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9
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Somasundaram DB, Aravindan S, Yu Z, Jayaraman M, Tran NTB, Li S, Herman TS, Aravindan N. Droplet digital PCR as an alternative to FISH for MYCN amplification detection in human neuroblastoma FFPE samples. BMC Cancer 2019; 19:106. [PMID: 30691436 PMCID: PMC6348625 DOI: 10.1186/s12885-019-5306-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 01/16/2019] [Indexed: 11/17/2022] Open
Abstract
Background MYCN amplification directly correlates with the clinical course of neuroblastoma and poor patient survival, and serves as the most critical negative prognostic marker. Although fluorescence in situ hybridization (FISH) remains the gold standard for clinical diagnosis of MYCN status in neuroblastoma, its limitations warrant the identification of rapid, reliable, less technically challenging, and inexpensive alternate approaches. Methods In the present study, we examined the concordance of droplet digital PCR (ddPCR, in combination with immunohistochemistry, IHC) with FISH for MYCN detection in a panel of formalin-fixed paraffin-embedded (FFPE) human neuroblastoma samples. Results In 112 neuroblastoma cases, ddPCR analysis demonstrated a 96–100% concordance with FISH. Consistently, IHC grading revealed 92–100% concordance with FISH. Comparing ddPCR with IHC, we observed a concordance of 95–98%. Conclusions The results demonstrate that MYCN amplification status in NB cases can be assessed with ddPCR, and suggest that ddPCR could be a technically less challenging method of detecting MYCN status in FFPE specimens. More importantly, these findings illustrate the concordance between FISH and ddPCR in the detection of MYCN status. Together, the results suggest that rapid, less technically demanding, and inexpensive ddPCR in conjunction with IHC could serve as an alternate approach to detect MYCN status in NB cases, with near-identical sensitivity to that of FISH.
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Affiliation(s)
- Dinesh Babu Somasundaram
- Departments of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA
| | | | - Zhongxin Yu
- Department of Pathology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 451, Oklahoma City, OK, 73104, USA
| | - Muralidharan Jayaraman
- Stephenson Cancer Center, Oklahoma City, OK, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 553, Oklahoma City, OK, 73104, USA
| | - Ngoc T B Tran
- Department of Pathology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 451, Oklahoma City, OK, 73104, USA
| | - Shibo Li
- Department of Pediatrics, University of Oklahoma Health Sciences Center, 1200 Children's Ave. Ste 14000, Oklahoma City, OK, 73104, USA
| | - Terence S Herman
- Departments of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA.,Stephenson Cancer Center, Oklahoma City, OK, USA
| | - Natarajan Aravindan
- Departments of Radiation Oncology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA. .,Department of Pathology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, BMSB 451, Oklahoma City, OK, 73104, USA. .,Department of Anesthesiology, University of Oklahoma Health Sciences Center, 920 SL Young Blvd #1140, Oklahoma City, OK, 73104-5036, USA.
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10
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Monico J, Miller B, Rezeanu L, May W, Sullivan DC. Fibroblast growth factor receptor 1 amplification in laryngeal squamous cell carcinoma. PLoS One 2018; 13:e0186185. [PMID: 29351293 PMCID: PMC5774678 DOI: 10.1371/journal.pone.0186185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/26/2017] [Indexed: 12/17/2022] Open
Abstract
Fibroblast growth factor receptor 1 (FGFR1) has been noted to be amplified in a variety of squamous cell carcinomas (SCCa) of the head, neck, and lung and increased copy number (CN) is a predictor of poor outcomes. FGFR1 is a therapeutic target for lung SCCa and inhibition therapy is currently in clinical trials. Absolute quantification of FGFR1 from formalin fixed paraffin embedded (FFPE) tissue of laryngeal SCCa was examined in this retrospective study. A droplet digital polymerase chain reaction (ddPCR) was used for absolute quantitation of the FGFR1 gene CN. Of the 74 samples analyzed, FGFR1 CN analysis revealed 54% of samples had CN greater than 2 copies/cell (1.8-2.2 copies/cell), and 38% had CN values greater than 3. The mean and standard deviation FGFR1 CN was 4.17 ± 1.46 CN for African American patients (n = 41) and 3.78 ±1.85 CN for Caucasian patients (n = 31). Further, 60.9% of specimens from African Americans demonstrated increased FGFR1 CN compared to 48.4% of Caucasians. Two SCCA samples from Native American demonstrated increased FGFR1 CN (4.19 and 3.01 CN). The level of FGFR1 amplification did not correlate with tumor stage, lymph node staging, or metastasis. In this population, the proportion of patient samples with an FGFR1 amplification was three times higher than in reported for SCCA of the head and neck. Further, increased FGFR1 CN was observed in two racial groups not previously reported: African Americans and Native Americans. However, FGFR1 amplification is not prognostic in laryngeal squamous cell carcinomas.
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Affiliation(s)
- Jesus Monico
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Brandon Miller
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Luminita Rezeanu
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Warren May
- Department of Biostatistics, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Donna C. Sullivan
- Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
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Abstract
Use of digital polymerase chain reaction (dPCR) technology is rapidly growing and diversifying into a range of areas in life science. The release of dPCR commercial systems has facilitated access, leading to recognition of the potential advantages compared to previous quantitative PCR technologies, and the scope for novel applications. The capability of dPCR to deliver unprecedented levels of precision, accuracy, and resolution in quantification of nucleic acids has triggered a strong interest by academia and the life sciences industry in use of this technology as a molecular diagnostic tool. However, the performance of dPCR, as for a "classical" PCR assay, essentially still relies on enzyme-based amplification of nucleic acid using specific reagents and instrumentation. This chapter describes basic concepts, key properties, and important factors to consider for the verification and validation of dPCR measurements.
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Affiliation(s)
| | - Kerry R Emslie
- National Measurement Institute, Lindfield, NSW, Australia
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12
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Shehata HR, Li J, Chen S, Redda H, Cheng S, Tabujara N, Li H, Warriner K, Hanner R. Droplet digital polymerase chain reaction (ddPCR) assays integrated with an internal control for quantification of bovine, porcine, chicken and turkey species in food and feed. PLoS One 2017; 12:e0182872. [PMID: 28796824 PMCID: PMC5552122 DOI: 10.1371/journal.pone.0182872] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 07/26/2017] [Indexed: 11/19/2022] Open
Abstract
Food adulteration and feed contamination are significant issues in the food/feed industry, especially for meat products. Reliable techniques are needed to monitor these issues. Droplet Digital PCR (ddPCR) assays were developed and evaluated for detection and quantification of bovine, porcine, chicken and turkey DNA in food and feed samples. The ddPCR methods were designed based on mitochondrial DNA sequences and integrated with an artificial recombinant plasmid DNA to control variabilities in PCR procedures. The specificity of the ddPCR assays was confirmed by testing both target species and additional 18 non-target species. Linear regression established a detection range between 79 and 33200 copies of the target molecule from 0.26 to 176 pg of fresh animal tissue DNA with a coefficient of determination (R2) of 0.997–0.999. The quantification ranges of the methods for testing fortified heat-processed food and feed samples were 0.05–3.0% (wt/wt) for the bovine and turkey targets, and 0.01–1.0% (wt/wt) for pork and chicken targets. Our methods demonstrated acceptable repeatability and reproducibility for the analytical process for food and feed samples. Internal validation of the PCR process was monitored using a control chart for 74 consecutive ddPCR runs for quantifying bovine DNA. A matrix effect was observed while establishing calibration curves with the matrix type under testing, and the inclusion of an internal control in DNA extraction provides a useful means to overcome this effect. DNA degradation caused by heating, sonication or Taq I restriction enzyme digestion was found to reduce ddPCR readings by as much as 4.5 fold. The results illustrated the applicability of the methods to quantify meat species in food and feed samples without the need for a standard curve, and to potentially support enforcement activities for food authentication and feed control. Standard reference materials matching typical manufacturing processes are needed for future validation of ddPCR assays for absolute quantification of meat species.
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Affiliation(s)
- Hanan R. Shehata
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
- Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
- Microbiology Department, Mansoura University, Mansoura, Egypt
| | - Jiping Li
- Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada
| | - Shu Chen
- Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada
- * E-mail:
| | - Helen Redda
- Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Shumei Cheng
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Nicole Tabujara
- Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada
| | - Honghong Li
- Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada
| | - Keith Warriner
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Robert Hanner
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
- Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada
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14
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Du M, Wang L. 3C-digital PCR for quantification of chromatin interactions. BMC Mol Biol 2016; 17:23. [PMID: 27923366 PMCID: PMC5139078 DOI: 10.1186/s12867-016-0076-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 12/01/2016] [Indexed: 01/16/2023] Open
Abstract
Background Chromosome conformation capture (3C) is a powerful and widely used technique for detecting the physical interactions between chromatin regions in vivo. The principle of 3C is to convert physical chromatin interactions into specific DNA ligation products, which are then detected by quantitative polymerase chain reaction (qPCR). However, 3C-qPCR assays are often complicated by the necessity of normalization controls to correct for amplification biases. In addition, qPCR is often limited to a certain cycle number, making it difficult to detect fragment ligations with low frequency. Recently, digital PCR (dPCR) technology has become available, which allows for highly sensitive nucleic acid quantification. Main advantage of dPCR is its high precision of absolute nucleic acid quantification without requirement of normalization controls. Results To demonstrate the utility of dPCR in quantifying chromatin interactions, we examined two prostate cancer risk loci at 8q24 and 2p11.2 for their interaction target genes MYC and CAPG in LNCaP cell line. We designed anchor and testing primers at known regulatory element fragments and target gene regions, respectively. dPCR results showed that interaction frequency between the regulatory element and MYC gene promoter was 0.7 (95% CI 0.40–1.10) copies per 1000 genome copies while other regions showed relatively low ligation frequencies. The dPCR results also showed that the ligation frequencies between the regulatory element and two EcoRI fragments containing CAPG gene promoter were 1.9 copies (95% CI 1.41–2.47) and 1.3 copies per 1000 genome copies (95% CI 0.76–1.92), respectively, while the interaction signals were reduced on either side of the promoter region of CAPG gene. Additionally, we observed comparable results from 3C-dPCR and 3C-qPCR at 2p11.2 in another cell line (DU145). Conclusions Compared to traditional 3C-qPCR, our results show that 3C-dPCR is much simpler and more sensitive to detect weak chromatin interactions. It may eliminate multiple and complex normalization controls and provide accurate calculation of proximity-based fragment ligation frequency. Therefore, we recommend 3C-dPCR as a preferred method for sensitive detection of low frequency chromatin interactions. Electronic supplementary material The online version of this article (doi:10.1186/s12867-016-0076-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Meijun Du
- Department of Pathology and MCW Cancer Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Liang Wang
- Department of Pathology and MCW Cancer Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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Hughesman CB, Lu XJD, Liu KYP, Zhu Y, Poh CF, Haynes C. A Robust Protocol for Using Multiplexed Droplet Digital PCR to Quantify Somatic Copy Number Alterations in Clinical Tissue Specimens. PLoS One 2016; 11:e0161274. [PMID: 27537682 PMCID: PMC4990255 DOI: 10.1371/journal.pone.0161274] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 06/25/2016] [Indexed: 12/24/2022] Open
Abstract
The ability of droplet digital PCR (ddPCR) to accurately determine the concentrations of amplifiable targets makes it a promising platform for measuring copy number alterations (CNAs) in genomic biomarkers. However, its application to clinical samples, particularly formalin-fixed paraffin-embedded specimens, will require strategies to reliably determine CNAs in DNA of limited quantity and quality. When applied to cancerous tissue, those methods must also account for global genetic instability and the associated probability that the abundance(s) of one or more chosen reference loci do not represent the average ploidy of cells comprising the specimen. Here we present an experimental design strategy and associated data analysis tool that enables accurate determination of CNAs in a panel of biomarkers using multiplexed ddPCR. The method includes strategies to optimize primer and probes design to cleanly segregate droplets in the data output from reaction wells amplifying multiple independent templates, and to correct for bias from artifacts such as DNA fragmentation. We demonstrate how a panel of reference loci can be used to determine a stable CNA-neutral benchmark. These innovations, when taken together, provide a comprehensive strategy that can be used to reliably detect biomarker CNAs in DNA extracted from either frozen or FFPE tissue biopsies.
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Affiliation(s)
- Curtis B. Hughesman
- Department of Oral Medical Biological Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - X. J. David Lu
- Department of Oral Medical Biological Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Kelly Y. P. Liu
- Department of Oral Medical Biological Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Yuqi Zhu
- Department of Oral Medical Biological Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Catherine F. Poh
- Department of Oral Medical Biological Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, V6T 2B5, Canada
- Department of Integrative Oncology, British Columbia Cancer Research Centre, Vancouver, British Columbia, V5Z 1L3, Canada
- * E-mail: (CH); (CP)
| | - Charles Haynes
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
- RES’EAU NSERC Research Network, Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- * E-mail: (CH); (CP)
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Larsen AC, Dahl C, Dahmcke CM, Lade-Keller J, Siersma VD, Toft PB, Coupland SE, Prause JU, Guldberg P, Heegaard S. BRAF mutations in conjunctival melanoma: investigation of incidence, clinicopathological features, prognosis and paired premalignant lesions. Acta Ophthalmol 2016; 94:463-70. [PMID: 27009410 DOI: 10.1111/aos.13007] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/09/2016] [Indexed: 12/20/2022]
Abstract
PURPOSE To investigate incidence, clinicopathological features and prognosis of BRAF-mutated conjunctival melanoma in Denmark. Furthermore, to determine BRAF mutations in paired premalignant lesions and evaluate immunohistochemical BRAF V600E oncoprotein detection. METHODS Data from 139 patients with conjunctival melanoma (1960-2012) were collected. Archived conjunctival melanoma samples and premalignant lesions were analysed for BRAF mutations using droplet digital polymerase chain reaction (PCR). Results were associated with clinicopathological features and compared with BRAF V600E oncoprotein stainings. RESULTS The overall incidence of conjunctival melanoma (0.5 cases/1 000 000/year) increased during the study period with 0.13 cases/1 000 000/10 years. The increase comprised a higher proportion of patients aged >65 years, epibulbar tumours and tumours developed from a primary acquired melanosis with atypia. BRAF mutations were identified in 39 of 111 (35%) cases. The rate ratio of BRAF-mutated versus BRAF-wild-type melanoma did not change over time. BRAF mutations were associated with T1 stage (p = 0.007), young age (p = 0.001), male gender (p = 0.02), sun-exposed location (p = 0.01), mixed/non-pigmented tumour colour (p = 0.02) and nevus origin (p = 0.005), but did not associate with prognosis. BRAF status in conjunctival melanoma and paired premalignant lesions corresponded in 19 of 20 cases. Immunohistochemistry detected BRAF V600E mutations with a sensitivity of 0.94 and a specificity of 1.00 in newer conjunctival melanoma samples (2000-2012, n = 47). CONCLUSION The incidence of conjunctival melanoma increased in Denmark over 50 years. The proportion of BRAF-mutated conjunctival melanoma was constant. BRAF mutations were identified as early events in conjunctival melanoma, associated with a distinct clinicopathological profile, similar to BRAF-mutated cutaneous melanoma. Immunohistochemical detection of BRAF can be used to assess BRAF V600E mutations.
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Affiliation(s)
- Ann-Cathrine Larsen
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
- Department of Pathology - Rigshospitalet; Copenhagen Denmark
| | - Christina Dahl
- Danish Cancer Society, Research Center; Copenhagen Denmark
| | | | | | - Volkert D. Siersma
- The Research Unit and Section of General Practice; Institute of Public Health, University of Copenhagen; Copenhagen Denmark
| | - Peter B. Toft
- Department of Ophthalmology; Rigshospitalet - Glostrup Hospital; Copenhagen Denmark
| | - Sarah E. Coupland
- Division of Pathology, Department of Molecular and Clinical Medicine; Royal Liverpool University Hospital; Liverpool UK
| | - Jan U. Prause
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
| | - Per Guldberg
- Danish Cancer Society, Research Center; Copenhagen Denmark
| | - Steffen Heegaard
- Department of Pathology - Rigshospitalet; Copenhagen Denmark
- Department of Ophthalmology; Rigshospitalet - Glostrup Hospital; Copenhagen Denmark
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Larsen AC. Conjunctival malignant melanoma in Denmark: epidemiology, treatment and prognosis with special emphasis on tumorigenesis and genetic profile. Acta Ophthalmol 2016; 94 Thesis 1:1-27. [PMID: 27192168 DOI: 10.1111/aos.13100] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Conjunctival malignant melanoma is a rare disease associated with considerable mortality. Most published data have been based on case reports or series of referred patients. In addition, very little is known about the genetic and epigenetic profile of conjunctival melanoma and the resemblance to uveal, cutaneous and mucosal melanoma. The aim was to determine the incidence rate of conjunctival melanoma, and to relate clinicopathological features and treatment to prognosis. A further aim was to determine the prevalence of BRAF mutations in conjunctival melanoma, to determine whether BRAF mutations are early events in pathogenesis, and relate clinicopathological features and prognosis to BRAF-mutation status. Finally, we wanted to identify tumour-specific and prognostic microRNAs in conjunctival melanoma, and to compare these with the microRNA expression of other melanoma subtypes. In order to investigate these rare tumours, we studied all the conjunctival melanomas that had been surgically removed in Denmark over a period of 52 years (1960-2012). Tissue samples, clinical files, pathology reports and follow-up data were collected and re-evaluated. Using droplet digital polymerase chain reaction and immunohistochemistry, we investigated BRAF mutations; and using microRNA expression profiling, we investigated differentially expressed microRNAs. The overall incidence of conjunctival melanoma was 0.5/1 000 000/year, and it increased in Denmark over 52 years. The increase was mainly caused by an increase in older patients (>65 years) and bulbar lesions. Clinicopathological features significantly associated with a poor prognosis were extrabulbar location, involvement of adjacent tissue structures, tumour thickness exceeding 2 mm and local tumour recurrence. Patients undergoing incisional biopsy and/or treatment involving excision without adjuvant therapy fared worse than patients treated with excision and any type of adjuvant treatment. We found that 35% (39/110) of conjunctival melanomas were BRAF-mutated, and the incidence of BRAF mutations was constant over time. BRAF-mutation status corresponded in conjunctival melanoma and paired premalignant lesions. BRAF mutations were more frequent in males, in young patients, and in tumours with a sun-exposed tumour location (bulbar conjunctiva or caruncle), with a mixed or non-pigmented colour, with absence of primary acquired melanosis, and with origin in a nevus. Immunohistochemistry was able to accurately detect BRAF V600E mutations. In univariate analysis, distant metastatic disease was associated with BRAF mutations. No prognostic associations with BRAF mutations were identified in multivariate analyses. MicroRNA expression analysis revealed 25 tumour-specific microRNAs in conjunctival melanoma. Five possibly oncogenic miRNAs (miR-20b-5p, miR-146b-5p, miR-146a-5p, miR-506-3p and miR-509-3p) were up-regulated. Seven microRNAs (miR-30d-5p, miR-138-5p, miR-146a-5p, miR-500a-5p, miR-501-3p, miR-501-5p and miR-502-3p) were significantly and simultaneously up-regulated in both stage T1 and stage T2 tumours, and were associated with increased tumour thickness. The expression of the 25 tumour-specific microRNAs did not differ significantly between conjunctival melanoma and oral or nasal mucosal melanoma. In conclusion, the incidence of conjunctival melanoma increased in the Danish population from 1960 to 2012. From our findings of a distinct pattern of BRAF mutations and differentially expressed microRNAs, it is evident that conjunctival melanoma is closely related to cutaneous and other mucosal melanomas and bears less resemblance to uveal melanomas. This means that conjunctival melanoma patients may benefit from therapies that are effective for cutaneous and mucosal melanoma. Additionally, the identification of several up-regulated microRNAs may prove to be useful as prognostic or therapeutic targets in conjunctival melanoma.
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Affiliation(s)
- Ann-Cathrine Larsen
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
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18
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Zhu Y, Lu D, Lira ME, Xu Q, Du Y, Xiong J, Mao M, Chung HC, Zheng G. Droplet digital polymerase chain reaction detection of HER2 amplification in formalin fixed paraffin embedded breast and gastric carcinoma samples. Exp Mol Pathol 2015; 100:287-93. [PMID: 26626802 DOI: 10.1016/j.yexmp.2015.11.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/24/2015] [Indexed: 01/29/2023]
Abstract
RATIONALE Human epidermal growth factor receptor 2 (HER2) is a key driver of tumorigenesis, and over-expression as a result of HER2 gene amplification has been observed in a number of solid tumors. Recently HER2 has become an important biomarker for the monoclonal antibody treatment of HER2-positive metastatic breast and advanced gastric cancer. The HER2 targeting antibody trastuzumab treatment requires accurate measurement of HER2 levels for proper diagnosis. Droplet digital PCR (ddPCR) with highly direct, precise and absolute nucleic acid quantification could be used to detect HER2 amplification levels. OBJECTIVES Our objective was to evaluate a robust, accurate and less subjective application of ddPCR for HER2 amplification levels and test the assay performance in clinical formalin-fixed paraffin-embedded (FFPE) breast and gastric carcinoma samples. METHODS Genomic DNA from HER2 amplified cell line SK-BR-3 was used to set up the ddPCR assays. The copy number of HER2 was compared to the chromosome 17 centromere reference gene (CEP17), expressed as HER2:CEP17 ratio. Genomic DNAs of FFPE specimens from 145 Asian patients with breast and gastric carcinomas were assayed using both standard methods, immunohistochemistry (IHC) and/or fluorescence in situ hybridization (FISH), and ddPCR. RESULTS Based on 145 clinical breast and gastric carcinoma cases, our study demonstrated a high concordance of ddPCR results to FISH and IHC. In breast cancer specimens, the ddPCR results had high concordance with FISH and IHC defined HER2 status with a sensitivity of 90.9% (30/33) and a specificity of 100% (77/77). In gastric cancer specimens that were concordant in both FISH and IHC, our assay was 95.5% concordant with FISH and IHC (21/22). CONCLUSIONS ddPCR has the advantage of automation and also allows levels of HER2 amplification to be easily evaluated in large numbers of samples, and presents a potential option to define HER2 status.
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Affiliation(s)
- Yazhen Zhu
- Guangdong Provincial Hospital of Traditional Chinese Medicine (GPHTCM), Guangzhou, China
| | - Dan Lu
- Translational Bioscience and Diagnostics, WuXi AppTec Co., Ltd., Waigaoqiao Free Trade Zone, Shanghai, China
| | - Maruja E Lira
- Pfizer Oncology, San Diego, California, United States
| | - Qing Xu
- Translational Bioscience and Diagnostics, WuXi AppTec Co., Ltd., Waigaoqiao Free Trade Zone, Shanghai, China
| | - Yunzhi Du
- Translational Bioscience and Diagnostics, WuXi AppTec Co., Ltd., Waigaoqiao Free Trade Zone, Shanghai, China
| | - Jianghong Xiong
- Translational Bioscience and Diagnostics, WuXi AppTec Co., Ltd., Waigaoqiao Free Trade Zone, Shanghai, China
| | - Mao Mao
- Translational Bioscience and Diagnostics, WuXi AppTec Co., Ltd., Waigaoqiao Free Trade Zone, Shanghai, China.
| | - Hyun Cheol Chung
- Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea.
| | - Guangjuan Zheng
- Guangdong Provincial Hospital of Traditional Chinese Medicine (GPHTCM), Guangzhou, China.
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Hargreaves CE, Rose-Zerilli MJJ, Machado LR, Iriyama C, Hollox EJ, Cragg MS, Strefford JC. Fcγ receptors: genetic variation, function, and disease. Immunol Rev 2015; 268:6-24. [DOI: 10.1111/imr.12341] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Chantal E. Hargreaves
- Cancer Genomics Group; Cancer Sciences; Faculty of Medicine; University of Southampton; Southampton UK
- Antibody and Vaccine Group; Cancer Sciences; Faculty of Medicine; University of Southampton; Southampton UK
| | | | - Lee R. Machado
- Department of Genetics; University of Leicester; Leicester UK
- School of Health; University of Northampton; Northampton UK
| | - Chisako Iriyama
- Department of Hematology and Oncology; Nagoya University Graduate School of Medicine; Nagoya Japan
| | | | - Mark S. Cragg
- Antibody and Vaccine Group; Cancer Sciences; Faculty of Medicine; University of Southampton; Southampton UK
| | - Jonathan C. Strefford
- Cancer Genomics Group; Cancer Sciences; Faculty of Medicine; University of Southampton; Southampton UK
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Rajasekaran N, Oh MR, Kim SS, Kim SE, Kim YD, Choi HJ, Byun B, Shin YK. Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines. J Vis Exp 2015. [PMID: 26484710 DOI: 10.3791/53190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
ddPCR is a highly sensitive PCR method that utilizes a water-oil emulsion system. Using a droplet generator, an extracted nucleic acid sample is partitioned into ~20,000 nano-sized, water-in-oil droplets, and PCR amplification occurs in individual droplets. The ddPCR approach is in identifying sequence mutations, copy number alterations, and select structural rearrangements involving targeted genes. Here, we demonstrate the use of ddPCR as a powerful technique for precisely quantitating rare BRAF V600E mutations in FFPE reference standard cell lines, which is helpful in identifying individuals with cancer. In conclusion, ddPCR technique offers the potential to precisely profile the specific rare mutations in different genes in various types of FFPE samples.
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Affiliation(s)
- Nirmal Rajasekaran
- Research Institute of Pharmaceutical Science, Department of Pharmacy, College of Pharmacy, Seoul National University
| | | | - Sung-Su Kim
- Research Institute of Pharmaceutical Science, Department of Pharmacy, College of Pharmacy, Seoul National University
| | | | | | - Hyun-Jeung Choi
- The Center for Anti-Cancer CDx, N-Bio, Seoul National University
| | - Bohyun Byun
- The Center for Anti-Cancer CDx, N-Bio, Seoul National University
| | - Young Kee Shin
- Research Institute of Pharmaceutical Science, Department of Pharmacy, College of Pharmacy, Seoul National University; The Center for Anti-Cancer CDx, N-Bio, Seoul National University;
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21
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Kit OI, Vodolazhsky DI, Kutilin DS, Gudueva EN. Changes in the number of copies of genetic loci in gastric cancer. Mol Biol 2015. [DOI: 10.1134/s0026893315040093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Di Paolo A, Polillo M, Lastella M, Bocci G, Del Re M, Danesi R. Methods: for studying pharmacogenetic profiles of combination chemotherapeutic drugs. Expert Opin Drug Metab Toxicol 2015; 11:1253-67. [PMID: 26037261 DOI: 10.1517/17425255.2015.1053460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Molecular and genetic analysis of tumors and individuals has led to patient-centered therapies, through the discovery and identification of genetic markers predictive of drug efficacy and tolerability. Present therapies often include a combination of synergic drugs, each of them directed against different targets. Therefore, the pharmacogenetic profiling of tumor masses and patients is becoming a challenge, and several questions may arise when planning a translational study. AREAS COVERED The review presents the different techniques used to stratify oncology patients and to tailor antineoplastic treatments according to individual pharmacogenetic profiling. The advantages of these methodologies are discussed as well as current limits. EXPERT OPINION Facing the rapid technological evolution for genetic analyses, the most pressing issues are the choice of appropriate strategies (i.e., from gene candidate up to next-generation sequencing) and the possibility to replicate study results for their final validation. It is likely that the latter will be the major obstacle in the future. However, the present landscape is opening up new possibilities, overcoming those hurdles that have limited result translation into clinical settings for years.
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Affiliation(s)
- Antonello Di Paolo
- University of Pisa, Department of Clinical and Experimental Medicine, Via Roma 55, 56126 Pisa , Italy +39 050 2218755 ; +39 050 2218758 ;
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Nadauld LD, Garcia S, Natsoulis G, Bell JM, Miotke L, Hopmans ES, Xu H, Pai RK, Palm C, Regan JF, Chen H, Flaherty P, Ootani A, Zhang NR, Ford JM, Kuo CJ, Ji HP. Metastatic tumor evolution and organoid modeling implicate TGFBR2 as a cancer driver in diffuse gastric cancer. Genome Biol 2014; 15:428. [PMID: 25315765 PMCID: PMC4145231 DOI: 10.1186/s13059-014-0428-9] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/27/2014] [Indexed: 12/30/2022] Open
Abstract
Background Gastric cancer is the second-leading cause of global cancer deaths, with metastatic disease representing the primary cause of mortality. To identify candidate drivers involved in oncogenesis and tumor evolution, we conduct an extensive genome sequencing analysis of metastatic progression in a diffuse gastric cancer. This involves a comparison between a primary tumor from a hereditary diffuse gastric cancer syndrome proband and its recurrence as an ovarian metastasis. Results Both the primary tumor and ovarian metastasis have common biallelic loss-of-function of both the CDH1 and TP53 tumor suppressors, indicating a common genetic origin. While the primary tumor exhibits amplification of the Fibroblast growth factor receptor 2 (FGFR2) gene, the metastasis notably lacks FGFR2 amplification but rather possesses unique biallelic alterations of Transforming growth factor-beta receptor 2 (TGFBR2), indicating the divergent in vivo evolution of a TGFBR2-mutant metastatic clonal population in this patient. As TGFBR2 mutations have not previously been functionally validated in gastric cancer, we modeled the metastatic potential of TGFBR2 loss in a murine three-dimensional primary gastric organoid culture. The Tgfbr2 shRNA knockdown within Cdh1-/-; Tp53-/- organoids generates invasion in vitro and robust metastatic tumorigenicity in vivo, confirming Tgfbr2 metastasis suppressor activity. Conclusions We document the metastatic differentiation and genetic heterogeneity of diffuse gastric cancer and reveal the potential metastatic role of TGFBR2 loss-of-function. In support of this study, we apply a murine primary organoid culture method capable of recapitulating in vivo metastatic gastric cancer. Overall, we describe an integrated approach to identify and functionally validate putative cancer drivers involved in metastasis. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0428-9) contains supplementary material, which is available to authorized users.
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Jacobs BKM, Goetghebeur E, Clement L. Impact of variance components on reliability of absolute quantification using digital PCR. BMC Bioinformatics 2014; 15:283. [PMID: 25147026 PMCID: PMC4261249 DOI: 10.1186/1471-2105-15-283] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 08/06/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Digital polymerase chain reaction (dPCR) is an increasingly popular technology for detecting and quantifying target nucleic acids. Its advertised strength is high precision absolute quantification without needing reference curves. The standard data analytic approach follows a seemingly straightforward theoretical framework but ignores sources of variation in the data generating process. These stem from both technical and biological factors, where we distinguish features that are 1) hard-wired in the equipment, 2) user-dependent and 3) provided by manufacturers but may be adapted by the user. The impact of the corresponding variance components on the accuracy and precision of target concentration estimators presented in the literature is studied through simulation. RESULTS We reveal how system-specific technical factors influence accuracy as well as precision of concentration estimates. We find that a well-chosen sample dilution level and modifiable settings such as the fluorescence cut-off for target copy detection have a substantial impact on reliability and can be adapted to the sample analysed in ways that matter. User-dependent technical variation, including pipette inaccuracy and specific sources of sample heterogeneity, leads to a steep increase in uncertainty of estimated concentrations. Users can discover this through replicate experiments and derived variance estimation. Finally, the detection performance can be improved by optimizing the fluorescence intensity cut point as suboptimal thresholds reduce the accuracy of concentration estimates considerably. CONCLUSIONS Like any other technology, dPCR is subject to variation induced by natural perturbations, systematic settings as well as user-dependent protocols. Corresponding uncertainty may be controlled with an adapted experimental design. Our findings point to modifiable key sources of uncertainty that form an important starting point for the development of guidelines on dPCR design and data analysis with correct precision bounds. Besides clever choices of sample dilution levels, experiment-specific tuning of machine settings can greatly improve results. Well-chosen data-driven fluorescence intensity thresholds in particular result in major improvements in target presence detection. We call on manufacturers to provide sufficiently detailed output data that allows users to maximize the potential of the method in their setting and obtain high precision and accuracy for their experiments.
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Affiliation(s)
- Bart K M Jacobs
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Krijgslaan 281, S9, 9000 Ghent, Belgium.
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Su X, Zhan P, Gavine PR, Morgan S, Womack C, Ni X, Shen D, Bang YJ, Im SA, Ho Kim W, Jung EJ, Grabsch HI, Kilgour E. FGFR2 amplification has prognostic significance in gastric cancer: results from a large international multicentre study. Br J Cancer 2014; 110:967-75. [PMID: 24457912 PMCID: PMC3929881 DOI: 10.1038/bjc.2013.802] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 11/05/2013] [Accepted: 12/02/2013] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND In preclinical gastric cancer (GC) models, FGFR2 amplification was associated with increased tumour cell proliferation and survival, and drugs targeting this pathway are now in clinical trials. METHODS FGFR2 FISH was performed on 961 GCs from the United Kingdom, China and Korea, and the relationship with clinicopathological data and overlap with HER2 amplification were analysed. RESULTS The prevalence of FGFR2 amplification was similar between the three cohorts (UK 7.4%, China 4.6% and Korea 4.2%), and intratumoral heterogeneity was observed in 24% of FGFR2 amplified cases. FGFR2 amplification was associated with lymph node metastases (P<0.0001). FGFR2 amplification and polysomy were associated with poor overall survival (OS) in the Korean (OS: 1.83 vs 6.17 years, P=0.0073) and UK (OS: 0.45 vs 1.9 years, P<0.0001) cohorts, and FGFR2 amplification was an independent marker of poor survival in the UK cohort (P=0.0002). Co-amplification of FGFR2 and HER2 was rare, and when high-level amplifications did co-occur these were detected in distinct areas of the tumour. CONCLUSION A similar incidence of FGFR2 amplification was found in Asian and UK GCs and was associated with lymphatic invasion and poor prognosis. This study also shows that HER2 and FGFR2 amplifications are mostly exclusive.
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Affiliation(s)
- X Su
- AstraZeneca Asia & Emerging Markets, Innovative Medicines, Shanghai, China
| | - P Zhan
- AstraZeneca Asia & Emerging Markets, Innovative Medicines, Shanghai, China
| | - P R Gavine
- AstraZeneca Asia & Emerging Markets, Innovative Medicines, Shanghai, China
| | - S Morgan
- AstraZeneca, Oncology Innovative Medicines, Alderley Park, Macclesfield, UK
| | - C Womack
- AstraZeneca, Oncology Innovative Medicines, Alderley Park, Macclesfield, UK
| | - X Ni
- Department of General Surgery, Renji Hospital, School of Medicine, Jiaotong University, Shanghai, China
| | - D Shen
- Department of General Surgery, Renji Hospital, School of Medicine, Jiaotong University, Shanghai, China
| | - Y-J Bang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - S-A Im
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - W Ho Kim
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - E-J Jung
- Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - H I Grabsch
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - E Kilgour
- AstraZeneca, Oncology Innovative Medicines, Alderley Park, Macclesfield, UK
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Abstract
Molecular diagnostics and disease-specific tailored treatments are now being introduced to patients at many hospitals and clinics throughout the world (Strain and Richman, Curr Opin HIV AIDS 8:106-110, 2013) and becoming prevalent in the nonscientific literature. Instead of generically using a "one treatment fits all" approach that may have varying levels of effectiveness to different patients, patient-specific molecular profiling based on the genetic makeup of the disease and/or a more accurate pathogen titer could provide more effective treatments with fewer unwanted side effects. One commonly known example of this scenario is epidermal growth factor receptor (EGFR). EGFR is upregulated in many cancers, including many lung and colorectal cancers. Commonly used treatments for these include the receptor blockers cetuximab or panitumumab and tyrosine kinase inhibitors erlotinib or gefitinib. These agents are effective at reducing out-of-control cell cycling and tumor proliferation, but only if downstream signaling kinases and phosphatases are not mutated. Known oncogenes such as BRAF V600E and KRAS G12/13 that are constitutively activated render these treatments ineffective. The use of known ineffective drugs and treatments can thus be avoided reducing time to more effective treatments, reducing cost, and increasing patient well-being. Although digital PCR is for all practical purposes a "new" technology, there is already tremendous interest in its potential for the clinical diagnostics arena. Specificity of the information acquired, accuracy of results, time to results, and cost per sample analyzed are making dPCR an attractive tool for this field. Three areas where dPCR will have a noticeable impact are pathogen/viral detection and quantitation, copy number variations, and rare mutation detection and abundance, but it will inevitably expand from these as the technology becomes more and more prevalent. This chapter discusses digital PCR assay optimization and validation, pathogen/viral detection and quantitation, copy number variation, and rare mutation abundance assays. The sample methods described below utilize the QX100/QX200 methodologies, but with the exception of reaction sub-partitioning (dependent on the instrumentation used) most other parameters remain the same.
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Affiliation(s)
- Francisco Bizouarn
- Gene Expression Division, Bio-Rad Laboratories, 2000 Alfred Nobel Dr., Hercules, CA, 94547, USA,
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Abstract
Digital PCR (dPCR) is a molecular biology technique going through a renaissance. With the arrival of new instrumentation dPCR can now be performed as a routine molecular biology assay. This exciting new technique provides quantitative and detection capabilities that by far surpass other methods currently used. This chapter is an overview of some of the applications currently being performed using dPCR as well as the fundamental concepts and techniques this technology is based on.
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Affiliation(s)
- Francisco Bizouarn
- Gene Expression Division, Bio-Rad Laboratories, 2000 Alfred Nobel Dr., Hercules, CA, 94547, USA,
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Nadauld LD, Ford JM. Molecular profiling of gastric cancer: toward personalized cancer medicine. J Clin Oncol 2013; 31:838-9. [PMID: 23341521 DOI: 10.1200/jco.2012.47.1714] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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