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Echeverria CV, Leathers TA, Rogers CD. Comparative analysis of fixation techniques for signal detection in avian embryos. Dev Biol 2024; 517:13-23. [PMID: 39245159 DOI: 10.1016/j.ydbio.2024.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 08/22/2024] [Accepted: 09/05/2024] [Indexed: 09/10/2024]
Abstract
The choice of fixation method significantly impacts tissue morphology and visualization of gene expression and proteins after in situ hybridization chain reaction (HCR) or immunohistochemistry (IHC), respectively. In this study, we compared the effects of paraformaldehyde (PFA) and trichloroacetic acid (TCA) fixation techniques prior to HCR and IHC on chicken embryos. Our findings underscore the importance of optimizing fixation methods for accurate visualization and subsequent interpretation of HCR and IHC results, with implications for probe and antibody validation and tissue-specific protein localization studies. We found that TCA fixation resulted in larger and more circular nuclei and neural tubes compared to PFA fixation. Additionally, TCA fixation altered the subcellular fluorescence signal intensity of various proteins, including transcription factors, cytoskeletal proteins, and cadherins. Notably, TCA fixation revealed protein signals in tissues that may be inaccessible with PFA fixation. In contrast, TCA fixation proved ineffective for mRNA visualization. These results highlight the need for optimization of fixation protocols depending on the target and model system, emphasizing the importance of methodological considerations in biological analyses.
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Affiliation(s)
- Camilo V Echeverria
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA
| | - Tess A Leathers
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA
| | - Crystal D Rogers
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA.
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2
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Diamantino GML, Beeler-Marfisi J, Foster RA, Sears W, Defarges A, Vernau W, Bienzle D. Effects of fixation and demineralization on histomorphology and DNA amplification of canine bone marrow. Vet Pathol 2024:3009858241257920. [PMID: 38842072 DOI: 10.1177/03009858241257920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Fixation and demineralization protocols for bone marrow (BM) across diagnostic laboratories are not standardized. How different protocols affect histomorphology and DNA amplification is incompletely understood. In this study, 2 fixatives and 3 demineralization methods were tested on canine BM samples. Twenty replicate sternal samples obtained within 24 hours of death were fixed overnight in either acetic acid-zinc-formalin (AZF) or 10% neutral-buffered formalin (NBF) and demineralized with formic acid for 12 hours. Another 53 samples were fixed in AZF and demineralized with hydrochloric acid for 1-hour, formic acid for 12 hours, or ethylenediamine tetraacetic acid (EDTA) for 24 hours. Histologic sections were scored by 4 raters as of insufficient, marginal, good, or excellent quality. In addition, DNA samples extracted from sections treated with the different fixation and demineralization methods were amplified with 3 sets of primers to conserved regions of T cell receptor gamma and immunoglobulin heavy chain genes. Amplification efficiency was graded based on review of capillary electrophoretograms. There was no significant difference in the histomorphology scores of sections fixed in AZF or NBF. However, EDTA-based demineralization yielded higher histomorphology scores than demineralization with hydrochloric or formic acid, whereas formic acid resulted in higher scores than hydrochloric acid. Demineralization with EDTA yielded DNA amplification in 29 of 36 (81%) samples, whereas demineralization with either acid yielded amplification in only 2 of 72 (3%) samples. Although slightly more time-consuming and labor-intensive, tissue demineralization with EDTA results in superior morphology and is critical for polymerase chain reaction (PCR) amplification with the DNA extraction method described in this article.
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Kim MC, Kwon SY, Jung HR, Bae YK. Impact of immunohistochemistry staining conditions on the incidence of human epidermal growth factor receptor 2 (HER2)-low breast cancer. Virchows Arch 2024:10.1007/s00428-024-03824-6. [PMID: 38758231 DOI: 10.1007/s00428-024-03824-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/12/2024] [Accepted: 05/09/2024] [Indexed: 05/18/2024]
Abstract
We investigated frequencies of HER2-low breast cancer (BC) (immunohistochemistry [IHC] 1+ or 2+ without gene amplification) before and after IHC conditions were modified in order to understand the impact of IHC staining conditions on frequencies of HER2-low BC. Primary BC cases diagnosed at the Yeungnam University Hospital (YUH, n = 728) or Keimyung University Dongsan Hospital (KUDH, n = 290) in 2022 were reviewed, and data on HER2 status and IHC conditions were collected (cohort 1). Both institutions used the 4B5 antibody for HER2 IHC but had different staining protocols. After modifications of the IHC conditions at both institutions, primary BC cases (YUH, n = 324 and KUDH, n = 135) diagnosed from April to July 2023 (cohort 2) were reviewed to assess any changes in the frequency of HER2 status. In cohort 1, of the 728 cases diagnosed at YUH, 556 (76.4%) were HER2-zero, 76 (10.4%) were HER2-low, and 96 (13.2%) were HER2-positive, and of the 290 cases diagnosed at KUDH, 135 (46.6%) were HER2-zero, 82 (28.3%) were HER2-low, and 73 (25.2%) were HER2-positive. Modifications in HER2 IHC staining conditions dramatically increased the frequencies of HER2-low BC in cohort 2 (YUH 38.9% and KUDH 49.6%), but they did not result in significant changes in the HER2-positive rates (YUH 15.4% and KUDH 25.2%) compared to cohort 1. In conclusion, minor modifications in HER2 IHC staining conditions significantly affected the frequency of HER2-low BC but had little impact on the HER2-positivity rate. Each pathology laboratory should verify IHC conditions using control slides (including 1+) to enable the accurate identification of HER2-low BC.
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Affiliation(s)
- Min Chong Kim
- Department of Pathology, Yeungnam University College of Medicine, Daegu, Republic of Korea
| | - Sun Young Kwon
- Department of Pathology, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - Hye Ra Jung
- Department of Pathology, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - Young Kyung Bae
- Department of Pathology, Yeungnam University College of Medicine, Daegu, Republic of Korea.
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4
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Frigon EM, Gérin-Lajoie A, Dadar M, Boire D, Maranzano J. Comparison of histological procedures and antigenicity of human post-mortem brains fixed with solutions used in gross anatomy laboratories. Front Neuroanat 2024; 18:1372953. [PMID: 38659652 PMCID: PMC11039794 DOI: 10.3389/fnana.2024.1372953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/01/2024] [Indexed: 04/26/2024] Open
Abstract
Background Brain banks provide small tissue samples to researchers, while gross anatomy laboratories could provide larger samples, including complete brains to neuroscientists. However, they are preserved with solutions appropriate for gross-dissection, different from the classic neutral-buffered formalin (NBF) used in brain banks. Our previous work in mice showed that two gross-anatomy laboratory solutions, a saturated-salt-solution (SSS) and an alcohol-formaldehyde-solution (AFS), preserve antigenicity of the main cellular markers (neurons, astrocytes, microglia, and myelin). Our goal is now to compare the quality of histology and antigenicity preservation of human brains fixed with NBF by immersion (practice of brain banks) vs. those fixed with a SSS and an AFS by whole body perfusion, practice of gross-anatomy laboratories. Methods We used a convenience sample of 42 brains (31 males, 11 females; 25-90 years old) fixed with NBF (N = 12), SSS (N = 13), and AFS (N = 17). One cm3 tissue blocks were cut, cryoprotected, frozen and sliced into 40 μm sections. The four cell populations were labeled using immunohistochemistry (Neurons = neuronal-nuclei = NeuN, astrocytes = glial-fibrillary-acidic-protein = GFAP, microglia = ionized-calcium-binding-adaptor-molecule1 = Iba1 and oligodendrocytes = myelin-proteolipid-protein = PLP). We qualitatively assessed antigenicity and cell distribution, and compared the ease of manipulation of the sections, the microscopic tissue quality, and the quality of common histochemical stains (e.g., Cresyl violet, Luxol fast blue, etc.) across solutions. Results Sections of SSS-fixed brains were more difficult to manipulate and showed poorer tissue quality than those from brains fixed with the other solutions. The four antigens were preserved, and cell labeling was more often homogeneous in AFS-fixed specimens. NeuN and GFAP were not always present in NBF and SSS samples. Some antigens were heterogeneously distributed in some specimens, independently of the fixative, but an antigen retrieval protocol successfully recovered them. Finally, the histochemical stains were of sufficient quality regardless of the fixative, although neurons were more often paler in SSS-fixed specimens. Conclusion Antigenicity was preserved in human brains fixed with solutions used in human gross-anatomy (albeit the poorer quality of SSS-fixed specimens). For some specific variables, histology quality was superior in AFS-fixed brains. Furthermore, we show the feasibility of frequently used histochemical stains. These results are promising for neuroscientists interested in using brain specimens from anatomy laboratories.
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Affiliation(s)
- Eve-Marie Frigon
- Department of Anatomy, University of Quebec in Trois-Rivieres, Trois-Rivieres, QC, Canada
| | - Amy Gérin-Lajoie
- Department of Anatomy, University of Quebec in Trois-Rivieres, Trois-Rivieres, QC, Canada
| | - Mahsa Dadar
- Department of Psychiatry, Douglas Research Center, McGill University, Montreal, QC, Canada
| | - Denis Boire
- Department of Anatomy, University of Quebec in Trois-Rivieres, Trois-Rivieres, QC, Canada
| | - Josefina Maranzano
- Department of Anatomy, University of Quebec in Trois-Rivieres, Trois-Rivieres, QC, Canada
- Department of Neurology and Neurosurgery, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Echeverria CV, Leathers TA, Rogers CD. Effectiveness of fixation methods for wholemount immunohistochemistry across cellular compartments in chick embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.23.586361. [PMID: 38585750 PMCID: PMC10996528 DOI: 10.1101/2024.03.23.586361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The choice of fixation method significantly impacts tissue morphology and protein visualization after immunohistochemistry (IHC). In this study, we compared the effects of paraformaldehyde (PFA) and trichloroacetic acid (TCA) fixation prior to IHC on chicken embryos. Our findings underscore the importance of validating fixation methods for accurate interpretation of IHC results, with implications for antibody validation and tissue-specific protein localization studies. We found that TCA fixation resulted in larger and more circular nuclei compared to PFA fixation. Additionally, TCA fixation altered the appearance of subcellular localization and fluorescence intensity of various proteins, including transcription factors and cytoskeletal proteins. Notably, TCA fixation revealed protein localization domains that may be inaccessible with PFA fixation. These results highlight the need for optimization of fixation protocols depending on the target epitope and model system, emphasizing the importance of methodological considerations in biological analyses.
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Affiliation(s)
- Camilo V Echeverria
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA
| | - Tess A Leathers
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA
| | - Crystal D Rogers
- Department of Anatomy, Physiology, and Cell Biology, University of California, Davis, Davis, CA, USA
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Yeo YY, Cramer P, Deisher A, Bai Y, Zhu B, Yeo WJ, Shipp MA, Rodig SJ, Jiang S. A Hitchhiker's guide to high-dimensional tissue imaging with multiplexed ion beam imaging. Methods Cell Biol 2024; 186:213-231. [PMID: 38705600 PMCID: PMC11244641 DOI: 10.1016/bs.mcb.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Advancements in multiplexed tissue imaging technologies are vital in shaping our understanding of tissue microenvironmental influences in disease contexts. These technologies now allow us to relate the phenotype of individual cells to their higher-order roles in tissue organization and function. Multiplexed Ion Beam Imaging (MIBI) is one of such technologies, which uses metal isotope-labeled antibodies and secondary ion mass spectrometry (SIMS) to image more than 40 protein markers simultaneously within a single tissue section. Here, we describe an optimized MIBI workflow for high-plex analysis of Formalin-Fixed Paraffin-Embedded (FFPE) tissues following antigen retrieval, metal isotope-conjugated antibody staining, imaging using the MIBI instrument, and subsequent data processing and analysis. While this workflow is focused on imaging human FFPE samples using the MIBI, this workflow can be easily extended to model systems, biological questions, and multiplexed imaging modalities.
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Affiliation(s)
- Yao Yu Yeo
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA, United States
| | - Precious Cramer
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Addison Deisher
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Yunhao Bai
- Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, United States
| | - Bokai Zhu
- Department of Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, United States
| | - Wan-Jin Yeo
- Department of Physics, Institute of Learning and Brain Sciences, University of Washington, Seattle, WA, United States
| | - Margaret A Shipp
- Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, United States
| | - Scott J Rodig
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Sizun Jiang
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; Program in Virology, Division of Medical Sciences, Harvard Medical School, Boston, MA, United States; Department of Pathology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, United States; Broad Institute of MIT and Harvard, Cambridge, MA, United States.
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7
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Meier Bürgisser G, Heuberger DM, Rieber J, Miescher I, Giovanoli P, Calcagni M, Buschmann J. Delineation of the healthy rabbit tongue by immunohistochemistry - A technical note. Acta Histochem 2024; 126:152127. [PMID: 38039795 DOI: 10.1016/j.acthis.2023.152127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 11/23/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023]
Abstract
In the oral cavity the tongue is an important muscular organ that supports the swallowing of food and liquids. It is responsible for the sense of taste, based on the many different taste buds it contains. Research in the field of tongue diseases demands for suitable preclinical models. The healthy rabbit tongue may therefore serve as baseline and reference for the pathological situation. With this consideration, we covered the fixation and histological stainings as well as the immunohistochemical labelling of the healthy rabbit tongue. In this technical note, initial choice of the fixative is discussed, with a comparison of formalin fixation and subsequent paraffin embedding versus cryopreservation. Moreover, we delineate the effect of an antigen retrieval step for formalin fixation by several examples. Finally, we provide ECM markers collagen I, collagen III, fibronectin, α-SMA and elastin staining as well as ki67 for proliferative status and PAR-2 protein expression as a marker for inflammatory status and nociception in tongue sections, mainly from the tongue body. Technically, we found superiority of paraffin sections for collagen I, collagen III, fibronectin, ki67 and α-SMA labelling, for selected detections systems. As for ECM components, the lamina propria was very rich in collagen and fibronectin, while the muscular body of the tongue showed only collagen and fibronectin positive areas between the muscle fibers. Moreover, α-SMA was clearly expressed in the walls of arteries and veins. The inflammatory marker PAR-2 on the other hand was prominently expressed in the salivary glands and to some extent in the walls of the vessels. Particular PAR-2 expression was found in the excretory ducts of the tongue. This technical note has the aim to provide baseline images that can be used to compare the pathological state of the diseased rabbit tongue as well as for inter-species comparison, such as mouse or rat tongue. Finally, it can be used for the comparison with the human situation.
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Affiliation(s)
- Gabriella Meier Bürgisser
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Dorothea M Heuberger
- Institute of Intensive Care Medicine, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Julia Rieber
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Iris Miescher
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Pietro Giovanoli
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Maurizio Calcagni
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Johanna Buschmann
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland.
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8
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Önen S, Gizer M, Korkusuz P. Flow Cytometric and Immunohistochemical Follow-Up of Spermatogonial Lineage Commitment. Methods Mol Biol 2024; 2849:239-251. [PMID: 37801256 DOI: 10.1007/7651_2023_506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Flow cytometry and immunohistochemistry techniques both determine the target protein by immunolabeling. Flow cytometric analysis quantifies total number of fluorescent labeled cells and qualify sup-populations according to size and granularity. Immunohistochemistry is able to map immune-labeled cells and extracellular matrix components under light and electron microscope by enzyme or fluorescent molecules. Real-time identification, in-time classification, and final plotting of spermatogonial lineage are of crucial importance for monitoring the fertility potential of spermatogonial stem cell microenvironment and predicting progress of spermatogenesis. Here we define the evaluation of mouse male germ cell microenvironment at single cell and whole tissue section levels by using flow cytometric and immunohistochemical approaches.
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Affiliation(s)
| | - Merve Gizer
- METU MEMS Center, Ankara, Turkey
- Department of Stem Cell Sciences, Graduate School of Health Sciences, Hacettepe University, Ankara, Turkey
| | - Petek Korkusuz
- METU MEMS Center, Ankara, Turkey.
- Department of Histology and Embryology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
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Grillo F, Ali M, Paudice M, Pigozzi S, Anselmi G, Scabini S, Sciallero S, Piol N, Mastracci L. Impact of formalin fixation on mismatch repair protein evaluation by immunohistochemistry. Virchows Arch 2023; 483:677-685. [PMID: 37773452 PMCID: PMC10673985 DOI: 10.1007/s00428-023-03661-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/29/2023] [Accepted: 09/15/2023] [Indexed: 10/01/2023]
Abstract
Mismatch repair/microsatellite instability (MMR/MSI) status in colorectal cancer (CRC) has become fundamental as a diagnostic, prognostic, and predictive factor. MMR immunohistochemistry (IHC) is considered a simple and reliable approach; however, its effectiveness depends on pre-analytic factors. Aim of this study was to investigate the impact of different fixation times/protocols on MMR protein IHC quality. Left over tissue from surgically resected CRC samples (cold ischemia time < 30 min) where fixed as follows: standard formalin fixation (24-48 h); hypo-fixation (<20 h); hyper-fixation (>90 h); cold (4°C) fixation (24-48 h); standard fixation for small sample size (0.5×0.5 cm). Samples for each group were collected from 30 resected CRC and the following parameters were evaluated on 600 immunohistochemical stains: intensity of expression; patchiness of staining; presence of central artefact. Forty-six immunoreactions were inadequate (score 0 intensity), the majority regarding MLH1 or PMS2 in the hypo-fixation group (47.8%), followed by the hyper-fixation group (28.1%); cold formalin fixation showed the least inadequate cases. Patchiness and central artefact were more frequent in hypo-fixation and standard fixation group compared to the others. MLH1 (closely followed by PMS2) performed worse with regard to immunostaining intensity (p=0.0002) in the standard and in the hypo-fixation group (p< 0.00001). Using a small sample size improved patchiness/central artefacts. This is the first study specifically created to evaluate the impact of fixation on MMR protein IHC, showing that both formalin hypo- and hyper-fixation can cause problems; 24-h formalin fixation as well as cold (4°C) formalin fixation are recommended for successful IHC MMR evaluation.
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Affiliation(s)
- Federica Grillo
- Pathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
- Pathology Unit, Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
| | - Murad Ali
- Pathology Unit, Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Michele Paudice
- Pathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
- Pathology Unit, Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Simona Pigozzi
- Pathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
- Pathology Unit, Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Giorgia Anselmi
- Molecular Diagnostic Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Stefano Scabini
- Oncological Surgical Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Stefania Sciallero
- Medical Oncology Unit 1, IRCCS Ospedale Policlinico San Martino, 16132, Genoa, Italy
| | - Nataniele Piol
- Pathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Luca Mastracci
- Pathology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
- Pathology Unit, Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa and IRCCS Ospedale Policlinico San Martino, Genoa, Italy
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10
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Meier Bürgisser G, Heuberger DM, Giovanoli P, Calcagni M, Buschmann J. Delineation of the healthy rabbit tonsil by immunohistochemistry - A short communication. Acta Histochem 2023; 125:152098. [PMID: 37804548 DOI: 10.1016/j.acthis.2023.152098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 10/09/2023]
Abstract
Situated in the oral cavity, the rabbit palatine tonsils are part of the mucosal immune system and help to defend the body against foreign pathogens. Expressed as two oval protrusions in the wall of the oropharynx, the rabbit palatine tonsils are characterized by excretory ducts and trabeculae. We here compare paraffin embedded and cryosections of the healthy rabbit tonsils. This analysis centers on evaluating the differential outcomes resulting from the application of these fixation methodologies in conjunction with immunohistochemical assays targeting collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and ki67. Subsequent recommendations are provided based on our findings. Furthermore, we demonstrate the advantage of an antigen retrieval step in immunohistochemical labeling of paraffin sections. Basic classical histological stainings as HE, GT and elastin were also performed. Comparison of different stainings and labelings was furthermore performed in serial sections, showing that adjacent to the excretory ducts, the tonsillar tissue was particularly composed of collagen I and fibronectin, while the vessel walls were predominantly α-SMA positive. Moreover, PAR-2 immunohistochemical staining was performed, where a small fraction of the cells found in the tonsillar connective tissue were PAR-2 positive (probably a subpopulation of mast cells), as well as the lumen of some excretory ducts and trabeculae. Collagen III on the other hand was only weakly expressed in the tonsils. Proliferating ki67 positive cells were rare. This endeavor serves to furnish the scientific community with reference imagery pertinent to researchers opting for the rabbit palatine tonsil model. The diversity of staining techniques employed herein establishes a foundational repository of images, primed for comparative analysis against pathological conditions. Furthermore, these images hold the potential to illustrate inter-species variations. For instance, they can be juxtaposed against murine or rodent tonsils, or even offer insights into the human context.
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Affiliation(s)
- Gabriella Meier Bürgisser
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Dorothea M Heuberger
- Institute of Intensive Care Medicine, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Pietro Giovanoli
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Maurizio Calcagni
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Johanna Buschmann
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland.
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11
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Lawson NL, Scorer PW, Williams GH, Vandenberghe ME, Ratcliffe MJ, Barker C. Impact of Decalcification, Cold Ischemia, and Deglycosylation on Performance of Programmed Cell Death Ligand-1 Antibodies With Different Binding Epitopes: Comparison of 7 Clones. Mod Pathol 2023; 36:100220. [PMID: 37230414 DOI: 10.1016/j.modpat.2023.100220] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 05/27/2023]
Abstract
Programmed cell death ligand-1 (PD-L1) expression levels in patients' tumors have demonstrated clinical utility across many cancer types and are used to determine treatment eligibility. Several independently developed PD-L1 immunohistochemical (IHC) predictive assays are commercially available and have demonstrated different levels of staining between assays, generating interest in understanding the similarities and differences between assays. Previously, we identified epitopes in the internal and external domains of PD-L1, bound by antibodies in routine clinical use (SP263, SP142, 22C3, and 28-8). Variance in performance of assays utilizing these antibodies, observed following exposure to preanalytical factors such as decalcification, cold ischemia, and duration of fixation, encouraged additional investigation of antibody-binding sites, to understand whether binding site structures/conformations contribute to differential PD-L1 IHC assay staining. We proceeded to further investigate the epitopes on PD-L1 bound by these antibodies, alongside the major clones utilized in laboratory-developed tests (E1L3N, QR1, and 73-10). Characterization of QR1 and 73-10 clones demonstrated that both bind the PD-L1 C-terminal internal domain, similar to SP263/SP142. Our results also demonstrate that under suboptimal decalcification or fixation conditions, the performance of internal domain antibodies is less detrimentally affected than that of external domain antibodies 22C3/28-8. Furthermore, we show that the binding sites of external domain antibodies are susceptible to deglycosylation and conformational structural changes, which directly result in IHC staining reduction or loss. The binding sites of internal domain antibodies were unaffected by deglycosylation or conformational structural change. This study demonstrates that the location and conformation of binding sites, recognized by antibodies employed in PD-L1 diagnostic assays, differ significantly and exhibit differing degrees of robustness. These findings should reinforce the need for vigilance when performing clinical testing with different PD-L1 IHC assays, particularly in the control of cold ischemia and the selection of fixation and decalcification conditions.
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Affiliation(s)
- Nicola L Lawson
- Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Cambridge, United Kingdom; Biologics Engineering, Oncology R&D, AstraZeneca, Cambridge, United Kingdom.
| | - Paul W Scorer
- Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
| | | | - Michel E Vandenberghe
- Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
| | - Marianne J Ratcliffe
- Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
| | - Craig Barker
- Precision Medicine and Biosamples, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
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12
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Ruddenklau A, Glendining K, Prescott M, Campbell RE. Validation of a new Custom Polyclonal Progesterone Receptor Antibody for Immunohistochemistry in the Female Mouse Brain. J Endocr Soc 2023; 7:bvad113. [PMID: 37693686 PMCID: PMC10492226 DOI: 10.1210/jendso/bvad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Indexed: 09/12/2023] Open
Abstract
Immunohistochemical visualization of progesterone receptor (PR)-expressing cells in the brain is a powerful technique to investigate the role of progesterone in the neuroendocrine regulation of fertility. A major obstacle to the immunohistochemical visualization of progesterone-sensitive cells in the rodent brain has been the discontinuation of the commercially produced A0098 rabbit polyclonal PR antibody by DAKO. To address the unavailability of this widely used PR antibody, we optimized and evaluated 4 alternative commercial PR antibodies and found that each lacked the specificity and/or sensitivity to immunohistochemically label PR-expressing cells in paraformaldehyde-fixed female mouse brain sections. As a result, we developed and validated a new custom RC269 PR antibody, directed against the same 533-547 amino acid sequence of the human PR as the discontinued A0098 DAKO PR antibody. Immunohistochemical application of the RC269 PR antibody on paraformaldehyde-fixed mouse brain sections resulted in nuclear PR labeling that was highly distinguishable from background, specific to its antigen, highly regulated by estradiol, matched the known distribution of PR protein expression in the female mouse hypothalamus, and nearly identical to that of the discontinued A0098 DAKO PR antibody. In summary, the RC269 PR antibody is a specific and sensitive antibody to immunohistochemically visualize PR-expressing cells in the mouse brain.
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Affiliation(s)
- Amy Ruddenklau
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Kelly Glendining
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Melanie Prescott
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Rebecca E Campbell
- Centre for Neuroendocrinology and Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
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13
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Abuja PM, Pabst D, Bourgeois B, Loibner M, Ulz C, Kufferath I, Fackelmann U, Stumptner C, Kraemer R, Madl T, Zatloukal K. Residual Humidity in Paraffin-Embedded Tissue Reduces Nucleic Acid Stability. Int J Mol Sci 2023; 24:8010. [PMID: 37175716 PMCID: PMC10178321 DOI: 10.3390/ijms24098010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/11/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Molecular diagnostics in healthcare relies increasingly on genomic and transcriptomic methodologies and requires appropriate tissue specimens from which nucleic acids (NA) of sufficiently high quality can be obtained. Besides the duration of ischemia and fixation type, NA quality depends on a variety of other pre-analytical parameters, such as storage conditions and duration. It has been discussed that the improper dehydration of tissue during processing influences the quality of NAs and the shelf life of fixed tissue. Here, we report on establishing a method for determining the amount of residual water in fixed, paraffin-embedded tissue (fixed by neutral buffered formalin or a non-crosslinking fixative) and its correlation to the performance of NAs in quantitative real-time polymerase chain reaction (qRT-PCR) analyses. The amount of residual water depended primarily on the fixative type and the dehydration protocol and, to a lesser extent, on storage conditions and time. Moreover, we found that these parameters were associated with the qRT-PCR performance of extracted NAs. Besides the cross-linking of NAs and the modification of nucleobases by formalin, the hydrolysis of NAs by residual water was found to contribute to reduced qRT-PCR performance. The negative effects of residual water on NA stability are not only important for the design and interpretation of research but must also be taken into account in clinical diagnostics where the reanalysis of archived tissue from a primary tumor may be required (e.g., after disease recurrence). We conclude that improving the shelf life of fixed tissue requires meticulous dehydration and dry storage to minimize the degradative influence of residual water on NAs.
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Affiliation(s)
- Peter M. Abuja
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Daniela Pabst
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Benjamin Bourgeois
- Gottfried Schatz Research Centre for Cell Signalling, Metabolism and Ageing, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Martina Loibner
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Christine Ulz
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Iris Kufferath
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Ulrike Fackelmann
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Cornelia Stumptner
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Rainer Kraemer
- Berghof Products & Instruments GmbH, 72800 Eningen, Germany
| | - Tobias Madl
- Gottfried Schatz Research Centre for Cell Signalling, Metabolism and Ageing, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Kurt Zatloukal
- Diagnostic & Research Centre for Molecular Biomedicine, Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
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14
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Bürgisser GM, Heuberger DM, Schaffner N, Giovanoli P, Calcagni M, Buschmann J. Delineation of the healthy rabbit heart by immunohistochemistry - A technical note. Acta Histochem 2023; 125:151993. [PMID: 36584538 DOI: 10.1016/j.acthis.2022.151993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/22/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022]
Abstract
Heart failure poses a big health problem and may result from obesity, smoking, alcohol and/or growing age. Studying pathological heart tissue demands accurate histological and immunohistochemical stainings in animal models, including chromogenic and fluorescent approaches. Moreover, a reliable set of healthy heart stainings and labeling are required, in order to provide a reference for the pathological situation. Heart and brain tissue of a healthy rabbit were collected, and different histological key steps were compared, such as paraffin embedding after formalin fixation versus cryopreservation; an antigen retrieval (AR) step in processing paraffin sections versus the same procedure without AR; or a chromogenic with a fluorescent detection system, respectively. Using serial sections, we stained the same morphological structure with classic approaches (HE, Masson Goldner Trichrome (GT) and Elastica van Gieson (EL)) and with different markers, including collagen I, collagen III, fibronectin, α-SMA, protease-activated receptor-2 (PAR-2) which is an inflammation-related marker, and ki67 for proliferating cells. Differences between conditions were quantitatively assessed by measuring the color intensity. Generally, cryosections exhibited a more prominent signal intensity in immunohistochemically labeled sections than in paraffin sections, but the strong staining was slurry, which sometimes impeded proper identification of morphological structures, particularly at higher magnifications. In addition, the advantage of an AR step was observed when compared to the condition without AR, where signal intensities were significantly lower. Different stainings of the heart arteries and the myocardium revealed a clear distribution of extracellular matrix components, with prominent collagen III in the artery wall, but an absence of collagen III in the myocardium. Moreover, paraffin-embedded sections provided more distinct structures compared to cryosections after collagen III, ki67, fibronectin, and α-SMA labeling. As for the Purkinje cells that were depicted in the heart and the cerebellum (Purkinje neurons), we found GT staining most suitable to depict them in the heart, while HE as well as EL staining was ideal to depict Purkinje neurons in the cerebellum. In sum, we provide useful reference images with different stainings for researchers using the rabbit heart or brain model. Such images can help to decide which of the immunohistochemical protocols are valuable to reach a specific aim. Recommendations are given for the best visualization of the target structures and specific (immunohistochemical) staining.
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Affiliation(s)
- Gabriella Meier Bürgisser
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Dorothea M Heuberger
- Institute of Intensive Care Medicine, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Nicola Schaffner
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Pietro Giovanoli
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Maurizio Calcagni
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Johanna Buschmann
- Division of Plastic Surgery and Hand Surgery, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland.
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15
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Wilburn D, Fletcher E, Ismaeel A, Miserlis D, Zechmann B, Koutakis P. Chemical and cryo-collection of muscle samples for transmission electron microscopy using Methacarn and dimethyl sulfoxide ✰. Ultramicroscopy 2022; 241:113600. [PMID: 35988477 PMCID: PMC9511158 DOI: 10.1016/j.ultramic.2022.113600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/08/2022] [Accepted: 08/10/2022] [Indexed: 01/24/2023]
Abstract
Muscle samples are commonly chemically fixed or frozen immediately upon collection for biochemical and morphological analysis. Certain fixatives such as glutaraldehyde and osmium tetroxide are widely used for transmission electron microscopy (TEM) and lead to adequate preservation of muscle ultrastructure, but do not preserve the molecular features of samples. Methacarn is suggested to be a preferable chemical fixative for light microscopy because it maintains immunohistological features of samples. However, the efficacy of methacarn to preserve ultrastructural features as a primary chemical fixative for TEM is currently unclear. Additionally, cryo-preservation of samples for TEM analysis involves freezing processes such as plunge freezing, slam freezing, or high pressure freezing. High pressure freezing is the considered the gold standard but requires costly equipment and may not be a viable option for many labs collecting tissue samples from remote locations. Dimethyl sulfoxide (DMSO) is a commonly used cryoprotectant that may allow for better structural preservation of samples by impairing ice damage that occurs during plunge/snap freezing. We aimed to assess the effectiveness of methacarn as a primary chemical fixative and determine the effect of pre-coating samples with DMSO before plunge/snap freezing tissues to be prepared for TEM. The micrographs of the methcarn-fixed samples indicate a loss of Z-disk integrity, intermyofibrillar space, mitochondria structure, and lipids. Ultimately, methacarn is not a viable primary fixative for tissue sample preparation for TEM. Similarly, liquid nitrogen freezing of samples wrapped in aluminum foil produced non-uniform Z-disk alignments that appeared smeared with swollen mitochondria. DMSO coating before freezing appears to lessen the alterations to contractile and mitochondrial morphological structures. DMSO appears to be useful for preserving the ultrastructure of sarcomeres if samples are covered before freezing.
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Affiliation(s)
- Dylan Wilburn
- Department of Health, Human Performance, and Recreation, Baylor University, 254-710-2911, B.207 Baylor Science Building, One Bear Place #97388, 76798-7388, Waco, TX 76706, USA
| | - Emma Fletcher
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | - Ahmed Ismaeel
- Department of Biology, Baylor University, Waco, TX 76706, USA
| | - Dimitrios Miserlis
- Department of Surgery, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Bernd Zechmann
- Department of Biology, Baylor University, Waco, TX 76706, USA; Center for Microscopy and Imaging, Baylor University, Waco, Texas 76706, USA
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16
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Mizutani Y, Shiogama K, Inada KI, Takeuchi T, Niimi A, Suzuki M, Tsutsumi Y. Enzyme-labeled Antigen Method: Factors Influencing the Deterioration of Antigen-binding Activity of Specific Antibodies during Formalin Fixation and Paraffin Embedding. Acta Histochem Cytochem 2022; 55:129-148. [DOI: 10.1267/ahc.22-00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 08/23/2022] [Indexed: 11/22/2022] Open
Affiliation(s)
- Yasuyoshi Mizutani
- Department of Molecular Oncology, Fujita Health University School of Medicine
| | - Kazuya Shiogama
- Department of Morphology and Pathological Diagnosis, Fujita Health University School of Medical Sciences
| | - Ken-ichi Inada
- Department of Diagnostic Pathology, Fujita Health University School of Medicine
| | - Toshiyuki Takeuchi
- Department of Molecular Oncology, Fujita Health University School of Medicine
| | - Atsuko Niimi
- Department of Molecular Oncology, Fujita Health University School of Medicine
| | - Motoshi Suzuki
- Department of Molecular Oncology, Fujita Health University School of Medicine
| | - Yutaka Tsutsumi
- Diagnostic Pathology Clinic, Pathos Tsutsumi (Tsutusmi Byori Shindanka Clinic)
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17
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Mukherjee A, Ghosh S, Biswas D, Rao A, Shetty P, Epari S, Moiyadi A, Srivastava S. Clinical Proteomics for Meningioma: An Integrated Workflow for Quantitative Proteomics and Biomarker Validation in Formalin-Fixed Paraffin-Embedded Tissue Samples. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2022; 26:512-520. [PMID: 36036964 DOI: 10.1089/omi.2022.0082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Clinical proteomics is a rapidly emerging frontier in laboratory medicine. High-throughput proteomic investigations of biopsy tissues provide mechanistic insights into complex human diseases. For large-scale proteomics, formalin-fixed and paraffin-embedded (FFPE) tissue samples offer a viable alternative to fresh-frozen (FF) tissues that have restricted availability. In this context, meningioma is one of the most common primary brain tumors where innovation in diagnostics and therapeutic targets can benefit from clinical proteomics. We present here an integrated workflow for quantitative proteomics and biomarker validation of meningioma FFPE tissues. Applying label-free quantitative (LFQ) proteomics, we reproducibly (Pearson's correlation: 0.84-0.91) obtained an in-depth proteome coverage (nearly 4000 proteins per sample) from 120 min gradient of single unfractionated mass spectrometry run. Furthermore, building upon LFQ data and literature curated set of meningioma-associated proteins, we validated VIM, AHNAK, and CLU from FFPE tissues using selected reaction monitoring (SRM) assay and compared its performance with FF tissues. This study illustrates how knowledge from label-free proteomics can be integrated for selecting peptides for targeted validation and suggests that FFPE tissues are comparable to FF tissues for SRM assays. This quantitative clinical proteomics workflow is scalable for large-scale clinical diagnostics studies in the future, for example, utilizing the global repository of FFPE tissues in meningioma and possibly in other cancers.
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Affiliation(s)
- Arijit Mukherjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Susmita Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Deeptarup Biswas
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Aishwarya Rao
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | | | | | | | - Sanjeeva Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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18
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Alternative tissue fixation for combined histopathological and molecular analysis in a clinically representative setting. Histochem Cell Biol 2021; 156:595-607. [PMID: 34905068 PMCID: PMC8695534 DOI: 10.1007/s00418-021-02029-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2021] [Indexed: 11/26/2022]
Abstract
Formalin is the principal tissue fixative used worldwide for clinical and research purposes. Despite optimal preservation of morphology, its preservation of DNA and RNA is poor. As clinical diagnostics increasingly incorporates molecular-based analysis, the requirement for maintaining nucleic acid quality is of increasing importance. Here we assess an alternative non-formalin-based tissue fixation method, PAXgene Tissue system, with the aim of better preserving nucleic acids, while maintaining the quality of the tissue to be used for vital existing diagnostic techniques. In this study, these criteria are assessed in a clinically representative setting. In total, 203 paired PAXgene Tissue and formalin-fixed samples were obtained. Blind-scored haematoxylin and eosin (H&E) sections showed comparable and acceptable staining. Immunohistochemistry (IHC) staining was suboptimal using existing protocols but improved with minor method adjustment and optimisation. Quality of DNA and RNA was significantly improved by PAXgene tissue fixation [RIN 2.8 versus 3.8 (p < 0.01), DIN 5.68 versus 6.77 (p < 0.001)], which translated into improved performance on qPCR assay. These results demonstrate the potential of PAXgene Tissue to be used routinely in place of formalin, maintaining adequate histological staining and significantly improving the preservation of biological molecules in the genomic era.
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19
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Yu Q, Zhang C, Huang W, Li L. Heat-induced antigen retrieval in fluorescence in situ hybridization: An effective approach enhancing signal intensity in poor-quality FFPE sections. Exp Ther Med 2021; 22:1480. [PMID: 34765021 PMCID: PMC8576618 DOI: 10.3892/etm.2021.10915] [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: 07/01/2021] [Accepted: 09/17/2021] [Indexed: 11/06/2022] Open
Abstract
Fluorescence in situ hybridization (FISH) serves as an ancillary tool for assessing chromosomal abnormalities and is important in differential diagnoses and treatment decisions. In clinical practice, pathologists encounter unsatisfactory formalin-fixed paraffin-embedded (FFPE) sections exhibiting weak fluorescence signals, mostly due to inappropriate tissue processing or preservation, leading to interpretation difficulties. For the present study, FFPE samples for which conventional FISH failed were collected. Instead of a pretreatment step using a commercial kit, heat-induced antigen retrieval (HIAR) was introduced using either citrate buffer or Tris-EDTA buffer, while the subsequent experimental workflow remained unchanged. After HIAR-assisted FISH, the hybridization efficiency and signal intensity were markedly enhanced and no difference in signal adequacy was observed when comparing the effect of the two AR solutions. The present study demonstrated that HIAR is a reliable tool for FISH, particularly for poor-quality FFPE sections yielding weak or no fluorescence signals in the conventional analysis.
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Affiliation(s)
- Qiuxiao Yu
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong 518116, P.R. China
| | - Chi Zhang
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong 518116, P.R. China
| | - Wenting Huang
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong 518116, P.R. China
| | - Li Li
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, Guangdong 518116, P.R. China
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20
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Rijs Z, Jeremiasse B, Shifai N, Gelderblom H, Sier CFM, Vahrmeijer AL, van Leeuwen FWB, van der Steeg AFW, van de Sande MAJ. Introducing Fluorescence-Guided Surgery for Pediatric Ewing, Osteo-, and Rhabdomyosarcomas: A Literature Review. Biomedicines 2021; 9:biomedicines9101388. [PMID: 34680505 PMCID: PMC8533294 DOI: 10.3390/biomedicines9101388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 02/07/2023] Open
Abstract
Sarcomas are a rare heterogeneous group of malignant neoplasms of mesenchymal origin which represent approximately 13% of all cancers in pediatric patients. The most prevalent pediatric bone sarcomas are osteosarcoma (OS) and Ewing sarcoma (ES). Rhabdomyosarcoma (RMS) is the most frequently occurring pediatric soft tissue sarcoma. The median age of OS and ES is approximately 17 years, so this disease is also commonly seen in adults while non-pleiomorphic RMS is rare in the adult population. The mainstay of all treatment regimens is multimodal treatment containing chemotherapy, surgical resection, and sometimes (neo)adjuvant radiotherapy. A clear resection margin improves both local control and overall survival and should be the goal during surgery with a curative intent. Real-time intraoperative fluorescence-guided imaging could facilitate complete resections by visualizing tumor tissue during surgery. This review evaluates whether non-targeted and targeted fluorescence-guided surgery (FGS) could be beneficial for pediatric OS, ES, and RMS patients. Necessities for clinical implementation, current literature, and the positive as well as negative aspects of non-targeted FGS using the NIR dye Indocyanine Green (ICG) were evaluated. In addition, we provide an overview of targets that could potentially be used for FGS in OS, ES, and RMS. Then, due to the time- and cost-efficient translational perspective, we elaborate on the use of antibody-based tracers as well as their disadvantages and alternatives. Finally, we conclude with recommendations for the experiments needed before FGS can be implemented for pediatric OS, ES, and RMS patients.
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Affiliation(s)
- Zeger Rijs
- Department of Orthopedic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (N.S.); (M.A.J.v.d.S.)
- Correspondence: ; Tel.: +31-641-637-074
| | - Bernadette Jeremiasse
- Department of Surgery, Princess Maxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands; (B.J.); (A.F.W.v.d.S.)
| | - Naweed Shifai
- Department of Orthopedic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (N.S.); (M.A.J.v.d.S.)
| | - Hans Gelderblom
- Department of Medical Oncology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands;
| | - Cornelis F. M. Sier
- Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (C.F.M.S.); (A.L.V.)
- Percuros BV, 2333 CL Leiden, The Netherlands
| | - Alexander L. Vahrmeijer
- Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (C.F.M.S.); (A.L.V.)
| | - Fijs W. B. van Leeuwen
- Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands;
| | - Alida F. W. van der Steeg
- Department of Surgery, Princess Maxima Center for Pediatric Oncology, Heidelberglaan 25, 3584 CS Utrecht, The Netherlands; (B.J.); (A.F.W.v.d.S.)
| | - Michiel A. J. van de Sande
- Department of Orthopedic Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; (N.S.); (M.A.J.v.d.S.)
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21
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Yang D, Li S, Wu J. A Simple and Quick Method for Decalcification Using Mouse Tail as a Model for Preparation of Lymphedema Study. Appl Immunohistochem Mol Morphol 2021; 29:551-556. [PMID: 33710121 DOI: 10.1097/pai.0000000000000927] [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: 07/13/2020] [Accepted: 01/27/2021] [Indexed: 11/26/2022]
Abstract
The disadvantage of 10% EDTA decalcification is a long time-consuming. It needs to identify a quick and straightforward decalcification method when the preparation of lymphedema models using mouse tail which was a sample of bone wrapped in other tissues. In the present study, mouse tail samples were decalcified in 10% EDTA at 25, 37, and 42°C, respectively, with continuous shaking (150 rpm/min). The histologic integrity of samples was evaluated by hematoxylin and eosin staining, and the preservation of antigenicity was tested by either immunohistochemistry or immunofluorescence. The decalcification was distinctly accelerated by temperature. Results of hematoxylin and eosin staining were similar among different temperature groups. Immunohistochemistry and immunofluorescence staining revealed almost no signals in samples decalcified at 42°C for 1 week. Clear signals were detected when samples were decalcified at 37 and 25°C.
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Affiliation(s)
- Duo Yang
- Beijing Key Laboratory for Therapeutic Cancer Vaccines, Beijing Shijitan Hospital, Capital Medical University, Beijing, China
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22
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Sinsky J, Majerova P, Kovac A, Kotlyar M, Jurisica I, Hanes J. Physiological Tau Interactome in Brain and Its Link to Tauopathies. J Proteome Res 2020; 19:2429-2442. [PMID: 32357304 DOI: 10.1021/acs.jproteome.0c00137] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Alzheimer's disease (AD) and most of the other tauopathies are incurable neurodegenerative diseases with unpleasant symptoms and consequences. The common hallmark of all of these diseases is tau pathology, but its connection with disease progress has not been completely understood so far. Therefore, uncovering novel tau-interacting partners and pathology affected molecular pathways can reveal the causes of diseases as well as potential targets for the development of AD treatment. Despite the large number of known tau-interacting partners, a limited number of studies focused on in vivo tau interactions in disease or healthy conditions are available. Here, we applied an in vivo cross-linking approach, capable of capturing weak and transient protein-protein interactions, to a unique transgenic rat model of progressive tau pathology similar to human AD. We have identified 175 potential novel and known tau-interacting proteins by MALDI-TOF mass spectrometry. Several of the most promising candidates for possible drug development were selected for validation by coimmunoprecipitation and colocalization experiments in animal and cellular models. Three proteins, Baiap2, Gpr37l1, and Nptx1, were confirmed as novel tau-interacting partners, and on the basis of their known functions and implications in neurodegenerative or psychiatric disorders, we proposed their potential role in tau pathology.
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Affiliation(s)
- Jakub Sinsky
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84510, Slovakia
| | - Petra Majerova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84510, Slovakia.,AXON Neuroscience R&D Services SE, Dvorakovo nabrezie 10, Bratislava 811 02, Slovakia
| | - Andrej Kovac
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84510, Slovakia.,AXON Neuroscience R&D Services SE, Dvorakovo nabrezie 10, Bratislava 811 02, Slovakia
| | - Max Kotlyar
- Krembil Research Institute, UHN, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada
| | - Igor Jurisica
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84510, Slovakia.,Krembil Research Institute, UHN, 60 Leonard Avenue, Toronto, Ontario M5T 0S8, Canada.,Departments of Medical Biophysics and Computer Science, University of Toronto, 27 King's College Circle, Toronto, Ontario ON M5S, Canada
| | - Jozef Hanes
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava 84510, Slovakia.,AXON Neuroscience R&D Services SE, Dvorakovo nabrezie 10, Bratislava 811 02, Slovakia
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Cummings M, King H, Hurst J, Tanner G, Khazin L, Thompson P, Gray A, Gahir N, Cartlidge C, Farooq Z, Raveendran K, Allen K, Rotimi O, Orsi NM. Decreasing formalin concentration improves quality of DNA extracted from formalin-fixed paraffin-embedded tissue specimens without compromising tissue morphology or immunohistochemical staining. J Clin Pathol 2020; 73:514-518. [PMID: 31919142 DOI: 10.1136/jclinpath-2019-206368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 11/03/2022]
Abstract
Genomic technologies are increasingly used clinically for both diagnosis and guiding cancer therapy. However, formalin fixation can compromise DNA quality. This study aimed to optimise tissue fixation using normal colon, liver and uterus (n=8 each) by varying neutral buffered formalin (NBF) concentration (1%-5% w/v) and fixation time (24-48 hours). Fixation using 4% NBF improved DNA quality (assessed by qPCR) compared with routine (4% unbuffered formal saline-fixed) specimens (p<0.01). Further improvements were achieved by reducing NBF concentration (p<0.00001), whereas fixation time had no effect (p=0.110). No adverse effects were detected by histopathological or QuPath morphometric analysis. Immunohistochemistry for multicytokeratin and α-smooth muscle actin revealed no changes in staining specificity or intensity in any tissue other than on liver multicytokeratin staining intensity, where the effect of fixation time was more significant (p=0.0004) than NBF concentration (p=0.048). Thus, reducing NBF concentration can maximise DNA quality without compromising tissue morphology or standard histopathological analyses.
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Affiliation(s)
- Michele Cummings
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Henry King
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - James Hurst
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Georgette Tanner
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Leah Khazin
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Phillip Thompson
- Department of Histopathology, St. James's University Hospital, Leeds, UK
| | - Allan Gray
- Department of Histopathology, St. James's University Hospital, Leeds, UK
| | - Narinder Gahir
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Caroline Cartlidge
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Zara Farooq
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Keyura Raveendran
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
| | - Katie Allen
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK.,Department of Histopathology, St. James's University Hospital, Leeds, UK
| | - Olorunda Rotimi
- Department of Histopathology, St. James's University Hospital, Leeds, UK
| | - Nicolas M Orsi
- Women's Health Research Group, Pathology & Data Analytics, Leeds Institute of Medical Research at St. James's, University of Leeds, Wellcome Trust Brenner Building, Leeds, UK
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24
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Dodson A, Parry S, Lissenberg-Witte B, Haragan A, Allen D, O'Grady A, McClean E, Hughes J, Miller K, Thunnissen E. External quality assessment demonstrates that PD-L1 22C3 and SP263 assays are systematically different. JOURNAL OF PATHOLOGY CLINICAL RESEARCH 2019; 6:138-145. [PMID: 31849189 PMCID: PMC7164369 DOI: 10.1002/cjp2.153] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/18/2019] [Accepted: 11/24/2019] [Indexed: 12/20/2022]
Abstract
PD‐L1 inhibitors are part of first line treatment options for patients with advanced non‐small cell lung cancer. PD‐L1 immunohistochemistry (IHC) assays act as either a companion or a complementary diagnostic. The purpose of this study is to describe the experience of external quality assurance (EQA) provider UK NEQAS ICC and ISH with the comparison of different PD‐L1 assays used in daily practice. Three EQA rounds (pilot, run A and run B) were carried out using formalin fixed paraffin embedded samples with sample sets covering a range of epitope concentrations, including ‘critical samples’ near to clinical threshold cut‐offs. An expert panel (n = 4) evaluated all returned slides simultaneously and independently on a multi‐header microscope together with the participants own in‐house control material. The tonsil sample was evaluated as ‘acceptable’ or ‘unacceptable’, and for the other samples the percentage of PD‐L1 stained tumour cells were estimated in predetermined categories (<1%, 1 to <5%, 5 to <10%, 10 to <25%, 25 to <50%, 50 to <80%, 80 to 100%). In the pilot and the two subsequent runs the number of participating laboratories was 43, 69 and 76, respectively. The pass rate for the pilot run was 67%; this increased to 81% at run A and 82% at run B. For two ‘critical samples’, in runs A and B, 22C3 IHC had significantly higher PD‐L1 expression than SP263 IHC (p < 0.001), whilst the PD‐L1 scores for the other six samples were similar for all assays. In run A the laboratory developed tests (LDTs) using 22C3 scored lower than the commercial 22C3 tests (p = 0.01). After the initial testing, improvement in performance of PD‐L1 IHC is shown for approved and LDT PD‐L1 assays. Equivalency of approved PD‐L1 22C3 and SP263 assays cannot be assumed as the scores cross the clinically relevant thresholds of 1% and 50% PD‐L1 expression.
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Affiliation(s)
- Andrew Dodson
- UK National External Quality Assessment Scheme for Immunocytochemistry and In-Situ Hybridisation, London, UK
| | - Suzanne Parry
- UK National External Quality Assessment Scheme for Immunocytochemistry and In-Situ Hybridisation, London, UK
| | - Birgit Lissenberg-Witte
- Department of Epidemiology and Biostatistics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Alex Haragan
- Department of Pathology, Royal Liverpool and Broadgreen University Hospitals, Liverpool, UK
| | | | - Anthony O'Grady
- Department of Pathology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Emma McClean
- Oncology, Haematology and Cellular Pathology, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Jamie Hughes
- UK National External Quality Assessment Scheme for Immunocytochemistry and In-Situ Hybridisation, London, UK
| | - Keith Miller
- UK National External Quality Assessment Scheme for Immunocytochemistry and In-Situ Hybridisation, London, UK
| | - Erik Thunnissen
- Department of Pathology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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25
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Southwood M, Krenz T, Cant N, Maurya M, Gazdova J, Maxwell P, McGready C, Moseley E, Hughes S, Stewart P, Salto-Tellez M, Groelz D, Rassl D. Systematic evaluation of PAXgene® tissue fixation for the histopathological and molecular study of lung cancer. JOURNAL OF PATHOLOGY CLINICAL RESEARCH 2019; 6:40-54. [PMID: 31571426 PMCID: PMC6966705 DOI: 10.1002/cjp2.145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/04/2019] [Accepted: 09/13/2019] [Indexed: 12/25/2022]
Abstract
Whilst adequate for most existing pathological tests, formalin is generally considered a poor DNA preservative and use of alternative fixatives may prove advantageous for molecular testing of tumour material; an increasingly common approach to identify targetable driver mutations in lung cancer patients. We collected paired PAXgene® tissue-fixed and formalin-fixed samples of block-sized tumour and lung parenchyma, Temno-needle core tumour biopsies and fine needle tumour aspirates (FNAs) from non-small cell lung cancer resection specimens. Traditionally processed formalin fixed paraffin wax embedded (FFPE) samples were compared to paired PAXgene® tissue fixed paraffin-embedded (PFPE) samples. We evaluated suitability for common laboratory tests (H&E staining and immunohistochemistry) and performance for downstream molecular investigations relevant to lung cancer, including RT-PCR and next generation DNA sequencing (NGS). Adequate and comparable H&E staining was seen in all sample types and nuclear staining was preferable in PAXgene® fixed Temno tumour biopsies and tumour FNA samples. Immunohistochemical staining was broadly comparable. PFPE samples enabled greater yields of less-fragmented DNA than FFPE comparators. PFPE samples were also superior for PCR and NGS performance, both in terms of quality control metrics and for variant calling. Critically we identified a greater number of genetic variants in the epidermal growth factor receptor gene when using PFPE samples and the Ingenuity® Variant Analysis pipeline. In summary, PFPE samples are adequate for histopathological diagnosis and suitable for the majority of existing laboratory tests. PAXgene® fixation is superior for DNA and RNA integrity, particularly in low-yield samples and facilitates improved NGS performance, including the detection of actionable lung cancer mutations for precision medicine in lung cancer samples.
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Affiliation(s)
- Mark Southwood
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, University of Cambridge Clinical School of Medicine, Cambridge, UK
| | - Tomasz Krenz
- Sample Technologies Department, QIAGEN GmbH, Hilden, Germany
| | - Natasha Cant
- Sample Technologies Department, QIAGEN Ltd., Manchester, UK
| | - Manisha Maurya
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Jana Gazdova
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Perry Maxwell
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Claire McGready
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Ellen Moseley
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, University of Cambridge Clinical School of Medicine, Cambridge, UK
| | - Susan Hughes
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Peter Stewart
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Manuel Salto-Tellez
- Northern Ireland Molecular Pathology Laboratory, Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Daniel Groelz
- Sample Technologies Department, QIAGEN GmbH, Hilden, Germany
| | - Doris Rassl
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, University of Cambridge Clinical School of Medicine, Cambridge, UK
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