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Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma
BACKGROUND: Metaplastic thymoma (MT) is a very uncommon thymoma type, with biphasic differentiation as one of its histological characteristics. This histological pattern, however, can also be mistaken for type A thymoma and the A component in type AB thymoma. METHODS: Postoperative specimens were co...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Taylor & Francis
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10392284/ https://www.ncbi.nlm.nih.gov/pubmed/37489594 http://dx.doi.org/10.1080/07853890.2023.2237040 |
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author | Wang, Minghao Xu, Hongtao Han, Qiang Wang, Liang |
author_facet | Wang, Minghao Xu, Hongtao Han, Qiang Wang, Liang |
author_sort | Wang, Minghao |
collection | PubMed |
description | BACKGROUND: Metaplastic thymoma (MT) is a very uncommon thymoma type, with biphasic differentiation as one of its histological characteristics. This histological pattern, however, can also be mistaken for type A thymoma and the A component in type AB thymoma. METHODS: Postoperative specimens were collected from five MT and four type A thymomas with a retrospective analysis involving immunohistochemistry, fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS). RESULTS: The histological morphology of the MT overlapped with that of the type A thymoma. With immunostains, the former’s spindle cell components expressed vimentin and EMA, but not CD20. In MT, 3/5 cases had the nuclear expression of YAP1. The spindle cell component of the type A thymoma was found to express CD20. In all five cases of MT, FISH detection revealed YAP1–MAML2 fusion, which was not found in any type A thymoma cases. NGS sequencing confirmed YAP1–MAML2 rearrangement in all five cases of MT, and mutations in POLE and HRAS were also found in two cases, respectively. GTF2I c.74146970 T > A mutations were found in all cases of type A thymoma, and HRAS and NRAS mutations were found in two cases, but no YAP1–MAML2 rearrangement was evident. CONCLUSIONS: For the diagnosis and differential diagnosis of challenging cases, the YAP1–MAML2 rearrangement and GTF2I mutation were both significant molecular events specific to MT and type A thymoma, respectively. |
format | Online Article Text |
id | pubmed-10392284 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | Taylor & Francis |
record_format | MEDLINE/PubMed |
spelling | pubmed-103922842023-08-02 Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma Wang, Minghao Xu, Hongtao Han, Qiang Wang, Liang Ann Med Clinical Pathology BACKGROUND: Metaplastic thymoma (MT) is a very uncommon thymoma type, with biphasic differentiation as one of its histological characteristics. This histological pattern, however, can also be mistaken for type A thymoma and the A component in type AB thymoma. METHODS: Postoperative specimens were collected from five MT and four type A thymomas with a retrospective analysis involving immunohistochemistry, fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS). RESULTS: The histological morphology of the MT overlapped with that of the type A thymoma. With immunostains, the former’s spindle cell components expressed vimentin and EMA, but not CD20. In MT, 3/5 cases had the nuclear expression of YAP1. The spindle cell component of the type A thymoma was found to express CD20. In all five cases of MT, FISH detection revealed YAP1–MAML2 fusion, which was not found in any type A thymoma cases. NGS sequencing confirmed YAP1–MAML2 rearrangement in all five cases of MT, and mutations in POLE and HRAS were also found in two cases, respectively. GTF2I c.74146970 T > A mutations were found in all cases of type A thymoma, and HRAS and NRAS mutations were found in two cases, but no YAP1–MAML2 rearrangement was evident. CONCLUSIONS: For the diagnosis and differential diagnosis of challenging cases, the YAP1–MAML2 rearrangement and GTF2I mutation were both significant molecular events specific to MT and type A thymoma, respectively. Taylor & Francis 2023-07-25 /pmc/articles/PMC10392284/ /pubmed/37489594 http://dx.doi.org/10.1080/07853890.2023.2237040 Text en © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group https://creativecommons.org/licenses/by-nc/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) ), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent. |
spellingShingle | Clinical Pathology Wang, Minghao Xu, Hongtao Han, Qiang Wang, Liang Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title | Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title_full | Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title_fullStr | Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title_full_unstemmed | Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title_short | Significance of YAP1–MAML2 rearrangement and GTF2I mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
title_sort | significance of yap1–maml2 rearrangement and gtf2i mutation in the diagnosis and differential diagnosis of metaplastic thymoma |
topic | Clinical Pathology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10392284/ https://www.ncbi.nlm.nih.gov/pubmed/37489594 http://dx.doi.org/10.1080/07853890.2023.2237040 |
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