Journal Article

DKFZ-2019-02539

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Molecular characterization of histopathological ependymoma variants.

Neumann, J. E. ; Spohn, M. ; Obrecht, D. ; Mynarek, M. ; Thomas, C. ; Hasselblatt, M. ; Dorostkar, M. M. ; Wefers, A. K.DKFZ* ; Frank, S. ; Monoranu, C.-M. ; Koch, A. ; Witt, H.DKFZ* ; Kool, M.DKFZ* ; Pajtler, K. W.DKFZ* ; Rutkowski, S. ; Glatzel, M. ; Schüller, U.

2020
Springer Heidelberg

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Please use a persistent id in citations: doi:10.1007/s00401-019-02090-0

Abstract: According to the WHO classification, ependymal tumors are classified as subependymomas, myxopapillary ependymomas, classic ependymomas, anaplastic ependymomas, and RELA-fusion-positive ependymomas (RELA-EPN). Among classic ependymomas, the WHO defines rare histological variants, i.e., the clear cell, papillary, and tanycytic ependymoma. In parallel, global DNA methylation patterns distinguish nine molecular groups, some of which tightly overlap with histopathological subgroups. However, the match of the aforementioned histological variants to DNA methylation classes remains unclear. We analyzed histomorphology, clinical parameters, and global DNA methylation of tumors with the initial histological diagnoses of tanycytic (n = 12), clear cell (n = 14), or papillary ependymoma (n = 19). Forty percent of these tumors did not match to the epigenetic profile of ependymomas, using a previously published DNA methylation-based classifier for brain tumors. Instead, they were classified as low-grade glioma (n = 3), plexus tumor (n = 2), CNS high-grade neuroepithelial tumor with MN1 alteration (n = 2), papillary tumor of the pineal region (n = 2), neurocytoma (n = 1), or did not match to any known brain tumor methylation class (n = 8). Overall, integrated diagnosis had to be changed in 35.6% of cases as compared to the initial diagnosis. Among the tumors molecularly classified as ependymoma (27/45 cases), tanycytic ependymomas were mostly located in the spine (5/7 cases) and matched to spinal or myxopapillary ependymoma. 6/8 clear cell ependymomas were found supratentorially and fell into the methylation class of RELA-EPN. Papillary ependymomas with a positive ependymoma match (12/19 cases) showed either a 'papillary' (n = 5), a 'trabecular' (n = 1), or a 'pseudo-papillary' (n = 6) growth pattern. The papillary growth pattern was strongly associated with the methylation class B of posterior fossa ependymoma (PFB, 5/5 cases) and tumors displayed DNA methylation sites that were significantly different when compared to PFB ependymomas without papillary growth. Tumors with pseudo-papillary histology matched to the methylation class of myxopapillary ependymoma (4/6 cases), whereas the trabecular case was anatomically and molecularly a spinal ependymoma. Our results show that the diagnosis of histological ependymoma variants is challenging and epigenetic profiles may improve diagnostic accuracy of these cases. Whereas clear cell and papillary ependymomas display correlations between localization, histology, and methylation, tanycytic ependymoma does not represent a molecularly distinct subgroup.

Note: 2020 Feb;139(2):305-318

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Contributing Institute(s):

1. KKE Neuropathologie (B300)
2. Pädiatrische Neuroonkologie (B062)
3. DKTK HD zentral (HD01)

Research Program(s):

1. 312 - Functional and structural genomics (POF3-312) (POF3-312)

Appears in the scientific report 2020

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Database coverage:
; BIOSIS Previews ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Ebsco Academic Search ; IF >= 15 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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