Skip to main content

Molecular reclassification reveals low prevalence of germline predisposition in children with ependymoma

Main text

Ependymoma is the second most common malignant childhood brain tumor, accounting for approximately 6% of all central nervous system (CNS) tumors in children [6]. Nonetheless, our knowledge of its underlying etiology is sparse. Since the introduction of next-generation sequencing, several pan-childhood cancer germline sequencing studies have been published covering more than 1,400 children with CNS tumors, including 191 ependymomas (as recently reviewed [4]). In combination, these studies report 4.7% (9/191) of children with ependymoma to harbor pathogenic germline variants likely underlying the cancer pathogenesis, although individual study estimates range from 0 to more than 20%. Moreover, differing approaches to variant classification and the lack of molecular tumor diagnostics and population-based study designs challenge drawing inferences about the true nature of genetic predisposition for these children. In 2022, we, therefore, reported the findings from our nationwide, population-based germline whole-genome sequencing study specific to children with molecularly classified ependymoma diagnosed in Denmark years 2000–2021 in Acta Neuropathologica Communications [4].

More recently, Sturm et al. published an international population-based prospective study of 1,204 children with CNS tumors undergoing tumor methylation profiling, targeted tumor sequencing as well as targeted germline sequencing of 47 known cancer predisposition genes [9]. This cohort included 127 children with histopathologically diagnosed ependymoma. Similarly to the 7.7% reclassification rate in our report [4], tumor methylation profiling indicated amendment to a non-ependymoma tumor type in 7.1% in Sturm et al.’s cohort. This included a histopathologically diagnosed ependymoma WHO grade 3 of the third ventricle, which was revised to an embryonal tumor with multilayered rosettes (ETMR), just as in our cohort. Furthermore, six children with other tumor types were reclassified as having ependymomas following tumor methylation profiling. Of the 116 children with histopathologically diagnosed ependymoma who underwent targeted germline sequencing in the study by Sturm et al., 5.2% (n = 6) were found to harbor pathogenic germline variants considered to be causative of disease (NF2 in three patients, BRCA1, PTEN and PTCH1). However, following molecular tumor classification using the predicted methylation class with the highest calibrated score from version 12.5 of the Heidelberg classifier [2], the prevalence declined to 2.7% (3/112; NF2 in two patients and BRCA1)(Fig. 1.). Our findings were very similar with 10.8% and 5.9% harboring pathogenic germline variants, respectively, of which the latter were limited to NF2 and LTZR1.

In other words, 50% of children with histopathologically diagnosed ependymoma and identified pathogenic germline variants were reclassified to having a non-ependymoma tumor type following methylation profiling in both studies (3/6 and 2/4, respectively, Fig. 1). Thus, diagnostic reclassification from histopathological ependymoma to a molecularly classified non-ependymoma tumor type was significantly more likely in children harboring pathogenic germline variants in both Sturm et al.’s and our cohort (5/10 vs. 6/139, p-value < 0.001, Fisher’s exact test, combined data). The background for this higher rate of misclassification remains unknown and merits further investigation.

Fig. 1
figure 1

Overview of diagnostic reclassification of original histopathological ependymoma diagnoses following tumor methylation profiling. In Sturm et al.’s study, six additional children were reclassified from other non-ependymoma tumor types to ependymoma following tumor methylation profiling (not shown). Targeted germline sequencing was performed for five without detection of pathogenic variants. Adapted from Foss-Skiftesvik et al. Acta Neuropathologica Communications(2022) 10:123, https://doi.org/10.1186/s40478-022-01429-1 with permission under the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/). Created with BioRender.com

Our previous best prevalence estimate for predisposing germline variants in children with ependymoma was 3.4%. This was based on pooling our recently reported cohort with a comprehensive quantitative review of the existing literature [4], which, of note, is predominated by non-population-based studies of children with non-molecularly classified intracranial ependymoma. From the current reanalysis, it is evident that predisposing pathogenic germline variants are significantly less common in children with molecularly classified ependymoma compared to other childhood CNS tumors overall (5/146 vs. 98/922 (non-ependymoma childhood CNS tumors included in Sturm et al.’s study), p-value 0.004, Fisher’s exact test).

Interestingly, in children with ependymoma, all previously reported pathogenic germline TP53 and NF1 variants have either subsequently been reclassified as benign, or described in children for whom tumor methylation profiling has not been reported [1, 3, 5, 7, 8, 10, 11]. This calls into question the link between both Li-Fraumeni Syndrome and neurofibromatosis type-1 and (molecularly classified) ependymoma. Although the BRCA1 variant reported by Sturm et al. has been interpreted by several sources as likely pathogenic (ClinVar accession number VCV000037565.30), its role in childhood ependymoma may also be questioned as the variant more recently has received class 3 classification (variant of unknown significance) following expert panel evaluation by the Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA). Unfortunately, somatic loss-of-heterozygosity status for the pathogenic LTZR1 variant from our cohort was not available, and its causal relationship with ependymoma may also be considered speculative. If excluded (the BRCA1 and LZTR1 variants), the prevalence of rare pathogenic germline variants in children with molecularly classified ependymoma decreases further to less than 3% (2.1%, 3/146), with mutations observed exclusively in NF2 in children with methylation class spinal ependymoma.

These data emphasize the need for both germline and tumor DNA profiling in children with CNS tumors and highlight the exceptional scarcity of germline mutations in children with molecularly classified intracranial ependymoma. Identification of cancer predisposition syndromes other than neurofibromatosis type-2 should warrant diagnostic reconsideration in children with ependymoma for whom molecular classification has not been performed. We encourage future studies of germline predisposition in children with ependymoma to include tumor molecular classification. As we have previously shown, this is feasible also for retrospective studies using archived tumor samples stored for more than 20 years [4].

Data Availability

Not applicable.

Abbreviations

CNS:

Central nervous system

WHO:

World Health Organization

ETMR:

Embryonal tumor with multilayered rosettes

ENIGMA:

The Evidence-based Network for the Interpretation of Germline Mutant Alleles

References

  1. Bougeard G, Renaux-Petel M, Flaman J-M, Charbonnier C, Fermey P, Belotti M, Gauthier-Villars M, Stoppa-Lyonnet D, Consolino E, Brugières L, Caron O, Benusiglio PR, Bressac-de Paillerets B, Bonadona V, Bonaïti-Pellié C, Tinat J, Baert-Desurmont S, Frebourg T (2015) Revisiting Li-Fraumeni Syndrome from TP53 mutation carriers. J Clin Oncol 33:2345–2352. https://doi.org/10.1200/JCO.2014.59.5728

    Article  CAS  PubMed  Google Scholar 

  2. Capper D, Jones DTW, Sill M, Hovestadt V, Schrimpf D, Sturm D, Koelsche C, Sahm F, Chavez L, Reuss DE, Kratz A, Wefers AK, Huang K, Pajtler KW, Schweizer L, Stichel D, Olar A, Engel NW, Lindenberg K, Harter PN, Braczynski AK, Plate KH, Dohmen H, Garvalov BK, Coras R, Hölsken A, Hewer E, Bewerunge-Hudler M, Schick M, Fischer R, Beschorner R, Schittenhelm J, Staszewski O, Wani K, Varlet P, Pages M, Temming P, Lohmann D, Selt F, Witt H, Milde T, Witt O, Aronica E, Giangaspero F, Rushing E, Scheurlen W, Geisenberger C, Rodriguez FJ, Becker A, Preusser M, Haberler C, Bjerkvig R, Cryan J, Farrell M, Deckert M, Hench J, Frank S, Serrano J, Kannan K, Tsirigos A, Brück W, Hofer S, Brehmer S, Seiz-Rosenhagen M, Hänggi D, Hans V, Rozsnoki S, Hansford JR, Kohlhof P, Kristensen BW, Lechner M, Lopes B, Mawrin C, Ketter R, Kulozik A, Khatib Z, Heppner F, Koch A, Jouvet A, Keohane C, Mühleisen H, Mueller W, Pohl U, Prinz M, Benner A, Zapatka M, Gottardo NG, Driever PH, Kramm CM, Müller HL, Rutkowski S, Von Hoff K, Frühwald MC, Gnekow A, Fleischhack G, Tippelt S, Calaminus G, Monoranu CM, Perry A, Jones C, Jacques TS, Radlwimmer B, Gessi M, Pietsch T, Schramm J, Schackert G, Westphal M, Reifenberger G, Wesseling P, Weller M, Collins VP, Blümcke I, Bendszus M, Debus J, Huang A, Jabado N, Northcott PA, Paulus W, Gajjar A, Robinson GW, Taylor MD, Jaunmuktane Z, Ryzhova M, Platten M, Unterberg A, Wick W, Karajannis MA, Mittelbronn M, Acker T, Hartmann C, Aldape K, Schüller U, Buslei R, Lichter P, Kool M, Herold-Mende C, Ellison DW, Hasselblatt M, Snuderl M, Brandner S, Korshunov A, Von Deimling A, Pfister SM (2018) DNA methylation-based classification of central nervous system tumours. Nature. doi: https://doi.org/10.1038/nature26000

  3. Fiala EM, Jayakumaran G, Mauguen A, Kennedy JA, Bouvier N, Kemel Y, Fleischut MH, Maio A, Salo-Mullen EE, Sheehan M, Arnold AG, Latham A, Carlo MI, Cadoo K, Murkherjee S, Slotkin EK, Trippett T, Glade Bender J, Meyers PA, Wexler L, Dela Cruz FS, Cheung N-K, Basu E, Kentsis A, Ortiz M, Francis JH, Dunkel IJ, Khakoo Y, Gilheeney S, Farouk Sait S, Forlenza CJ, Sulis M, Karajannis M, Modak S, Gerstle JT, Heaton TE, Roberts S, Yang C, Jairam S, Vijai J, Topka S, Friedman DN, Stadler ZK, Robson M, Berger MF, Schultz N, Ladanyi M, O’Reilly RJ, Abramson DH, Ceyhan-Birsoy O, Zhang L, Mandelker D, Shukla NN, Kung AL, Offit K, Zehir A, Walsh MF (2021) Prospective pan-cancer germline testing using MSK-IMPACT informs clinical translation in 751 patients with pediatric solid tumors. Nat Cancer 2:357–365. https://doi.org/10.1038/s43018-021-00172-1

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Foss-Skiftesvik J, Stoltze UK, van Overeem Hansen T, Ahlborn LB, Sørensen E, Ostrowski SR, Kullegaard SMA, Laspiur AO, Melchior LC, Scheie D, Kristensen BW, Skjøth-Rasmussen J, Schmiegelow K, Wadt K, Mathiasen R (2022) Redefining germline predisposition in children with molecularly characterized ependymoma: a population-based 20-year cohort. Acta Neuropathol Commun 10:123. https://doi.org/10.1186/s40478-022-01429-1

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Gröbner SN, Worst BC, Weischenfeldt J, Buchhalter I, Kleinheinz K, Rudneva VA, Johann PD, Balasubramanian GP, Segura-Wang M, Brabetz S, Bender S, Hutter B, Sturm D, Pfaff E, Hübschmann D, Zipprich G, Heinold M, Eils J, Lawerenz C, Erkek S, Lambo S, Waszak S, Blattmann C, Borkhardt A, Kuhlen M, Eggert A, Fulda S, Gessler M, Wegert J, Kappler R, Baumhoer D, Burdach S, Kirschner-Schwabe R, Kontny U, Kulozik AE, Lohmann D, Hettmer S, Eckert C, Bielack S, Nathrath M, Niemeyer C, Richter GH, Schulte J, Siebert R, Westermann F, Molenaar JJ, Vassal G, Witt H, Zapatka M, Burkhardt B, Kratz CP, Witt O, Tilburg CMV, Kramm CM, Fleischhack G, Dirksen U, Rutkowski S, Frühwald M, Hoff VK, Wolf S, Klingebiel T, Koscielniak E, Landgraf P, Koster J, Resnick AC, Zhang J, Liu Y, Zhou X, Waanders AJ, Zwijnenburg DA, Raman P, Brors B, Weber UD, Northcott PA, Pajtler KW, Kool M, Piro RM, Korbel JO, Schlesner M, Eils R, Jones DTW, Lichter P, Chavez L, Pfister SM (2018) The landscape of genomic alterations across childhood cancers. Nature 555:321–327. https://doi.org/10.1038/nature25480

    Article  CAS  PubMed  Google Scholar 

  6. Helligsoe ASL, Kenborg L, Henriksen LT, Udupi A, Hasle H, Winther JF (2022) Incidence and survival of childhood central nervous system tumors in Denmark, 1997–2019. Cancer Med 11:245–256. https://doi.org/10.1002/cam4.4429

    Article  PubMed  Google Scholar 

  7. Hosoya T, Kambe A, Nishimura Y, Sakamoto M, Maegaki Y, Kurosaki M (2018) Pediatric Case of Li-Fraumeni Syndrome Complicated with Supratentorial Anaplastic Ependymoma. World Neurosurg 120:125–128. https://doi.org/10.1016/j.wneu.2018.08.203

    Article  PubMed  Google Scholar 

  8. Metzger AK, Sheffield VC, Duyk G, Daneshvar L, Edwards MS, Cogen PH (1991) Identification of a germ-line mutation in the p53 gene in a patient with an intracranial ependymoma. Proc Natl Acad Sci U S A 88:7825–7829. https://doi.org/10.1073/pnas.88.17.7825

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Sturm D, Capper D, Andreiuolo F, Gessi M, Kölsche C, Reinhardt A, Sievers P, Wefers AK, Ebrahimi A, Suwala AK, Gielen GH, Sill M, Schrimpf D, Stichel D, Hovestadt V, Daenekas B, Rode A, Hamelmann S, Previti C, Jäger N, Buchhalter I, Blattner-Johnson M, Jones BC, Warmuth-Metz M, Bison B, Grund K, Sutter C, Hirsch S, Dikow N, Hasselblatt M, Schüller U, Gerber NU, White CL, Buntine MK, Kinross K, Algar EM, Hansford JR, Gottardo NG, Hernáiz Driever P, Gnekow A, Witt O, Müller HL, Calaminus G, Fleischhack G, Kordes U, Mynarek M, Rutkowski S, Frühwald MC, Kramm CM, von Deimling A, Pietsch T, Sahm F, Pfister SM, Jones DTW (2023) Multiomic neuropathology improves diagnostic accuracy in pediatric neuro-oncology. Nat Med 1–10. doi: https://doi.org/10.1038/s41591-023-02255-1

  10. Van Es S, North KN, McHugh K, De Silva M (1996) MRI findings in children with neurofibromatosis type 1: a prospective study. Pediatr Radiol 26:478–487. https://doi.org/10.1007/BF01377205

    Article  PubMed  Google Scholar 

  11. Zhang J, Walsh MF, Wu G, Edmonson MN, Gruber TA, Easton J, Hedges D, Ma X, Zhou X, Yergeau DA, Wilkinson MR, Vadodaria B, Chen X, McGee RB, Dowell SH, Nuccio R, Quinn E, Shurtleff SA, Rusch M, Patel A, Becksfort JB, Wang S, Weaver MS, Ding L, Mardis ER, Wilson RK, Gajjar A, Ellison DW, Pappo AS, Pui CH, Nichols KE, Downing JR (2015) Germline mutations in predisposition genes in pediatric cancer. N Engl J Med 373:2336–2346. https://doi.org/10.1056/NEJMoa1508054

    Article  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Funding

The authors are supported by the Danish Cancer Society (R-257-A14720, the Childhood Oncology Network Targeting Research, Organization & Life expectancy (CONTROL)), the Danish Childhood Cancer Foundation (2019–5934), and the Danish Childhood Brain Tumor Foundation.

Author information

Authors and Affiliations

Authors

Contributions

Conception: JFS, UKS. Acquisition and analysis: JFS, UKS, TvOH. Interpretation of data: All authors. JFS and UKS drafted the letter. All authors contributed to its revision and reviewed and approved of the final version.

Corresponding author

Correspondence to Jon Foss-Skiftesvik.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

None to declare.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Foss-Skiftesvik, J., Mathiasen, R., van Overeem Hansen, T. et al. Molecular reclassification reveals low prevalence of germline predisposition in children with ependymoma. acta neuropathol commun 11, 94 (2023). https://doi.org/10.1186/s40478-023-01594-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s40478-023-01594-x

Keywords