%0 Journal Article %A Panwalkar, Pooja %A Clark, Jonathan %A Ramaswamy, Vijay %A Hawes, Debra %A Yang, Fusheng %A Dunham, Christopher %A Yip, Stephen %A Hukin, Juliette %A Sun, Yilun %A Schipper, Matthew J %A Chavez, Lukas %A Margol, Ashley %A Pekmezci, Melike %A Chung, Chan %A Banda, Adam %A Bayliss, Jill M %A Curry, Sarah J %A Santi, Mariarita %A Rodriguez, Fausto J %A Snuderl, Matija %A Karajannis, Matthias A %A Saratsis, Amanda M %A Horbinski, Craig M %A Carret, Anne-Sophie %A Wilson, Beverly %A Johnston, Donna %A Lafay-Cousin, Lucie %A Zelcer, Shayna %A Eisenstat, David %A Silva, Marianna %A Scheinemann, Katrin %A Jabado, Nada %A McNeely, P Daniel %A Kool, Marcel %A Pfister, Stefan %A Taylor, Michael D %A Hawkins, Cynthia %A Korshunov, Andrey %A Judkins, Alexander R %A Venneti, Sriram %T Immunohistochemical analysis of H3K27me3 demonstrates global reduction in group-A childhood posterior fossa ependymoma and is a powerful predictor of outcome. %J Acta neuropathologica %V 134 %N 5 %@ 1432-0533 %C Berlin %I Springer %M DKFZ-2017-05969 %P 705 - 714 %D 2017 %X Posterior fossa ependymomas (EPN_PF) in children comprise two morphologically identical, but biologically distinct tumor entities. Group-A (EPN_PFA) tumors have a poor prognosis and require intensive therapy. In contrast, group-B tumors (EPN_PFB) exhibit excellent prognosis and the current consensus opinion recommends future clinical trials to test the possibility of treatment de-escalation in these patients. Therefore, distinguishing these two tumor subtypes is critical. EPN_PFA and EPN_PFB can be distinguished based on DNA methylation signatures, but these assays are not routinely available. We have previously shown that a subset of poorly prognostic childhood EPN_PF exhibits global reduction in H3K27me3. Therefore, we set out to determine whether a simple immunohistochemical assay for H3K27me3 could be used to segregate EPN_PFA from EPN_PFB tumors. We assembled a cohort of 230 childhood ependymomas and H3K27me3 immunohistochemistry was assessed as positive or negative in a blinded manner. H3K27me3 staining results were compared with DNA methylation-based subgroup information available in 112 samples [EPN_PFA (n = 72) and EPN_PFB tumors (n = 40)]. H3K27me3 staining was globally reduced in EPN_PFA tumors and immunohistochemistry showed 99 %F PUB:(DE-HGF)16 %9 Journal Article %$ pmid:28733933 %2 pmc:PMC5647236 %R 10.1007/s00401-017-1752-4 %U https://inrepo02.dkfz.de/record/130893