Anaplastic astrocytoma with piloid features, a novel molecular class of IDH wildtype glioma with recurrent MAPK pathway, CDKN2A/B and ATRX alterations
Reinhardt A, Stichel D, Schrimpf D, Sahm F, Korshunov A, Reuss DE, Koelsche C, Huang K, Wefers AK, Hovestadt V, Sill M, Gramatzki D, Felsberg J, Reifenberger G, Koch A, Thomale UW, Becker A, Hans VH, Prinz M, Staszewski O, Acker T, Dohmen H, Hartmann C, Mueller W, Tuffaha MSA, Paulus W, Heß K, Brokinkel B, Schittenhelm J, Monoranu CM, Kessler AF, Loehr M, Buslei R, Deckert M, Mawrin C, Kohlhof P, Hewer E, Olar A, Rodriguez FJ, Giannini C, NageswaraRao AA, Tabori U, Nunes NM, Weller M, Pohl U, Jaunmuktane Z, Brandner S, Unterberg A, Hänggi D, Platten M, Pfister SM, Wick W, Herold-Mende C, Jones DTW, von Deimling A, Capper D.
Acta Neuropathol. online article
Tumors with histological features of pilocytic astrocytoma (PA), but with increased mitotic activity and additional high-grade features (particularly microvascular proliferation and palisading necrosis) have often been designated anaplastic pilocytic astrocytomas. The status of these tumors as a separate entity has not yet been conclusively demonstrated and molecular features have only been partially characterized. We performed DNA methylation profiling of 102 histologically defined anaplastic pilocytic astrocytomas. The most frequent localization was the posterior fossa (74%). Deletions of CDKN2A/B (66/83, 80%), MAPK pathway gene alterations (49/65, 75%, most frequently affecting NF1, followed by BRAF and FGFR1) and mutations of ATRX or loss of ATRX expression (33/74, 45%) were the most common molecular alterations. All tumors were IDH1/2 wildtype. The MGMT promoter was methylated in 38/83 tumors (45%). Outcome analysis confirmed an unfavorable clinical course in comparison to PA, but better than IDH wildtype glioblastoma.
