Papillary glioneuronal tumor (PGNT) exhibits a characteristic methylation profile and fusions involving PRKCA
Hou Y, Pinheiro J, Sahm F, Reuss DE, Schrimpf D, Stichel D, Casalini B, Koelsche C, Sievers P, Wefers AK, Reinhardt A, Ebrahimi A, Fernández-Klett F, Pusch S, Meier J, Schweizer L, Paulus W, Prinz M, Hartmann C, Plate KH, Reifenberger G, Pietsch T, Varlet P, Pagès M, Schüller U, Scheie D, de Stricker K, Frank S, Hench J, Pollo B, Brandner S, Unterberg A, Pfister SM, Jones DTW, Korshunov A, Wick W, Capper D, Blümcke I, von Deimling A, Bertero L.
Acta Neuropathol. online article
Papillary glioneuronal tumor (PGNT) is a WHO-defined brain tumor entity that poses a major diagnostic challenge. Recently, SLC44A1-PRKCA fusions have been described in PGNT. We subjected 28 brain tumors from different institutions histologically diagnosed as PGNT to molecular and morphological analysis. Array-based methylation analysis revealed that 17/28 tumors exhibited methylation profiles typical for other tumor entities, mostly dysembryoplastic neuroepithelial tumor and hemispheric pilocytic astrocytoma. Conversely, 11/28 tumors exhibited a unique profile, thus constituting a distinct methylation class PGNT. Neither of the fusions was found in the tumors belonging to other methylation classes. Our results point towards a high misclassification rate of the morphological diagnosis PGNT and clearly demonstrate the necessity of molecular analyses. PRKCA fusions are highly diagnostic for PGNT, and detection by RNA sequencing enables the identification of rare fusion partners. Methylation analysis recognizes a unique methylation class PGNT irrespective of the nature of the PRKCA fusion.
