PDGFRA and astrocytoma (excluding glioblastoma): Even when considering generally higher PDGFRA expression in IDHmut astrocytomas than in IDHwt GBs (Additional file 2: Fig. S3c), only a subpopulation of tumors with gene amplification represented outlier expression levels (in IDHmut astrocytomas, four tumors with PDGFRA amplification, three of which were grade 4).