PIK3R1 and glioma: Less common genetic drivers of NF1-associated high-grade gliomas included TP53 mutation (3/17, 18%), PIK3CA or PIK3R1 mutation (4/17, 24%), PTEN mutation (1/17, 6%), PDGFRA amplification (1/17, 6%), MYCN amplification (1/17, 6%), PPM1D mutation (1/17, 6%), and SETD2 mutation (1/17, 6%).