PIK3CA and glioma: The frequency of IDH1, TP53, and ATRX mutations was significantly higher in gliomas with low risk score than those with high risk score (IDH1, 87% vs. 8%; TP53, 38% vs. 30%; ATRX, 24% vs. 10%), while the mutation frequency of TTN, PIK3CA, and MUC16 was significantly lower (TTN, 8% vs. 24%; PIK3CA, 6% vs. 11%; MUC16, 3% vs. 15%).