PIK3CA and glioma: In addition, wt-IDH1 gliomas can harbor alterations in regulators of the RTK-RAS-PI3K signaling cascade, including EGFR amplification, as well as mutations or deletions to tumor-suppressor genes PTEN and CDKN2A/B, and alterations to chromosomes 7 and 10 (12, 24, 25, 31).