CDKN2A and glioblastoma: Whole-genome sequencing confirmed the four tumor foci harbored typical genetic features of GBM (Supplementary Fig. S3e), including gain and loss of chromosome 7 and 10, respectively, and loss of key tumor suppressors PTEN and CDKN2A/2B.18,21 In addition, we observed the amplification of EGFR and PDGFA in all tumor foci and amplification of PDGFRA gene in tumor sample 2 and 3.