Mutations in the cell cycle G1 phase genes CDKN2A/2B, CDK4, and RB1 were mutually exclusive in this series, except for two heterozygous germline RB1 point mutations, and were present in 79.3% of glioblastoma IDH-wild-type cases (Table 1 and Figure 1E). The gene discussed is RB1; the disease is glioblastoma.