We utilized a previously described genetically engineered mouse model (GEMM) that develops spontaneous and highly penetrant brainstem high-grade gliomas with K27M/p53/PDGFα driver mutations following postnatal induction.10 We treated MRI-confirmed tumor-bearing GEMM animals with alisertib (20 mg/kg) by daily oral lavage. Here, TP53 is linked to central nervous system cancer.