TP53 and brainstem neoplasm: To test this, murine PDGF-B; H3.3-K27M; p53-deficient brainstem tumors were induced as described above, and upon the first appearance of brain tumor symptoms, mice were treated with three doses of 10mg/kg panobinostat or vehicle once daily via i.p. injections and then sacrificed 1 hour after the final treatment (n = 5 in each group).