DNA sequencing of the tumor revealed the H3K27M mutation in HIST1H3B (Figure 1H, left), a rare mutation variant in histone, and G328E mutation in ACVR1 (Figure 1H, right), a frequently encountered mutation in patients with DIPGs with HIST1H3B mutation (10, 33, 35). The gene discussed is ACVR1; the disease is neoplasm.