K27M mutations in histone H3 genes, most commonly in H3-3A (4.3% of glioma samples), indicate diffuse midline glioma, H3-3A G34R mutations (1.4% of samples) hemispheric glioma,27 and BRAF fusions (2.8%) pilocytic astrocytoma.28 In other cancer types, CDH1 alterations are characteristic of lobular breast cancer29 or hereditary diffuse-type gastric cancer.30GNA11 or GNAQ hotspot mutations may be of diagnostic value for uveal (49.3% and 44.4%, respectively) or blue nevi-related melanomas (1.8% of melanomas each).31,32. The gene discussed is CDH1; the disease is diffuse midline glioma.