Taking advantage of a previously established line of Ezh2flox/flox immortalized mouse embryonic fibroblasts (iMEFs)32, we used inducible Cre recombinase to delete Ezh2 and CRISPR/Cas9-mediated gene editing to delete Eed or introduce the H3.3K27M substitution (Supplementary Fig. 1a, b), thereby modeling mutations found in hematological malignancies, MPNST and diffuse midline glioma, respectively. Here, EED is linked to diffuse midline glioma.