To test the effects of the H3.3K27M mutation on the bound fractions of Ezh2 and Cbx7 in more physiologically relevant conditions, we stably expressed HaloTag-Ezh2 and HaloTag-Cbx7 in a DIPG patient-derived tumor cell line (SF8628) containing the heterozygous H3.3K27M mutation and in a control brain tumor cell line (9427)22. The gene discussed is CBX7; the disease is brain neoplasm.