Diffuse midline glioma (DMG)is a lethal childhood brain cancer with poor treatment options. Thus far no drugs have been approved and the treatment remains radiation therapy which only slows the disease. We now understand that the defect in these tumors is an 'epigenetic' problem, an error in the systems which switch genes on and off (called polycomb proteins). In DMG, certain genes are inappropriately switched off and we need to find better ways to switch them on so the tumor stops growing. In this proposal we have found a new way to switch these genes on and we want to study this so we can eventually do a clinical trial in children with this disease.