Comment by wpietri

That may be a different and much harder problem. Glioblastoma is an aggressive brain cancer and that diagnosis is basically a death sentence, with a median survival time of something like 15 months. Since these are patients with recurrent glioblastoma, generally this means they've already had brain surgery, radiation, and chemo. At that point, as a recent paper puts it, "treatment options are limited and management of recurrent glioblastoma remains challenging". Which I believe is oncologist for "they're fucked". So my guess is that this is the beginning of a long road of searching for agents and regimens that will be deadly enough to kill the tumor without harming the very similar brain tissue that it's nestled in.