MGMT and glioblastoma: Since increased resistance to chemotherapy is also an essential hallmark of stem-like GBM cells, both pure cultures of patient-derived GSCs and more differentiated GBM cells (both with a methylated MGMT-promotor) were treated with 50 μM Temozolomide (TMZ; concentration nearly equivalent to that observed in human cerebrospinal fluid after oral administration34) 48 h after mFUS pretreatment (AIP 5 and 11 W) for a total of 10 additional days, and the cytotoxic effect of TMZ with or without mFUS pretreatment was tested.