MGMT and glioblastoma: The path to the era of personalized medicine in GBM was first paved by the recognition of O6-methylguanine-DNA methyltransferase (MGMT) hypermethylation as a valid prognostic and predictive marker in patients undergoing treatment with temozolomide.9 Subsequent progress in this era of molecularly targeted strategies has been characterized by promising discoveries, with a failure to translate to clinically meaningful improved outcomes for patients.