MGMT methylated is when the genetics responsible for a type of brain tumor called a glioblastoma have been altered by a chemical process called methylation. A MGMT methylated glioblastoma allows for a better patient response to treatments, specifically temozolomide and radiation.
MGMT (O6-methylguanine-DNA methyltransferase) is a special enzyme that can repair damaged DNA. While MGMT protects normal cells, it, unfortunately, also protects tumor cells from chemotherapy. Specifically, the MGMT enzyme can rescue tumor cells from damage by alkylating agents, which are active in certain treatments and make tumors resistant to chemotherapy. In glioblastoma, present MGMT enzymes catalyze the transfer of methyl groups and maintain the methylation pattern during DNA transcription—these patterns have been associated with tumor replication and progression in several cancers.
Silencing the MGMT gene by the process of methylation reduces any repair activity and increases the tumor’s sensitivity to therapy. Tests can determine whether a patient is MGMT methylated or MGMT unmethylated. It is thought that the methylated status of the MGMT gene (after a methyl group has been transferred) can predict a better responsiveness to therapy. While the test should be considered in the context of other clinical findings, recognizing the MGMT gene and its methylation status reveals a significant biomarker that is especially relevant when guiding patients in therapeutic decision-making—particularly in elderly patients—and can prevent unnecessary treatments and costs.