- OMIM: 156569
- UniProt: P16455
- MGI: 96977
O6 -methylguanine - DNA methyltransferase ( MGMT ) (also 6-O- methylguanine - DNA methyltransferase or Methylated DNA -cysteine -S -methyl ) is a protein within the nucleus which is involved in the repair of alkylated DNA. MGMT is formed in all living things. Inactivation of the MGMT gene leads to tumor formation.
In addition to the beneficial functions that have the methylation of DNA, are the harmful effects exerted by methylating agents on the DNA, in particular the formation of 6-O- methylguanine of guanine in the DNA, resulting in the formation of tumors. The repair of this defect is accomplished by MGMT by transferring the methyl group to itself. Since MGMT is consumed in this reaction, it is strictly speaking not an enzyme.
The detection of epigenetic changes in the MGMT promoter ( hypermethylation ) is associated with a better prognosis and a better response to chemotherapy with alkylating agents such as temozolomide in glioblastoma.