MGMT (O-6-Methylguanine-DNA Methyltransferase): MGMT is a DNA repair enzyme that removes alkyl groups from the O6 position of guanine, helping to prevent mutations and maintain genomic stability. It protects cells from the harmful effects of alkylating agents and is a key factor in resistance to certain chemotherapy drugs. In cancers such as gliomas, MGMT expression can influence treatment response and is a significant focus of cancer research.