The fact that the MGMT gene is silenced by promoter methylation in about 40% of gliomas and colorectal tumors, as well as in about 25% of NSCLCs, lymphomas, and head and neck cancers, suggests the significance of this enzyme, MGMT, as a DNA alkyltransferase, in the development of certain types of human tumors.95 The gene discussed is MGMT; the disease is glioma.