Glioma
This group comprises anaplastic astrocytomas and glioblastoma multiforme. Whereas the median overall survival of anaplastic (WHO grade III) gliomas is approximately 3 years, glioblastoma multiforme has a poor median overall survival of c. 15 months.
Glioblastoma
Another important alteration is methylation of MGMT, a "suicide" DNA repair enzyme. Methylation is described to impair DNA transcription and therefore, expression of the MGMT enzyme. Since an MGMT enzyme can repair only one DNA alkylation due to its suicide repair mechanism, reverse capacity is low and methylation of the MGMT gene promoter greatly affects DNA-repair capacity. Indeed, MGMT methylation is associated with an improved response to treatment with DNA-damaging chemotherapeutics, such as temozolomide.