Glioblastoma
The most common length of survival following diagnosis is 12 to 15 months, with fewer than 3% to 5% of people surviving longer than five years. Without treatment survival is typically 3 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.