Moreover, given that elderly GBM patients are heterogeneous, with various responses to therapies, a combination of performance status, the extent of resection, comorbidity, clinically relevant biomarkers (e.g., MGMT promoter status) and chronological age should be investigated in future trials to help stratify older patients for optimal individualized treatment, along with a standardized assessment of toxicity and HRQOL. The gene discussed is MGMT; the disease is glioblastoma.