Multivariate analysis identified “age > 65 years” (p < 0.0001, OR 6.4, 95% CI 3.3–12.3), “STR” (p = 0.001, OR 3.2, 95% CI 1.6–6.1), “unmethylated MGMT status” (p < 0.001, OR 3.3, 95% CI 1.7–6.4), and “perioperative RBC transfusion” (p = 0.01, OR 6.0, 95% CI 1.5–23.4) as significantly and independently associated with 1-year mortality, whereas tumor volume did not in patients who had undergone glioblastoma surgery (Nagelkerke’s R2 0.37). The gene discussed is MGMT; the disease is glioblastoma.