COX4I1 and glioblastoma: To address the clinical relevance of our above findings, we examined the expression of COX4-1 and SC assembly in a panel of six of the GBM specimens with MGMT promoter methylation: three specimens from patients with high CcO activity and short overall survival (OS; mean CcO activity, 10.88 ± 1.00; mean OS, 134 days) and three specimens from patients with low CcO activity and long OS (mean CcO activity, 1.66 ± 0.22; mean OS, 691 days; Fig. 9A and B).