MGMT and neoplasm: In the multivariate Cox analysis, MGMT promoter methylation status [unmethylated vs. methylated, P = 0.002, HR = 3.560 (1.600–7.920)] and tumor type [primary vs. recurrent/secondary, P = 0.010, HR = 0.384 (0.186–0.794)] remained significantly correlated with OS (Table 3).