MGMT and glioblastoma: Multivariate analysis indicated that total protein (HR = 0.978, 95%CI: 0.960–0.998, p = 0.029), prealbumin levels (HR = 0.997, 95%CI: 0.993–1.000, p = 0.041), and MGMT promoter methylation (HR  = 0.618, 95% CI: 0.387–0.988, p = 0.044) were independently associated with OS in GBM patients.