Fig 1: Kaplan-Meier survival curves for progression-free survival (PFS) according to VDR protein expression (A) and multivariable Cox proportional hazards model adjusted for age, sex, and MGMT promoter methylation (B). Scatter plot showing the association between VDR mRNA expression (fold change) and VDR protein levels (nmol/L). Each dot represents one patient sample, with dot size proportional to plasma 25(OH)D concentration (C). VDR, vitamin D receptor; MGMT, O6-methylguanine-DNA methyltransferase; 25(OH)D, 25-hydroxyvitamin D; Low, low VDR protein expression; High, high VDR protein expression.