MGMT and glioblastoma: While MGMT methylation status was not associated with cortical, WM or deep grey matter nuclei involvement, the MGMT methylation percentage, among MGMT-methylated patients, positively correlated with the percentage of GBM core overlapping the cortical grey matter (R = 0.36, P = 0.021; see Fig. 2) and negatively correlated with the involvement of deep grey matter nuclei (R = −0.35, P = 0.025; see Fig. 2), while it was not significantly associated with the WM involvement percentage (R = −0.21, P = 0.19).