More importantly, our data also suggest that changing molecular features (including MGMT promoter methylation and other key markers of aggressiveness and treatment responsiveness in diffuse gliomas) may be missed in the routine analysis of single biopsy or resection samples and that whole-genome methylation profiling and copy number profiling in multiple samples may provide useful information in the case of tumor recurrence to identify potentially useful changing molecular milieu. Here, MGMT is linked to neoplasm.