Longitudinal epigenome analysis of IDH-wildtype glioblastomas from initial and recurrent surgical specimens

Genome-wide DNA methylation profiling of 226 longitudinally collected IDH-wildtype glioblastoma tumor specimens from 106 patients, consisting of 99 initial treatment-naive resection specimens prior to any radiation or chemotherapy and 127 recurrent post-treatment resection specimens at time of recurrence/progression usually following radiation and/or chemotherapy. These 127 recurrent post-treatment resection specimens were composed of 106 first surgically-treated recurrent specimens, 19 second surgically-treated recurrent specimens, and 2 third surgically-treated recurrent specimens. The Illumina Infinium EPIC 850k version 1.0 Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of the 226 IDH-wildtype glioblastomas. Bisulfite converted genomic DNA extracted from the 226 IDH-wildtype glioblastoma tumor samples was hybridized to Illumina Infinium EPIC 850k version 1.0 Human DNA Methylation Beadchips