(B) Methylation arrays of primary glioblastoma (GBM) specimens revealed that CpG island 1 (egfl7 promoter) was mostly unmethylated with the exception of some samples in the RTKII subgroup (*). CpG island 2 (miR-126 promoter) was found methylated in most cases except the G34R subgroup (**). G34R and K27M - GBMs with mutations in a gene for the H3.3 histone variant; RTKI and II - GBMs with a mutation in the receptor tyrosine kinase type I (proneural subtype) and II (classical subtype); MES - GBMs with a deleterious mutation in the NF1 gene (mesenchymal subtype); IDH1 - GBMs with a mutation in isocitrate dehydrogenase 1 