Since the publication of the first marker paper, several analysis groups within the TCGA Network have presented more detailed analysis of the glioblastoma data. An analysis group led by Roel Verhaak, PhD, Katherine A. Hoadley, PhD, and D. Neil Hayes, MD, successfully correlated glioma gene expression subtypes with genomic abnormalities. The DNA methylation data analysis team, led by Houtan Noushmehr, PhD and Peter Laird, PhD, identified a distinct subset of glioma samples which displays concerted hypermethylation at a large number of loci, indicating the existence of a glioma-CpG island methylator phenotype (G-CIMP). G-CIMP tumors belong to the proneural subgroup and were tightly associated with IDH1 somatic mutations.