Of 66 F3T3 gliomas with high-grade histology, which were profiled for DNA methylation in three different studies, 54 matched the methylation class glioblastoma “IDH-wildtype” and 12 did not match any classes, using version 11b4 of the Heidelberg classifier [11,12,28]. The gene discussed is IDH1; the disease is glioblastoma.