IDH1 and glioma: Indeed, glioblastomas express IDH1 at higher levels compared to gliomas of lower grade (log2 expression levels of 10.9 ± 0.48 vs. 11.3 ± 0.49, vs. 11.4 ± 0.48 for grade II (n = 24), grade III (n = 85) and grade IV gliomas (n = 159) respectively [46]).