In the single-arm, phase 2 RTOG 0424 study of patients with either IDH-mutant or IDH-wild-type “high-risk” low-grade glioma receiving RT plus concurrent and adjuvant TMZ, median survival time of 8.2 years and 10-year survival rate of 34.6% were superior to those observed in historical controls treated with RT alone [5]. Here, IDH1 is linked to glioma.