IDH1 and central nervous system cancer: Herein, we refer to “high‐risk lower grade gliomas (LGG)” as a category encompassing patients who were largely WHO 2016 IDH1 mutant anaplastic gliomas (WHO 2007 grade III anaplastic oligodendroglioma or anaplastic mixed oligoastrocytoma) and grade II gliomas of any histology with unfavorable features (eg, age > 40, subtotal resection, tumor crossing midline).5, 6