IDH1 and central nervous system cancer: evaluated RNA‐sequencing (RNA‐seq), somatic mutation, and clinical data from 1052 low‐grade glioma (LGG) from the cancer genome atlas (TCGA) and Chinese glioma genome atlas (CGGA), and illustrated a gradual decrease in expression of several human leukocyte antigen (HLA) genes encoding the MHC class I proteins from the IDH‐wildtype to IDH‐mutant 1p/19q co‐deleted (current WHO nomenclature is oligodendroglioma IDH‐mutant and 1p/19q‐codeleted), with IDH‐mutant non‐co‐deleted (current WHO nomenclature is astrocytoma IDH‐mutant) occupying an intermediate position in this expression pattern.