There were two apparent subclusters within the high-grade IDH-mutant astrocytoma grouping, one containing the original resection (sample 1) and recurrent tumor masses from the corpus callosum and left hemisphere (samples 5, 6, 7, and 8), and a second group containing the recurrent tumor masses adjacent to the original resection in the right hemisphere, and the midbrain (samples 2, 3, 4, and 9). This evidence concerns the gene IDH2 and astrocytoma (excluding glioblastoma).