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). The gene discussed is IDH2; the disease is neoplasm.