In these recurrent/residual high grade gliomas with changes in SETD2, longer durations of follow-up were seen after initial presentation (mean of 79 and 42 months for IDH-mutant tumors and 52.5 ± 12.0 months for IDH-wildtype tumors) than is common for high grade gliomas. This evidence concerns the gene IDH1 and central nervous system cancer.