IDH2 and central nervous system cancer: We showed that IDH-wild-type primary and first recurrent tumors had the highest overall stemness index (medians of 0.23 and 0.2, respectively) compared with the entire IDH mutant cohort at primary and first recurrence (medians of 0.1 and 0.14, respectively); however, the degree of stemness within IDH-wild-type shifted from primary to first recurrence (p = 0.05) (Figure 2B), suggesting that IDH-wild-type recurrent gliomas may be defined by expansion of a resistant clone that is more differentiated yet aggressive in nature, as reported for metastatic melanoma cells (Cheli et al., 2011).