TP53 and central nervous system cancer: In keeping with the notion that co-occurrence of IDH1 hotspot mutation and TP53 alteration is glioma-specific, the mean co-occurrence frequency was fivefold greater in glioma than in non-glioma (Figure 4A); however, the difference in IDH1R132H co-occurrence frequencies between glioma and non-glioma was not statistically significant (Figure 4B), even though IDH1R132H occurred in 92% in lower-grade glioma harboring IDH1 hotspot mutations [13].