CDKN2A and malignant peripheral nerve sheath tumor: In MPNST, S100, SOX10, and H3K27me3 are often lost (Figure 14C); p16/CDKN2A is also lost (but this is also the case in some ANNUBP); TP53 may be diffusely positive in high-grade cases; and Ki67 is greater than 10% [170].