An exome analysis of eight NF1 MPNSTs found uniform inactivation of NF1; heterozygous or homozygous CDKN2A deletion in 63%; and SUZ12 or EED mutations in 87.5% of samples.34 Homozygous TP53 deletion was found in one MPNST, and another harbored a heterozygous missense mutation in KDM2B (a master regulator of polycomb complex PRC1) that was predicted to be deleterious. This evidence concerns the gene CDKN2A and malignant peripheral nerve sheath tumor.