NF1 and neurofibroma: Lee et al.33 found loss of PRC2 function (through SUZ12 or EED mutation) in over 70% of MPNSTs (regardless of NF1 disease status), and showed that this resulted in loss of H3K27 trimethylation (H3K27me3), a repressive epigenetic histone modification, which correlated with transcriptional alterations in 479 genes, such as upregulation of IGF2, PAX2, and TLX1. A 2016 study screened 162 MPNSTs for H3K27me3 by immunohistochemistry, finding loss in 34% of MPNSTs, compared to none in neurofibromas.70 Patients with tumor loss of H3K27me3 also had a poorer prognosis.