{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Trimethylation of lysine 27 on histone H3 protein (H3K27me3) is an epigenetic modification associated with heterochromatin formation and gene silencing. EZH2, an enzymatic component of the polycomb repressive complex 2 (PRC2) is responsible for adding methyl groups to lysine 27 on histone H3 protein. As a gene transcription repressor, H3K27me3 has diverse roles in embryogenesis and neoplasia. According to literature, loss of H3K27me3 occurs in a significant subset of malignant peripheral nerve sheath tumors. Other neoplasms also show loss of H3K27me3 expression or heterogenous expression."}]}]}