H3K27me3 is an important type of transliteration inhibitory translation modification. It mainly exists in the promoter of gene -dense areas and plays a role in all aspects of the biological process with the development regulatory factors in the embryo stem cells. H3K27me3 is lacking in the expression of about 50% malignant peripheral nerve sheath tumor （MPNST）, and the nerve sheath tumor is positive. In pathology, it is mainly used in the differentiated diagnosis of malignant peripheral nerve sheath tumors, especially high level malignant peripheral nerve sheath tumors （lack of expression） and similar tumors.