EED
Overview
EED (Embryonic Ectoderm Development) encodes a core structural component of the Polycomb Repressive Complex 2 (PRC2), which catalyzes H3K27 trimethylation to silence developmental genes. In malignant peripheral nerve sheath tumors (MPNSTs), EED is frequently inactivated via loss-of-function mutations, establishing PRC2 as a tumor suppressor in this sarcoma subtype.
Alterations observed in the corpus
- Loss-of-function mutations (4 frameshift, 1 splice-site) with LOH (heterozygous deletion or copy-neutral LOH) in MPNST discovery cohort; mutually exclusive with SUZ12 alterations PMID:25240281.
- EED and SUZ12 alterations collectively inactivate PRC2 in 92% of sporadic, 70% of NF1-associated, and 90% of radiotherapy-associated MPNSTs PMID:25240281.
Cancer types (linked)
- MPNST: highly recurrent loss-of-function alterations (80% of discovery cohort, up to 92% in sporadic cases); H3K27me3 loss by IHC tracks PRC2 functional status and distinguishes MPNST from benign neurofibromas PMID:25240281.
Co-occurrence and mutual exclusivity
- Mutually exclusive with SUZ12 alterations within the same tumor PMID:25240281.
- Significantly co-occurs with NF1 and CDKN2A alterations (Fleiss’ kappa=0.21, p=0.001) PMID:25240281.
Therapeutic relevance
- Because PRC2 (EED/SUZ12) acts as a tumor suppressor in MPNST (contrast with EZH2 oncogenic gain-of-function in lymphoma), broad PRC2 inhibitors are unlikely to benefit; downstream PRC2-repressed pathways may be therapeutically targetable PMID:25240281.
Open questions
- Whether EED-deficient MPNSTs respond equivalently to SUZ12-deficient tumors in functional rescue experiments remains untested PMID:25240281.
Sources
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