EPC1 (enhancer of polycomb 1) is a non-catalytic component of the NuA4/TIP60 histone acetyltransferase complex that functions as a master regulator of transcription and DNA repair. Within the complex, EPC1 recruits MBTD1 through a distinct hydrophobic interaction domain 1, facilitating histone H4 and H2A acetylation at target genes 2. EPC1 plays a direct role in homologous recombination-mediated DNA double-strand break repair by promoting NuA4-dependent histone modifications that block 53BP1 binding 1. Beyond its canonical chr10 remodeling functions, EPC1 exhibits oncogenic activity in multiple cancer types. In cancer cells, EPC1 physically interacts with transcription factor E2F1 to suppress pro-apoptotic genes (like TP53 targets) while activating anti-apoptotic survival genes (BCL-2, Survivin) and metastasis-related signatures 3. EPC1 is significantly upregulated in nasopharyngeal carcinoma tissues and cell lines, where EPC1 knockdown inhibits proliferation, invasion, and epithelial-mesenchymal transition 4. Similarly, EPC1 sustains leukemia stem cell potential in MLL-mutated acute myeloid leukemia by preventing MYC protein accumulation 5. EPC1 mutations are recurrently identified in pancreatic ductal adenocarcinoma 6, supporting its established pro-cancer role across multiple malignancies.