ARID4A is a DNA-binding protein that functions as a transcriptional co-regulator with dual roles in both repression and activation depending on cellular context 1. It operates within SIN3-histone deacetylase chr14 remodeling complexes and interacts with retinoblastoma protein (RB1) and other regulatory proteins 1. ARID4A regulates epigenetic modifications at the PWS/AS imprinting center through histone methylation and DNA methylation changes 2. Functionally, ARID4A acts as a tumor suppressor across multiple cancer types. In breast cancer, it suppresses metastasis by stabilizing mRNA transcripts of metastasis-suppressing genes including MTSS1, TIMP2, RB1, and PTEN through binding conserved 3'UTR elements 3. In prostate cancer, downregulation of ARID4A correlates with poor prognosis, high Gleason scores, and enhanced cell proliferation and invasion 4. ARID4A was also identified as a candidate neurodegeneration suppressor in ALS-FTD models, with downregulation associated with improved behavioral outcomes 5. Recently, ARID4A was identified as a novel nucleosome-binding protein 6. A schizophrenia-associated missense variant (p.His411Asp) impairs DNA-binding capacity and cell cycle regulation 7. These findings establish ARID4A as a multifunctional epigenetic regulator with therapeutic potential in cancer and psychiatric disorders.