AATF (apoptosis antagonizing transcription factor) is a multifunctional protein with primary roles in ribosome biogenesis, transcriptional regulation, and stress response. As a component of the small subunit processome, AATF facilitates pre-rRNA processing and ribosomal RNA synthesis by interacting with RNA polymerase I and the nucleolar upstream binding factor (UBF), while modulating rDNA promoter epigenetics through HDAC1 displacement 1. AATF regulates cell cycle progression by displacing HDAC1 from RB/E2F complexes to promote proliferation, and from SP1-bound CDKN1A promoters to induce growth arrest 2. Beyond transcription, AATF protects cells from multiple stress stimuli (DNA damage, ER stress, hypoxia) by facilitating non-homologous end-joining DNA repair through XRCC4 stabilization 3. Clinically, AATF is significantly overexpressed in multiple cancers including bladder cancer, head and neck squamous cell carcinoma, and glioblastoma, where it promotes therapeutic resistance and poor prognosis by upregulating anti-apoptotic proteins like survivin and suppressing chemotherapy-induced apoptosis 4, 5, 3. Recent evidence indicates AATF cooperates with metabolic enzymes to regulate immune evasion in pancreatic neuroendocrine tumors 6. These diverse functions establish AATF as both a critical cellular regulator and promising therapeutic target.