FOXO4 is a transcription factor and member of the mammalian FOXO subfamily that functions as a key regulator of cellular stress adaptation and longevity 1. As a downstream effector of insulin signaling, FOXO4 binds insulin-response elements to regulate metabolic gene expression and controls diverse cellular processes including oxidative stress resistance, cell cycle regulation, and apoptosis 2. FOXO4 suppresses HIF1A expression and negatively regulates angiogenesis and cell proliferation, establishing it as a context-dependent tumor suppressor 3. The protein mediates stress response pathways critical for preserving cellular homeostasis and countering age-related functional decline 1. Clinically, FOXO4 dysregulation contributes to hematological malignancies through chrX fusion with the MLL gene 4. Conversely, therapeutic targeting of FOXO4 shows promise in eliminating senescent cells—dysfunctional cells that accumulate with age. FOXO4-disrupting peptides that perturb FOXO4-p53 interactions selectively induce senescent cell apoptosis, restoring tissue homeostasis in aging and chemotherapy-induced contexts 5. Similarly, FOXO4-targeted approaches reduce radiation-induced fibrosis and enhance cancer radiosensitivity by targeting senescence-like fibroblasts 6. Additionally, miR-328a-3p targets FOXO4 to promote osteogenic differentiation 7. These findings position FOXO4 as both a guardian of cellular health and a therapeutic target for age-related diseases.