OXTR encodes a 7-transmembrane G protein-coupled receptor located on chromosome 3 that mediates oxytocin signaling through Gαi/Gαq protein activation of phosphatidylinositol-calcium second messenger systems 1. The receptor activates multiple signaling cascades including MAPK, PKC, PLC, and CaMK pathways converging on transcription factors like CREB and MEF-2, regulating neurite outgrowth, cellular viability, and survival 1. Peripherally, OXTR governs reproduction through milk let-down, uterine contraction during labor, and maternal behaviors 1. Centrally, OXTR mediates social bonding, pair bonding, anxiety regulation, and stress response through oxytocinergic projections connecting the hypothalamus, amygdala, and prefrontal cortex 1. OXTR polymorphisms, particularly rs53576, associate with social-emotional functioning and behavioral outcomes in children and adolescents, with strongest evidence for autism spectrum disorder and conduct disorder links 2. DNA methylation of OXTR regulates social perception and stress reactivity; increased methylation correlates with social-cognitive deficits and callous-unemotional traits, while decreased methylation associates with anxiety and mood disorders 3. Notably, OXTR activates the Hippo/YAP axis driving hepatocellular carcinoma progression, and OXTR antagonist atosiban shows therapeutic promise for HCC treatment 4. Thus, OXTR functions as a pleiotropic regulator integrating reproductive physiology, social behavior, and pathological oncogenic signaling.