DRD2 encodes dopamine receptor D2, a G-protein-coupled receptor that inhibits adenylyl cyclase activity 1. Beyond classical dopaminergic signaling, DRD2 exhibits pleiotropic functions across multiple physiological systems. In cancer biology, DRD2 functions as a tumor suppressor in breast cancer, where its expression is frequently reduced through promoter methylation 2. DRD2 suppresses tumorigenesis by restricting NF-κB signaling through interactions with β-arrestin2, DDX5, and eEF1A2, while promoting M1 macrophage polarization and triggering GSDME-mediated pyroptosis 2. In glioblastoma, elevated dopamine and DRD2 paradoxically accelerate progression via ERK/β-catenin activation and a dopamine/ERK/TH positive feedback loop, with chr11 stress exacerbating this pathology 3. DRD2 is implicated in neuropsychiatric disorders. Genetic association studies demonstrate that C957T polymorphism increases schizophrenia risk, particularly in Caucasians 4, while hypermethylation and reduced DRD2 expression associate with schizophrenia pathology 5. The DRD2 gene is necessary for social functioning across evolutionary distant species; D2R autoreceptor activation on dopaminergic neurons regulates sociability 6. Clinically, DRD2 status predicts treatment response; higher expression correlates with improved survival and paclitaxel sensitivity in HER2-positive breast cancer 2, and DRD2 inhibition synergizes with temozolomide in glioblastoma 3.