GPR171 is a G protein-coupled receptor that binds the neuropeptide BigLEN, derived from the proSAAS precursor protein 1. The receptor functions through Gi-alpha-mediated signaling pathways to regulate diverse physiological processes 2. In immune regulation, GPR171 acts as a negative regulator of T cell activation by suppressing TCR-mediated signaling pathways and inhibiting T cell proliferation, thereby limiting antitumor immunity 1. The receptor also restrains intestinal inflammation by suppressing Th17 cell differentiation through the cAMP-pCREB-FABP5 axis and modulating lipid metabolism 3. In cancer biology, GPR171 is overexpressed in 46.8% of lung carcinomas and promotes tumor cell proliferation, migration, and invasion 4. Additionally, GPR171 plays a critical role in embryonic development by regulating hematopoietic stem cell emergence through ERK1/2 and Notch signaling pathways 5. During Helicobacter pylori infection, HIF-1α-induced GPR171 expression mediates CCL2 secretion by mast cells, promoting gastric inflammation 6. The receptor is also implicated in pain mechanisms and represents a potential therapeutic target for pain, anxiety, and body weight regulation 27.