FGFR1 is a receptor tyrosine kinase that serves as a cell-surface receptor for fibroblast growth factors, playing essential roles in embryonic development, cell proliferation, differentiation, and migration. Upon ligand binding, FGFR1 activates multiple signaling cascades, including phosphorylation of FRS2, which recruits GRB2 and triggers RAS/MAPK and AKT1 pathway activation, as well as PLCγ1-mediated signaling 1. The receptor localizes to both the cell surface and nucleus, with nuclear localization contributing to transcriptional regulation 2. FGFR1 is critical for normal mesoderm patterning, skeletogenesis, and GnRH neuronal system development; FGF8-FGFR1 signaling regulates human GnRH neuron differentiation in a dose- and time-dependent manner 2, and FGFR1 mutations are a major genetic cause of idiopathic hypogonadotropic hypogonadism 3. Beyond developmental roles, FGFR1 function has important pathological implications: endothelial FGFR1 loss promotes atherosclerosis progression through endothelial-to-mesenchymal transition 4, while macrophage-derived FGFR1 drives atherosclerosis via PLCγ-NF-κB inflammatory signaling 1. In lung cancer, FGFR1 overexpression correlates with increased gene copy numbers in squamous cell carcinoma and represents a therapeutic target 5. FGFR1 signaling is negatively regulated by Sprouty2-mediated ubiquitination and endocytosis 6.