Fibroblast growth factors (FGFs) are a family of small, glycosylated proteins that play crucial roles in cellular signaling. The human genome contains 29 potential FGF genes, with 23 having identified transcripts. FGFs are involved in various signaling pathways, including the Ras/MAP kinase pathway, which is essential for many cellular responses. FGF signaling requires a sulphated glycosaminoglycan (GAG) co-factor and involves receptor tyrosine kinases. FGFs activate multiple signaling cascades, such as the PI 3-kinase pathway and the inositol lipid/calcium pathway, through interactions with proteins like Grb2–Sos, Gab1, and phospholipase C-γ. Feedback regulation involves transmembrane proteins, tyrosine phosphatases, and Sef proteins, which modulate receptor activity and the Ras/MAP kinase pathway. Alternative splicing of FGF receptor RNAs can alter receptor specificity and generate secreted extracellular domains that function as competitive inhibitors. FGFs are implicated in numerous biological processes, including cell proliferation, apoptosis, differentiation, and development. They are also involved in disease, such as oncogenesis and angiogenesis, and mutations in FGF receptors are linked to several syndromes. While FGFs are mitogens for some cell lines, primary fibroblasts may not respond to them. FGFs are essential for development, including mesoderm and neural induction, limb outgrowth, and brain patterning. They can enter the cell nucleus, though their nuclear functions are not fully understood. FGFs are complex, with multiple regulatory mechanisms and diverse functions in both normal and pathological conditions.Fibroblast growth factors (FGFs) are a family of small, glycosylated proteins that play crucial roles in cellular signaling. The human genome contains 29 potential FGF genes, with 23 having identified transcripts. FGFs are involved in various signaling pathways, including the Ras/MAP kinase pathway, which is essential for many cellular responses. FGF signaling requires a sulphated glycosaminoglycan (GAG) co-factor and involves receptor tyrosine kinases. FGFs activate multiple signaling cascades, such as the PI 3-kinase pathway and the inositol lipid/calcium pathway, through interactions with proteins like Grb2–Sos, Gab1, and phospholipase C-γ. Feedback regulation involves transmembrane proteins, tyrosine phosphatases, and Sef proteins, which modulate receptor activity and the Ras/MAP kinase pathway. Alternative splicing of FGF receptor RNAs can alter receptor specificity and generate secreted extracellular domains that function as competitive inhibitors. FGFs are implicated in numerous biological processes, including cell proliferation, apoptosis, differentiation, and development. They are also involved in disease, such as oncogenesis and angiogenesis, and mutations in FGF receptors are linked to several syndromes. While FGFs are mitogens for some cell lines, primary fibroblasts may not respond to them. FGFs are essential for development, including mesoderm and neural induction, limb outgrowth, and brain patterning. They can enter the cell nucleus, though their nuclear functions are not fully understood. FGFs are complex, with multiple regulatory mechanisms and diverse functions in both normal and pathological conditions.