Galectin-1 (Gal-1) is a member of the galectin family, a group of carbohydrate-binding proteins that recognize β-galactosides. Gal-1 is expressed in various normal and pathological tissues and exhibits a wide range of biological activities. It plays a key role in immune responses, including T-cell homeostasis, survival, immune disorders, inflammation, allergies, and host-pathogen interactions. Gal-1 is also involved in tumor progression, tumor immune-escape, and the regeneration of the central nervous system after injury. Its extracellular activity is mainly dependent on its lectin activity, while its intracellular activity is independent of it. Gal-1 can exist in monomeric and dimeric forms, with the dimeric form being more stable. Gal-1 is secreted and can be found in the extracellular space, where it interacts with various cell surface molecules and extracellular matrix components. Gal-1 has been shown to modulate cell signaling pathways, including cell growth, migration, and invasion. It can also influence the immune system by modulating T-cell homeostasis, survival, and apoptosis. Gal-1 is involved in the regulation of inflammatory responses and has been shown to have therapeutic potential in the treatment of inflammation-related diseases, neurodegenerative pathologies, and muscular dystrophies. However, its overexpression in tumors is associated with poor prognosis and tumor immune-escape. Gal-1 is also involved in nerve regeneration, particularly in its oxidized form, which promotes neurite outgrowth and axonal regeneration. Gal-1's role in various biological processes makes it a promising molecular target for the development of new therapeutic strategies.Galectin-1 (Gal-1) is a member of the galectin family, a group of carbohydrate-binding proteins that recognize β-galactosides. Gal-1 is expressed in various normal and pathological tissues and exhibits a wide range of biological activities. It plays a key role in immune responses, including T-cell homeostasis, survival, immune disorders, inflammation, allergies, and host-pathogen interactions. Gal-1 is also involved in tumor progression, tumor immune-escape, and the regeneration of the central nervous system after injury. Its extracellular activity is mainly dependent on its lectin activity, while its intracellular activity is independent of it. Gal-1 can exist in monomeric and dimeric forms, with the dimeric form being more stable. Gal-1 is secreted and can be found in the extracellular space, where it interacts with various cell surface molecules and extracellular matrix components. Gal-1 has been shown to modulate cell signaling pathways, including cell growth, migration, and invasion. It can also influence the immune system by modulating T-cell homeostasis, survival, and apoptosis. Gal-1 is involved in the regulation of inflammatory responses and has been shown to have therapeutic potential in the treatment of inflammation-related diseases, neurodegenerative pathologies, and muscular dystrophies. However, its overexpression in tumors is associated with poor prognosis and tumor immune-escape. Gal-1 is also involved in nerve regeneration, particularly in its oxidized form, which promotes neurite outgrowth and axonal regeneration. Gal-1's role in various biological processes makes it a promising molecular target for the development of new therapeutic strategies.