LGALS1 (galectin-1) is a β-galactoside-binding lectin that functions as a critical immunomodulator and regulator of cell fate across multiple disease contexts. The protein binds complex carbohydrates and regulates apoptosis, cell proliferation, and T-cell differentiation by inhibiting CD45 phosphatase activity and suppressing Th17 cell lineage commitment 1. In acute myeloid leukemia, LGALS1 is upregulated in quiescent stem-like cells and mediates chemoresistance; LGALS1 inhibition eliminates chemoresistant cells and enhances therapeutic sensitivity 2. LGALS1 expression in leukemia stem cells correlates with poor prognosis and supports stemness through lipid metabolism remodeling; its repression inhibits proliferation and increases apoptosis 3. In solid tumors, LGALS1 functions as a key immunosuppressive regulator—glioblastoma-associated macrophages express LGALS1 to promote tumor immunosuppression 4, while in esophageal cancer, serum galectin-1 mediates paclitaxel resistance via Wnt/β-catenin pathway activation and MDR1 upregulation; targeting LGALS1 restores drug sensitivity 5. In cholangiocarcinoma, LGALS1+ cancer-associated fibroblasts promote tumor cell proliferation and migration 6. Additionally, LGALS1 functions in lysosomal membrane permeabilization detection 7 and protects against atherosclerosis by maintaining vascular smooth muscle cell contractility 8.