The M3/38 monoclonal antibody specifically recognizes Galectin-3 (Gal-3 or gal3) which is also known as Galactose-specific lectin 3, Mac-2, MAC2, and Carbohydrate-binding protein 35 (CBP 35). Galectin-3 is an ~30-35 kDa protein that includes an N-terminal proline-rich tandem repeat domain as well as a C-terminal region with one carbohydrate recognition domain (CRDs). Galectin-3 is encoded by Lgals3 (lectin, galactose binding, soluble 3) which belongs to the galectin family. It is expressed by a variety of cells including activated macrophages, dendritic cells (DCs), granulocytes, mast cells, and epithelial cells. Galectin-3 can be detected in monomeric or multimeric forms in cytoplasmic, nuclear, cell surface and extracellular locations. Galectin-3 is a β-galactoside-binding lectin that has multiple intracellular and extracellular functions implicated in biological processes including RNA splicing as well as cellular chemoattraction and adhesion, activation, growth, proliferation, differentiation, and apoptosis. Upregulated Galectin-3 expression is implicated in inflammation and disease states including cancer progression and metastasis.