Galectin-3 (Gal-3) is a member of the galectin family of beta-galactoside-binding proteins, which is involved in both intracellular and extracellular functions and exhibits anti-apoptotic properties.

Gal-3 is implicated in many biological processes, including cell differentiation, growth, adhesion, angiogenesis and inflammation, and is expressed in a wide range of neoplasms. Gal-3 acts as a regulator of tumour metastasis, and several studies have shown a correlation between levels of Gal-3 and tumour progression in liver, thyroid, colon, gastric and breast carcinomas, making Gal-3 an emerging cancer marker.