Galectins comprise a family of soluble β-galactoside binding proteins, which regulate key biological processes including cell growth, differentiation, apoptosis, and immune responses.
Sixteen galectin genes have been identified in animal kingdoms, 12 of which are expressed in humans. Galectins are usually classified into three groups based on their structure: (i) prototypical galectins (galectin-1 (Gal1), Gal2, Gal5, Gal7, Gal10, Gal11, Gal 13, Gal14, and Gal15), characterized by a single CRD, which can act as monomers or form homodimers; (ii) the chimeric galectin Gal3 (the only member of this class), with a single CRD and a large amino-terminal domain that facilitates the formation of oligomers; (iii) the tandem repeat galectins, with two CRDs that are linked through a small peptide domain; this group includes Gal4, Gal6, Gal8, Gal9, and Gal12. Recently, Galectins have been implicated as major therapeutic determinants that confer sensitivity or resistance to a wide range of anticancer modalities including chemotherapy, radiotherapy, targeted therapies, antiangiogenic therapies, and immunotherapies.