Galectin-9 is a cytoplasmic protein that contains two galectin domains. Galectin-9 is an S-type lectin that is over-expressed in Hodgkin's disease tissue. Galectin-9 binds galactosides and has high affinity for the Forssman pentasaccharide. Galectin-9 plays a role in thymocyte-epithelial interactions relevant to the biology of the thymus and Inhibits cell proliferation. Galectin-9 is a ligand for HAVCR2/TIM3 and induces T-helper type 1 lymphocyte (Th1) death. In addition, Galectin-9 suppresses tumor cell metastasis by interfering with the associations CD44, VCAM-1, Integrin α4β1.