LGALS9 and acute myeloid leukemia: Galectin-9 (Gal-9), a β-galactoside binding lectin, was declared as its natural ligand in AML, as it binds to the IgV domain of TIM-3 and induces the phosphorylation of two tyrosine residues in the cytoplasmic tail of TIM-3 (30, 31).