In support for a contribution of intracellular Galectins, we here found that endogenous Galectins (either Galectin-1, Galectin-3, or both) also regulate motility because Lgals1 × Lgals3 -/- dKO BCP-ALL cells had reduced migration to stromal fibroblasts. The gene discussed is LGALS3; the disease is acute lymphoblastic leukemia.