LGALS1 and leukemia: Indeed, in our studies, it was difficult to assign a specific contribution of Galectin-1 versus Galectin-3 because there are two potential sources of both extracellular/cell-surface-bound Galectin-1 as well as Galectin-3 protein: (1) that which is secreted by bone marrow stromal cells and can bind to the surface of the leukemia cells, and (2) that which is produced endogenously by the leukemia cells, of which an unknown fraction is transported to the cell surface and/or secreted.