CD33 and neoplasm: Considering that Gal-9 is a secreting protein, here we further assess the repercussions of Gal-9 expression in malignant cells on the regulation of bystander CD33+ cells belonging to the human myeloid lineage and the effect of extracellular Gal-9 on CD33+ cell function and differentiation using RhGal-9 protein or tumor-derived exosomes (T-EXO) with substantial Gal-9 abundance.