Galectin-1, a polypeptidic factor that can have major effects on cell growth and apoptosis, is an important regulator of leukocyte function and tumor angiogenesis. Galectin-1 belongs to a family of 15 structurally related β-galactoside binding proteins that are able to control a variety of cellular events, including cell cycle regulation, adhesion, proliferation, and apoptosis. Human Galectin-1 shares 88% aa sequence identity with mouse, equine and ovine, 90% with rat, and 87% with bovine and porcine Galectin-1. Recombinant human galectin-1 to three porphyrin compounds: Zn-porphyrin (ZnTPPS). Mn-porphyrin and Au-porphyrin. These compounds are widely applied in the photodynamic therapy of cancer. Galectin-1 can also modulate cell-cell and cell-matrix interactions.