Monomeric (but multidomain) albumin does not bind selenium ions unlike anintracellular monomeric Se-bound phospholipid hydroperoxide glutathione peroxidase (glutathione peroxidase 4, PHGPx, GPx4, EC 1.11.1.12), which plays an important role in cellular protection against the damaging effects of lipid hydroperoxides [99,100,101], and also unlike an extracellular tetrameric glutathione peroxidase 3 (GPx3, EC 1.11.1.9), a decreased activity of which is associated with enhanced risk of cancer diseases. Here, GPX4 is linked to cancer.