SPP1 and posterior cortical atrophy: Characterization of OPN in prostate cell lines identified main molecular masses of 42, 52, and 70 kDa as well as the 32 kDa cleaved peptide in both benign and PCa cells, whereas the M0-differentiated THP-1 macrophages show a switch to unique OPN variants of 48 and 68 kDa.