Anti-PSG9 antibodies are used in the immunodetection of the protein pregnancy specific beta-1-glycoprotein 9. In humans, the canonical protein has a reported length of 426 amino acid residues and a mass of 48.3 kDa. It has been described to be a secreted protein. Up to 2 different isoforms have been reported for this protein. It is notably expressed in the placenta and testis. A member of the CEA protein family, PSG9 is known to bind to the small latent transforming growth factor-beta complex, consisting of the N-terminal TGFB1 latency-associated peptide (LAP) and the mature form of TGFB1, thereby leading to the activation of TGFB1. Post-translational modifications have been described, including glycosylation. Synonyms for this target antigen include PS34 and PSBG-11. PSG9 gene orthologs have been reported in the mouse and chimpanzee species. Some PSG9 antibodies may have been used in research and have associated citations. Western Blot is a widely used application for these antibodies. ELISA and Immunohistochemistry are also common applications.