Anti-GPC3 antibodies are used in the immunodetection of the protein glypican 3. In humans, the canonical protein has a reported length of 580 amino acid residues and a mass of 65.6 kDa. Its subcellular localization is in the cell membrane. Up to 3 different isoforms have been reported for this protein. It is notably expressed in the placenta. A member of the Glypican protein family, GPC3 is known to be involved with the morphogenesis of anatomical structure and the Wnt signaling pathway. Post-translational modifications have been described, including O-glycosylation and protein cleavage. The GPC3 gene has been associated with the disease, Simpson-Golabi-Behmel syndrome. Synonyms for this target antigen include GTR2-2, MXR7, OCI-5, SDYS, SGB, SGBS, SGBS1, and DGSX. GPC3 gene orthologs have been reported in the mouse, rat, bovine, frog, chimpanzee and chicken species.