The immunohistochemical assay for glypican-3 (GPC3) aims to detect this cell membrane-bound glycoprotein via glycosylphosphatidylinositol. GPC3 is a highly specific marker for hepatocellular carcinoma (HCC), as it is expressed in the majority of HCC cases but not in normal liver or in most metastatic tumors to the liver or hepatocellular adenocarcinomas (HCAs).