GPC3 and hepatocellular carcinoma: Glypican-3, a heparin sulphate proteoglycan expressed at high levels in HCC, has shown high specificity with suboptimal sensitivity in the diagnosis of HCC when used in isolation as it is well known to be immunoreactive in a wide variety of tumors, including pulmonary squamous cell carcinoma,[15] germ cell tumors,[16] and a subset of gastric adenocarcinomas[17].