GPC3 is a 65kD, glycosylphosphatidylinositol (GPI) anchored 580 amino acid heparan sulphate proteoglycan [57,58], found on the placenta, where it plays a role in morphogenesis (via activation of the Wnt pathway), and in several solid tumours, including 72% of cases of HCC, where it portends to poor prognosis [59,60]. The gene discussed is GPC3; the disease is hepatocellular carcinoma.