Sensitivity is lower in needle biopsies [23] and the specificity is also low, since Glypican 3 marks other hepatic or extrahepatic tumors, such as hepatoblastomas, ovarian clear cell carcinomas, testicular yolk sac tumors, choriocarcinomas, and specific subsets of melanomas and lung squamous cell carcinomas [24]. The gene discussed is GPC3; the disease is testicular yolk sac tumor.