GPC3 overexpression has a role in carcinogenesis, particularly in hepatocellular carcinoma [ 9, 15- 22] but recently it was apparent that GPC3 expression is involved in different extra-hepatic malignant tumors including malignant melanoma [ 23], pulmonary squamous cell carcinoma [ 13], Merkel cell carcinoma [ 24], and chromophobe renal cell carcinoma [ 25]. The gene discussed is GPC3; the disease is Merkel cell skin cancer.