In these cases the differential diagnosis requires the use of other markers such as S-100 and other tumour specific proteins according to the presumed origin (e.g PSA for prostatic carcinoma, glypican 3 for hepatocellular carcinoma, PAX8 for renal carcinoma and CDX-2 for colorectal carcinoma). The gene discussed is GPC3; the disease is renal carcinoma.