Immunohistochemical study of glypican 3 in thyroid cancer

In 123 patients with thyroid cancer, expression of glypican 3 (GPC3) was immunohistochemically investigated in tissue samples and the biological significance of GPC3 in thyroid cancer was examined. GPC3 was scarcely expressed in the normal thyroid gland, but was dramatically enhanced in certain types of cancers: 100% in follicular carcinoma (20/20 cases) and 70% in papillary carcinoma (48/69 cases). Expression of GPC3 in follicular carcinoma was significantly higher than that of follicular adenoma (p < 0.0019). In contrast, GPC 3 was not expressed in 17 cases of anaplastic carcinoma. A high expression of GPC3 mRNA was confirmed in cancer lesions, which were strongly positive for immunohistochemical staining. In 69 cases of papillary carcinoma, GPC3 was expressed at an early stage, suggesting that GPC3 expression in thyroid cancer is an early event in developing papillary carcinoma. Further studies are required to determine biological functions and molecular mechanisms underlying the upregulation of GPC3 in thyroid cancer.