[Immunohistochemical study of epidermal growth factor receptor and estrogen receptor in human thyroid tumors]

Expressions of epidermal growth factor receptor (EGFR) and estrogen receptor (ER) in human thyroid tumors were examined immunohistochemically in frozen sections. Forty-eight fresh surgical specimens of thyroid tissues, 19 carcinomas, 12 adenomas, 7 adenomatous goiters and 10 normal thyroid tissues were studied. All cases, including normal thyroid tissues, expressed the EGFR immunoreaction in the cytoplasm. Incidences of stronger than (+) staining intensity of EGFR were 84% (16/19) in carcinoma, 67% (8/12) in adenoma, 57% (4/7) in adenomatous goiter and 30% (3/10) in normal thyroid tissue. This result suggests that the staining intensity of EGFR expression is associated with malignant potential. The frequency of ER positive cases was 11% (2/19) in carcinoma, 17% (2/12) in adenoma and 0% in both adenomatous goiter and normal thyroid tissue. No relationship between EGFR and ER expression was recognized. However, a case of papillary carcinoma with strong ER immunoreactive intensity expressed weak EGFR intensity, suggesting an inverse relation in immunoreaction between EGFR and ER in papillary carcinoma.