EXPRESSION OF THE ESTROGEN-RECEPTOR IN HUMAN THYROID NEOPLASMS

The expression and quantitation of the estrogen receptor (ER) in human thyroid tumors were examined by biochemical, immunohistochemical, and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. For this study, neoplasms, adenomatous goiters and adjacent normal thy roid tissues were obtained from 35 patients which included 10 cases of papillary carcinomas, 17 cases of adenomas and 8 cases of adenomatous goiters. Regardless of the histopathological subtype, ER was detected in 19% (5/27) of the neoplastic tissues with the mean value of ER con tent of 5.0 +/- 1.3 fmol/mg protein and the mean K-d value of 0.38 +/- 0.28 nM. ER was also detected, but at a lower concentration (2.8 +/- 1.6 fmol/mg protein), in the surrounding normal tissues. There was no significant difference between the neoplasms and adenomatous goiters w ith respect to the incidence of ER positivity and ER content: Furtherm ore, ER-positive specimens, as determined by both biochemical and immu nohistochemical techniques, also showed the expression of ER mRNA dete cted by RT-PCR method. These results demonstrate that both ER mRNA as well as ER protein are expressed in thyroid neoplasms. This suggests t he possibility that estrogen may affect the tumorigenesis or the progr ession of some thyroid neoplasms.