Expression of Thyroid Transcription Factor-1 and Ki-67 in the Thyroid Neoplasms

ABSTRACT

PURPOSE: Thyroid transcription factor-1 (TTF-1) has been known to regulate the transcriptional activity of thyroid-specific genes. Ki-67 has been known as a marker for indicating tumor growth. This study was designed to campare the expressions of TTF-1 and Ki-67 on non- neoplastic and neoplastic thyroid tissues. METHODS: The surgically resected specimens of various histological types of thyroid tumor, from the files of the Dept. of surgery, Chung-Ang University Pil-Dong Hospital, between January 1998 and June 2002 were reviewed, and 55 cases selected for immunohistochemical studies. The materials consisted of tissues from 10 nodular hyperplasias, 28 papillary carcinomas, 15 follicular adenomas and 12 follicular carcinomas. All specimens were routinely processed, and paraffin blocks were available in all cases. Immunohistochemical stains for TTF-1 and Ki-67 were also performed. RESULTS: In all the cases, including the nodular hyperplasias, papillary carcinomas, follicular adenomas and follicular carcinomas, expressions of the TTF-1 were observed. The properties of the TTF-1 expression, including staining intensity, extent and index were not related to the tumor type. The expression of TTF-1 was inversely correlated with the tumor proliferation fraction, as assessed by the Ki-67 staining index. CONCLUSION: TTF-1 was expressed in almost all the benign lesions and well differentiated carcinomas, and correlated with the tumor proliferation fraction.