[Expression of TTF-1 in thyroid tumors originating from follicular epithelium and its correlation with expression of RET, galectin-3 and mucin-1 genes].
OBJECTIVE
To explore the expression of thyroid transcription factor-1 (TTF-1) in thyroid tumors and in different parts of follicular epithelium and the correlation of expression of TTF-1 with the expression of RET, galectin-3 (Gal-3) and mucin-1 (MUC1) genes.


METHODS
One hundred thirty-three samples of resected thyroid tumors were examined by streptavidin/peroxidase (S-P) immunohistochemical technique to detect the expression of TTF-1 and RET, Gal-3, and MUC1 genes.


RESULTS
(1) TTF-1 was expressed in the nuclei and cytoplasm of different kinds of tumor cells and normal cells around the tumors. There was no significant difference between the expression of TTF-1 in nuclei of malignant thyroid tumor cells and that in nuclei of benign thyroid tumor cells (P > 0.05). The positive expression rate of TTF-1 was 27.40% in cytoplasm of benign tumor and was 66.10% in cytoplasm of malignant tumor was 66.10% (P < 0.05). (2) The expression rate of RET gene was 38.9% in thyroid adenoma, 88.4% in papillary carcinoma, and 87.5% in follicular carcinoma. The difference of expression rate of RET gene between adenoma and both of papillary and follicular carcinomas was statistically significant (P < 0.05). (3) The expression rate of MUC1 was 23.3% in benign tumor and 50.9% in malignant tumor. The expression rate of MUC1 was lower in benign thyroid diseases (nodular goiter and adenoma) than in thyroid papillary carcinoma and follicular carcinoma (P < 0.05). (4) The expression rate of Gal-3 gene was 38.4% in benign tumor and 88.1% in malignant tumor. (5) The expression rates of Gal-3 and MUC1 in benign lesions (nodular goiter and adenoma) were lower than those in thyroid papillary and follicular carcinomas (P < 0.05). The expression of Gal-3 and that of MUC1 in thyroid carcinomas were fundamentally parallel. However, the sensitivity of Gal-3 was higher than that of MUC1. In part of adenomas Gal-1 and MUC1 were positive locally simultaneously. The expression of TTF-1 in cytoplasm was associated with that of Gal-3 and MUC1.


CONCLUSIONS
The expression of TTF-1 in nucleus is a phenomenon common to both normal and pathological thyroid follicles. Combined tests of RET, Gal-3 and MUC1 may act as the diagnostic markers to distinguish benign follicular tumor from malignant ones. Expression of TTF-1 in cytoplasm is probably a characteristic of malignant phenotypes of thyroid tumors.
Chen
Yun
Y
Department of Pathology, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
Zhu
Minghua
M
Zhou
Xiaojun
X
Lin
Wanhe
W
Ni
Canrong
C
Li
Fangmei
F
Zhang
Shunmin
S
Gong
Zhijin
Z
D000818:Animals; D037502:Galectin 3 / Q000032:analysis* / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D018396:Mucin-1 / Q000032:analysis* / Q000235:genetics; D009687:Nuclear Proteins / Q000032:analysis*; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000235:genetics; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis*
D037502:Galectin 3; D018396:Mucin-1; C000614412:NKX2-1 protein, human; C000614414:Nkx2-1 protein, mouse; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C494999:Ret protein, mouse