[Ghrelin expression in the tissues of different thyroid diseases].

OBJECTIVE

To investigate whether ghrelin, a novel endogenous ligand of growth hormone secretagogue receptor (GHS-R), was expressed in the thyroid tissues of different thyroid diseases, and its implication.

METHODS

The paraffin-embedded specimens of thyroid tissues from 2000 to 2004 were obtained from 57 patients with different thyroid diseases, including 5 subacute thyroiditis, 8 Hashimoto's thyroiditis, 7 hyperthyroidism (Graves disease), 8 nodular goiter, 5 thyroid adenoma, 3 thyroid lymphoma, 8 papillary carcinoma, 3 follicular carcinoma, 5 medullary carcinoma and 5 undifferentiated carcinoma cases. The specimens of normal peri-adenoma thyroid tissues served as controls. Immunohistochemical staining was used to detect ghrelin expression.

RESULTS

(1) ghrelin expression was undetectable in the thyroid tissues of normal control, subacute thyroiditis, Hashimoto's thyroiditis and Graves disease. (2) ghrelin expression was also undetected in the tissues of nodular goiter, thyroid adenoma and thyroid lymphoma. (3) ghrelin-positive staining was found in the tumor cells of different types of thyroid carcinoma. Five cases were positive within 8 cases in papillary carcinoma, 2 cases were positive within 3 cases in follicular carcinoma, 3 cases were positive within 5 cases in medullary carcinoma, 3 cases were positive within 5 cases in undifferentiated carcinoma.

CONCLUSION

Ghrelin is expressed in malignant epithelial thyroid neoplasms, but not in autoimmune or inflammatory thyroid diseases and benign nodular thyroid diseases. The results indicate that ghrelin expression may play an important role in the occurrence and development of thyroid carcinoma.