TTF, 1 was expressed in the majority of benign and malignant thyroid diseases. The immnostaining of TTF, 1 was located in nuclear of cells, TTF, 1 was a sensitive marker for thyroid follicular cells.

Employing immunoperoxidase technique to determine the distribution of thyroglobulin and thyroxine in the thyroid made us possible to understand the functional state of follicular cell.

Sodium iodide symporter (NIS) mediates the accumulation of iodide in thyroid follicular cells, and becomes the molecular biology basis to diagnose and treat benign and malignant thyroid diseases.