Differential (Ha-, K- and N-) ras p21 expression in benign and malignant human thyroid tumors: an immunohistochemical study.

An immunohistochemical study of 24 thyroid carcinomas, 10 thyroid adenomas and 10 normal thyroids was performed using monoclonal antibodies directed against each of the three members of ras p21s; Ha-, K- and N-ras p21. Normal thyroids showed a negative staining for all of the three ras p21s. The expressional levels of the three ras p21s were various in each benign and malignant thyroid tumor, but a higher expression of Ha- and N-ras p21 and a lower or negative expression of K-ras p21 was a common finding in thyroid tumors of all histologic categories. There were no correlations between the expressional levels of ras p21s and the histologic subtypes, tumor size or lymph node status in the thyroid carcinomas.