CLINICAL-SIGNIFICANCE OF E-CADHERIN AS A PROGNOSTIC MARKER IN THYROIDCARCINOMAS

The aim of this study was to evaluate the expression of E-cadherin as a potential marker for the prognosis of thyroid carcinomas. In normal thyroid (n = 8), the expression of E-cadherin messenger ribonucleic ac id levels was uniformly high and seemed to be restricted to thyrocytes . Steady-state messenger ribonucleic acid levels and immunostaining we re both completely lost in undifferentiated thyroid carcinomas (n = 7) and were variably reduced in differentiated thyroid carcinomas (n = 4 4). In a follow-up study during a mean of 4.5 +/- 1.4 yr, E-cadherin m essenger ribonucleic acid and immunohistochemical expression were comp ared with the initial clinicopathological parameters and with locoregi onal recurrence and the development of nodal or distant metastases in differentiated thyroid carcinomas. Immunohistochemical expression of E -cadherin was greatly reduced with the progression to primary tumor st age 4 (pT4) tumors. In parallel, patients with pT4 tumors had a higher rate of locoregional tumor recurrence and distant metastasis than did the group of patients with pT1-3 tumors. In 5 of 29 patients with pT4 tumors, positive E-cadherin staining of more than 30% of the cells wa s detected. None of these patients showed signs of a regional recurren ce or distant metastases during an observation period of 4.3 +/- 1.1 y r. In 13 patients with E-cadherin-positive tumors, none developed new = distant metastases which was in contrast to 7 of the group of 31 pat ients with less than 30% E-cadherin-positive cells. Thus, E-cadherin e xpression seems to be associated with the dedifferentiation, progressi on, and metastatic spread of thyroid carcinomas and map be a useful ma rker for the prognosis of these tumors.