E-cadherin expression is more associated with histopathological type of thyroid cancer than with the metastatic potential of tumors.

The aim of this study was to evaluate the relationship between abnormal expression of E-cadherin (E-CAD) and the extracapsular extension of tumors, lymph node involvement and the presence of metastasis in various types of thyroid cancers. Histopathological specimens of 35 benign thyroid lesions and 122 malignant tumors (papillary, follicular, poorly differentiated and undifferentiated cancers) were analyzed. E-CAD immunostaining intensity, its subcellular localization, homogeneity within lesion, and the relation of staining intensity between tumor and surrounding thyroid parenchyma were evaluated. The obtained results show that the variants of differentiated cancers with a poorer prognosis (i.e. tall cell and follicular variants of papillary cancer and widely invasive follicular cancers) present reduced intensity of E-CAD expression, its abnormal localization or heterogeneity of staining more frequently than classical papillary cancers and minimally invasive follicular cancers. However, the assessment of E-CAD expression does not allow the prediction of extrathyroidal growth of thyroid cancers.