Endocrine Abstracts

Cadherins are proteins important for regulation of cell to cell adhesion. It has been postulated that the loss of cadherins may be an essential step in progression of cancer cell dedifferation, leading to increased metastatic potential. In the present study, the immunoexpression of E-cadherin was examined in various types of thyroid neoplasms and compared with that expression in normal thyroid tissue. The histopathological slides from 138 thyroid carcinomas (90 papillary, 8 follicular, 15 oxyphilic cell type, 14 poorly differentiated, and 11 undifferentiated), 16 follicular adenomas and 26 normal thyroids were immunostained with the use of anti E-cadherin antibody. The intensity of staining was assessed semiquantitatively by evaluation of 1000 cells in each lesion. The results were expressed in an ordinal scale from 0 to 4 (0 – staining present in <5% of cell, 1 – 6–30% of cells, 2 – 31–60% of cells, 3 – 61–90% of cells, and 4 – more than 90% of cells). Statistical significance was tested with Mann-Whitney U test. The lowest mean expression of E-cadherin was found in undifferentiated carcinomas (1.63) and the second lowest (2.07) – in poorly differentiated carcinoma. All other examined lesions showed significantly higher expression of E-cadherin (the highest expression was observed in follicular adenomas – 3.25 – P<0.005). There was no significant difference between undifferentiated and poorly differentiated carcinomas. Interestingly, there was a significant difference in immunoexpression of E-cadherin between follicular adenoma and papillary carcinoma (2.47, P<0.05) as well as normal thyroid tissue (2.69, P<0.05). The correlation between TNM classification and the level of E-cadherin immunoexpression was also examined. In the group of poorly or undifferentiated carcinomas there was a very weak negative correlation between the lymph nodes involvement and the level of E-cadherin immunostaining (Spearman coefficient=−0.25). No such correlation was observed in the groups of differentiated carcinomas. There was no correlation between the presence of metastases and the E-cadherin expression in none of the examined groups of cancers.

Conclusions: The loss of E-cadherin expression can be observed in poorly differentiated and undifferentiated carcinomas. However, it seems that prognostic value of E-cadherin immunoexpression is rather weak.