Aim: Thyroid cancer represents the first endocrine malignant neoplasm, accounting for 1% of human malignancy. The majority of which are well-differentiated cancer representing up to 90% of thyroid cancer and pursuing a favorable clinical course. The groups of poorly differentiated thyroid cancer (PDC) and anaplastic thyroid cancer (ATC) have a poor outcome and need a strict clinical surveillance.
Materials and methods: Thirty-four cases including 23 PDC/insular cancer and 9 ATC were examined for the expression of an immunohistochemical panel made up by HBME-1, galectin-3, and β-catenin and correlated either with histologic prognostic parameters or the overall surveillance.
Results: HBME-1 and galectin-3 were expressed in 100% of the PDC/insular cases and in none of the ATC cases. The data for β-catenin pointed out an 80% expression (12/15) in the PDCs and only a focal and nonspecific positivity in the ATCs. A β-catenin-positive expression was found in all patients with a worse outcome/death and in the presence of vascular invasion and metastatic disease. All 3 PDC patients with β-catenin negativity are alive, whereas only 41% (5/12) are alive in the β-catenin-positive group.
Conclusions: Our data set up the idea that PDC represents an intermediate step in the biological process of dedifferentiation of thyroid tumors toward ATC. This shift is underlined by the β-catenin expression, which seems to be related to a worse prognostic behavior. HBME-1 and galectin-3 show a similar pattern in PDC compared with well-differentiated carcinoma, whereas they are not expressed, as well as β-catenin, in anaplastic carcinomas.