Aim: CD44 is a polymorphic family of cell surface proteoglycans and glycoproteins implicated in cell-to-cell and cell-to-matrix adhesion interactions and tumor metastasis. Its expression appears to be an indicator of invasive and metastatic behaviour in carcinomas. The purpose of our study is to investigate the immunohistochemical expression of CD44 protein in thyroid lesions and its association to other histopathological parameters.

Material and Methods: Samples from thyroid lesions were obtained from 40 patients treated in our Hospital. The material consisted of 5 cases of multinodular goiter, 7 cases of thyroiditis Hashimoto, 5 cases of follicular adenoma, 4 cases of Hurthle cell tumor, 15 cases of thyroid carcinoma (11 papillary carcinomas, and 4 myeloid tumors), and 4 cases of normal thyroid tissue. Immunostaining was performed using the Ventana ES automated immunostainer. A monoclonal antibody was used and avidin-biotin method was applied to paraffin-embedded samples. A membranous immunostaining pattern was considered positive.

Results: CD44 expression was detected in three adenomas (60%), mostly of follicular type, and in 8 carcinomas (72%). The CD44 immunostaining was especially apparent in papillary type of carcinomas, which showed high expression. In normal thyroid tissue, a reduced CD44 expression was observed.

Conclusions: The results of our study indicate that deregulated expression of CD44 contributes to the ability of thyroid carcinomas for invasion and metastasis and may constitute a prognostic factor for malignant biological behaviour.

Key words: CD44, immunohistochemistry, thyroid gland.

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