Galectin-3 Immunoreactivity in Papillary Thyroid Carcinoma

Thyroid cancer is a common head and neck malignancy. It is the most common endocrine tumor in the body accounting for 1% of all cancers worldwide. The incidence of thyroid cancer varies worldwide. Most countries have reported an upward trend in its incidence.

Thyroid cancer encompass the most common well-differentiated papillary carcinoma (80% of all thyroid cancers) and follicular carcinoma (15%), as well as poorly differentiated carcinoma (< 1%) and anaplastic carcinoma (< 2%).

Papillary thyroid carcinomas (PTCs) are the most commonly encountered thyroid malignancies. The diagnosis of PTC is based on the special nuclear features such as overlapping of nuclei, intranuclear inclusions, optical clearing, anisonucleosis and nuclear grooves. However, it is often difficult to differentiate PTC from benign papillary thyroid hyperplasia . As differentiation between benign or malignant thyroid lesions has clinical, therapeutic, and prognostic significance, it is necessary to make accurate diagnosis by using biomarkers.

Recently, a large number of immunohistochemical (IHC) markers have been studied to assist in differentiating non-neoplastic lesions from malignant thyroid lesions. CK19, galectin-3, TG, Ki67, BRAF, calcitonin, HBME-1, TTF-1, and RET are some of the examples of these IHC markers.

Galectin-3 is a 31-kDa β-galactoside binding lectin. It has been shown to be expressed by several types of non-neoplastic and neoplastic cells, and it is involved in cell-cell adhesion and in cell-matrix interactions.