GALECTIN-3 IS A PRESURGICAL MARKER OF HUMAN THYROID-CARCINOMA

Galectin-3 is a carbohydrate-binding protein endon ed with an affinity for beta-galactosides. It has been shown to play an important role in cell-cell and cell-matrix interactions and in pre-mRNA splicing. Furt hermore, it is involved in the control of cell growth, neoplastic tran sformation, and metastasis. Interestingly, high levels of galectin-3 e xpression have been recently described in malignant thyroid neoplasias , but not in adenomas or in normal thyroid tissue. We investigated gal ectin-3 expression in human presurgical specimens obtained by fine-nee dle aspiration biopsy. We analyzed galectin-3 expression by immunopero xidase staining in both paraffin-embedded cytological thyroid sediment s (cell blocks) obtained by Fine-needle aspiration biopsy and their hi stological counterparts. A total of 64 samples were examined: 17 folli cular carcinomas; 18 papillary carcinomas; and 29 follicular adenomas. All cell blocks and histological samples of papillary carcinomas expr essed high levels of galectin-3 at either the cytoplasmic or nuclear l evel. Among follicular carcinomas, all histological samples expressed galectin-3, whereas 1 1 of 17 corresponding cell blocks were positive in the cytoplasm. No evidence of cytoplasmic galectin-3 expression was observed in 26 of 29 follicular adenomas. Hence, cytoplasmic galectin -3 staining seems to be a reliable, easy, and cheap marker for presurg ical diagnosis of follicular carcinomas and an even more suitable one for papillary carcinomas.