Background and purpose: Papillary thyroid cancer (PTC) is one of the most common carcinomas in humans. Galectin-3 is a multifunctional protein which regulates different process of tumorigenesis. Galectin-3 is widely distributed in various cancer tissues and the sera of cancer patients. The aim of this study was to explore the role of Galectin-3 in promoting PTC cells migration. Methods: Immunohistochemical analyses were performed on 40 PTC tissues and scores were calculated. PTC B-cpap cells were harvested after serum-free culture

and the extracellular and intracellular levels of Galectin-3 were measured. CCK-8 assay and wound healing assay were conducted after inhibition of Galectin-3 with two different methods. The transformation of cell morphology after inhibition of intracellular Galectin-3 was analyzed using immunofluorescence and confocal laser scanning. Results: Compared with those PTC patients without cervical lymph node metastasis

immunohistochemical scores of Galectin-3 were significantly higher in those with cervical lymph node metastases (P0.05). The inhibition of extracellular and intracellular Galectin-3 attenuated the migration ability of cancer cells

but had different impact on cell proliferation. Transformation of cell morphology was also observed after inhibition of intracellular Galectin-3. Conclusion: Galectin-3 expression in tumor tissues was related to PTC metastasis. Inhibition of extracellular and intracellular galectin-3 could significantly decrease PTC cell migration.