Galectin-3 is an isotypic cell adhesion lectin, which is a chimeric structure composed of a β-galactosidase bond binding protein (Galectin-3 domain) and a laminin. galectin-3 on the cell surface is mainly related to the adhesion between the same kind of cells. It can down-regulate the expression of some cecal and breast cancer related proteins and promote the metastasis of these tumors. Galectin-3 can also be used in combination with CK19 for the differential diagnosis of thyroid follicular adenoma, follicular carcinoma and papillary carcinoma.