Galectin-3 is a member of the lectin family and contains a carbohydrate-recognition-binding domain that binds to β-galactoside. Due to its ability to bind to β-galactoside, galectin-3 plays an important role in cell-cell adhesion, cell-matrix interactions, macrophage activation, angiogenesis, metastasis, apoptosis. Given galectin-3's broad biological functionality, it has been demonstrated to be involved in a number of diseases including cancer, fibrosis, heart disease, and stroke. Overexpression of galectin-3 is commonly seen in cancerous conditions and can affect cancer cell growth and differentiation, chemoattraction, apoptosis, and metastasis. Because of this, galectin-3 is increasingly being used as a diagnostic marker for different cancers.