The Wnt family includes several secreted glycoproteins that play important roles in animal development. There are 19 Wnt genes in the human genome that encode functionally distinct Wnt proteins. Wnt members bind to the Frizzled family of seven-pass transmembrane proteins and activate several signaling pathways. The canonical Wnt/β-catenin pathway also requires a coreceptor from the low-density lipoprotein receptor family. Aberrant activation of Wnt signaling pathways is involved in several types of cancers. Wnt-5a has been shown to signal through the canonical Wnt pathways as well as through non-canonical pathways and is up-regulated in various types of human cancers. In melanoma, Wnt5a is thought to directly affect cell motility and metastasis.