DKK1 and melanoma: These genes encode the following groups of proteins: (a) regulators of proliferation, e.g., vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), c-JUN, FOS-related antigen 1 (FRA1); (b) regulators of the canonical WNT pathway e.g., WNT1-inducible-signaling pathway protein 1 (WISP1), AXIN, Dickkopf-1 (DKK1), TCF, LEF1; (c) matrix metalloproteinases and some components of extracellular matrix; (d) cadherins; (e) lineage-specific proteins such as microphthalmia-associated transcription factor (MITF), which modulates several functions in melanocytes and melanoma [42].