Kisspeptin is a G-protein coupled receptor ligand for GPR54. Kiss1 was originally identified as a human metastasis suppressor gene that has the ability to suppress melanoma and breast cancer metastasis. It is recently become clear that kisspeptin-GPR54 signaling has an important role in initiating GnRH secretion at puberty, the extent of which is an area of ongoing research.Kisspeptin is a metastasis suppressor of melanomas and breast cancers without affecting tumorigenicity. The encoded protein may function to inhibit chemotaxis and invasion, attenuating metastasis in malignant melanomas. Studies suggest a putative role in the regulation of events downstream of cell-matrix adhesion, perhaps involving cytoskeletal reorganization. A polymorphism in the terminal exon of this mRNA results in two protein isoforms.