MT-ND6 and melanoma: Missense and nonsense mutations in the mitochondrial gene ND6, which normally encodes a subunit of NADH dehydrogenase (ubiquinone), promote migration and invasion of A549 lung adenocarcinoma cells in vitro, probably via the increased generation of reactive oxygen species.187 Activating mutations in the GRM3 gene, which encodes a G-protein-coupled receptor, occur in melanoma and stimulate the migration of A375 melanoma cells in vitro, probably through phosphorylation of MEK.188