DDX3X and melanoma: The second group comprised of serine/threonine-protein phosphatase 6 catalytic subunit (PPP6C), DEAD-box helicase 3 X-linked (DDX3X), phosphatase and tension homology (PTEN), and ras-related C3 botulinum toxin substrate 1 (RAC1) genes, which showed mutations in 5 to 9% melanoma tissues.