NAMPT and metastatic melanoma: NAMPT overexpression increased MAPK signaling activation, colony-formation capacity, mesenchymal phenotype, and the drug-effluxing stem cell-like side population (SP) of cells and promoted tumorigenicity in vivo in a highly aggressive type of skin cancer, metastatic melanoma harboring serine-threonine protein kinase B-RAF (BRAF) mutation [62].