PTEN and melanoma: Three key molecular pathways have been found to be highly deregulated in melanoma: mitogen-activated protein kinase (MAPK), as a result of mutations in RAS, RAF, and KIT; PI3K/AKT, as a consequence of mutations in RAS, mutations or loss of PTEN (phosphatase and tensin homolog) and dysregulated expression of AKT, and p16INK4A due to mutations in CDKN2A, ARF, and p53. Various strategies of targeting melanoma have emerged based on the information gained from analyses of these pathways with varying success.