PTEN and melanoma: In addition, since inhibition of the AKT pathway is regarded as a reasonable therapeutic option in melanoma [24], [25], two melanoma cell lines carrying known PI3K/AKT pathway activating mutations served as positive controls; Skmel-28 was described to have a PTEN mutation [26] while sequencing of the NRAS gene in BLM cells revealed a Q61R mutation (data not shown).