NRAS and melanoma: MeWo (BRAF wildtype, NRAS wildtype), SkMel28 (BRAF V600E mutant, NRAS wildtype), HT144 (BRAF V600E mutant, NRAS wildtype) and UACC62 (BRAF V600E mutant, NRAS wildtype) melanoma cell lines were screened for PTEN protein.