We characterized the mutational landscape of human skin cutaneous melanoma (SKCM) using data obtained from The Cancer Genome Atlas (TCGA) project.,We analyzed next-generation sequencing data of somatic copy number alterations and somatic mutations in 303 metastatic melanomas.,We were able to confirm preeminent drivers of melanoma as well as identify new melanoma genes.,The TCGA SKCM study confirmed a dominance of somatic BRAF mutations in 50% of patients.,The mutational burden of melanoma patients is an order of magnitude higher than of other TCGA cohorts.,A multi-step filter enriched somatic mutations while accounting for recurrence, conservation, and basal rate.,Thus, this filter can serve as a paradigm for analysis of genome-wide next-generation sequencing data of large cohorts with a high mutational burden.,Analysis of TCGA melanoma data using such a multi-step filter discovered novel and statistically significant potential melanoma driver genes.,In the context of the Pan-Cancer study we report a detailed analysis of the mutational landscape of BRAF and other drivers across cancer tissues.,Integrated analysis of somatic mutations, somatic copy number alterations, low pass copy numbers, and gene expression of the melanogenesis pathway shows coordination of proliferative events by Gs-protein and cyclin signaling at a systems level.
Melanoma is highly resistant to current modalities of therapy, with the extent of pigmentation playing an important role in therapeutic resistance.,Nuclear factor-κB (NF-κB) is constitutively activated in melanoma and can serve as a molecular target for cancer therapy and steroid/secosteroid action.,Cultured melanoma cells were used for mechanistic studies on NF-κB activity, utilising immunofluorescence, western blotting, EMSA, ELISA, gene reporter, and estimated DNA synthesis assays.,Formalin-fixed, paraffin-embedded specimens from melanoma patients were used for immunocytochemical analysis of NF-κB activity in situ.,Novel 20-hydroxyvitamin (20(OH)D3) and classical 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) secosteroids inhibited melanoma cell proliferation.,Active forms of vitamin D were found to inhibit NF-κB activity in nonpigmented cells, while having no effect on pigmented cells.,Treatment of nonpigmented cells with vitamin D3 derivatives inhibited NF-κB DNA binding and NF-κB-dependent reporter assays, as well as inhibited the nuclear translocation of the p65 NF-κB subunit and its accumulation in the cytoplasm.,Moreover, analysis of biopsies of melanoma patients showed that nonpigmented and slightly pigmented melanomas displayed higher nuclear NF-κB p65 expression than highly pigmented melanomas.,Classical 1,25(OH)2D3 and novel 20(OH)D3 hydroxyderivatives of vitamin D3 can target NF-κB and regulate melanoma progression in nonpigmented melanoma cells.,Melanin pigmentation is associated with the resistance of melanomas to 20(OH)D3 and 1,25(OH)2D3 treatment.