NRAS and melanoma: When MAF values of the primary melanoma were compared to the most frequent metastatic sites, it was found that in case of BRAF mutant tumors the increase in MAF was due to a significant increase in lung-, adrenal-, intestinal- and kidney metastases (Fig. 2a), whereas no significant alterations were detected in metastatic sites of NRAS mutant tumors (Fig. 2b).