BRAF and melanoma: There are many differences among the subtypes in terms of mutations burden: melanomas arisen on chronically sun-exposed skin harbor the highest numbers of mutations, especially NF1 and NRAS, and occasionally BRAF [50], while melanomas arisen on intermittently sun-exposed skin usually have an intermediate number of mutations, the commonest being BRAF V600E (50%) and NRAS (15–20%).