BRAF and melanoma: Instead, research about class III mutant that have impaired kinase activity or are kinase-dead and linked with high RAS levels suggest Class III BRAF mutants may be treated with MEK inhibitors which co-existing with mutations in RAS and NF1 in melanomas, but in epithelial tumors, the great majority of class III mutations are not associated with RAS/NF1 alterations and may be treated with receptor tyrosine kinase (RTK) inhibitors that block the RAS pathway (20).