Resistance to vemurafenib in melanoma frequently results from reactivation of ERK pathway signaling by a variety of genetic mechanisms that include activating mutations of NRAS or KRAS, amplification of mutant BRAF, aberrant splicing of BRAF, and activating mutation of MAP2K1, which encodes the MEK1 protein [7, 8]. This evidence concerns the gene MAP2K1 and melanoma.