Mutations in BRAF lead to constitutive activation of downstream signaling of the RAS-RAF-MEK-ERK (mitogen-activated protein kinase) signal transduction pathway in 40-60% of cutaneous melanoma with substitution of glutamic acid for valine at codon 600 in 90% of the BRAF-mutated melanoma [20,21]. The gene discussed is BRAF; the disease is melanoma.