Pathogenic BRAF mutations, which lead to the constitutive activation of the MPAK signaling cascade, are present in approximately 4% of all cancers, with the substitution of valine for glutamate at codon 600—BRAF V600E—accounting for at least 56% of all BRAF mutations and 70% of all PTCs [35,50,51]. The gene discussed is BRAF; the disease is cancer.