<p><i>BRAF</i> functional domains and comparison between the 1-2-3 and A-B-C <i>BRAF</i> classification systems. The 1-2-3 <i>BRAF</i> mutation classification is based on <i>in vitro</i> assays of Ras pathway activity. However, as it has not been validated by the analysis of native mutations in isogenic cells, we explored, in parallel, a simpler classification based on the mutation location in functional domains: A, codon 600; B, other active site mutations flanking codon 600 (581–601); and C, ATP-binding site mutations (464–469). RBD, Ras-binding domain. (Created with <a href="http://BioRender.com" target="_blank">BioRender.com</a>.)</p>