BRAFV600E expression. Areas with increased mitotic activity (A, inset), percentage of cells stained for Ki-67 in mutant and wild-type cases (B), percentage of cells stained for pERK in mutant and wild-type cases (C), representative immunohistochemistry for pERK in a mutant (D, case 11) and wild-type case (E, case 26, ×10 lens), and percentage of cells strongly stained for p53 (F).