Recently, we have provided evidence that drugs inhibiting the MEK/ERK1/2 module can simultaneously induce the activation of one cellular response (migration) and the suppression of another (proliferation) in one and the same cell line (i.e., Cal-62 thyroid carcinoma cells), a phenomenon that we have designated as the yin-yang effect [25]. This evidence concerns the gene MAP2K7 and thyroid gland carcinoma.