In addition, given that BRAF-mutant thyroid cancer cells usually showed intrinsic resistance to BRAF kinase inhibitors due to the feedback activation of epidermal growth factor receptor 3 (EGFR3/HER3) [12], thus, we only tested the response of these cells to MEK inhibitor GSK1120212 in the present study. This evidence concerns the gene MAP2K7 and thyroid cancer.