Although the same trametinib concentration induced a reduction of MEK1/2 phosphorylation in the melanoma cells and effectively inhibited ERK1/2 (Additional file 12: Fig. S12A), a reduction of ERK1/2 phosphorylation in HDF was mainly effective at earlier time-points (4 h), but partially compensated afterwards through MEK1/2 hyperphosphorylation (Additional file 12: Fig. S12B). Here, MAP2K1 is linked to melanoma.