MAPK3 and melanoma: Western blot analysis was performed using phospho-ERK1/2, total ERK1/2 and β-actin antibodies, and results are shown in Figure 2A.In the MEK162 resistant melanoma cultures (YUVON and YUKSI), the baseline level of phospho-ERK1/2 and the ratio of phospho-ERK1/2 to total ERK1/2 was lower compared to sensitive cultures (YUROB, YUMAC, YUDOSO, YUKIM).