PLX4032 modulation of the MAPK pathway and melanoma cell line viability. Melanoma cell lines treated with 1 μM PLX4032 for 20 hours were stained with pErk antibody and analyzed by flow cytometry. a) Representative flow cytometry histogram showing the fluorescence intensity of pErk in cells treated with vehicle control or PLX4032. b) Comparison of percentage change in pErk for a panel of 10 melanoma cell lines with different NRAS/BRAF mutational status. c) In vitro cell viability upon culture with increasing concentrations of PLX4032 (from 0.001-10 μM) for 120 hours. Cell viability was determined using an MTS-based assay.