Fig 1: Western blot analysis showing the expression of EGFR and RAS/RAF/MEK/ERK pathway between sorafenib sensitive and resistant HCC cell lines after sorafenib treatment. Cell lines were serum starved overnight and then treated with increasing concentrations of sorafenib for an additional 2 hours. Constitutive basal expression and phosphorylation status of BRAF, CRAF, MEK, and ERK proteins were examined by Western blot analysis. GAPDH level was measured as a loading control. Twenty micrograms of proteins were separated on SDS-PAGE and Western blotting was performed using antibodies to EGFR, BRAF, CRAF, MEK, ERK, and Cyclin D.