Dose-dependent change in protein levels were measured by western blot (data shown in Figures S2 and S3) and are marked with (+) for increase, (-) for decrease, (N.C) for no change, and (~) for not detected. The cell lines have various sensitivities for gefitinib: A431, IC50 = 40 - 80 nM; HCC827, 100 nM; H1650, 1 μM; H23, 8 μM; and H1975, 12 μM. Protein level changes of the panel of proteins after treatment with selective inhibitors of MAPK (PD 98059), AKT (LY294002), erlotinib (on-axis control), and paclitaxel (off-axis control) are shown.