B, The Fa-CI plot of drug combinations (candidate drug plus BI2536) in KRAS-mutant (BEAS-2B-KRAS) and wild-type (BEAS-2B) cells. The data are mean values of two independent experiments (n=2) where all drugs are used at their IC50 determined in BEAS-2B-KRAS cells. Note that combination treatment with AZD4547 and BI2536 exhibit the leading therapeutic efficacy and safety profile, manifested by the greatest synergy (CI=0.25) in BEAS-2B-KRAS while the two drugs are antagonistic in BEAS-2B cells (CI>1). 