 1.2.3 The synergistic interaction of erlotinib and capecitabine in NSCLC. Giovannetti et al reported that erlotinib significantly reduced TS expression and activity, possibly via E2F-1 reduction, as detected by RT-PCR and western blot, and the combination decreased TS in situ activity in NSCLC cells. Furthermore, Van SS. et al found TS inhibitor 5-FU increases EGFR phosphorylation which potentially favors EGFR-TKIs activity.Thus, erlotinib and capecitabine may have a strong synergism in NSCLC. 