<qa>  What is the synergistic interaction between erlotinib and capecita1.2.3 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. 