STAT3 and lung cancer: Carnosol, luteolin and cirsiliol showed dose-dependent anti-proliferative activity against hepatoma HepG2 cells and lung cancer A549 cells and their anti-proliferative activity was enhanced by gefitinib, which is known to inhibit EGFR-dependent STAT3 activation but not IL-6-dependent STAT3 activation [23] (Fig. 3A and B).