In vitro experiments provide evidences that the inhibitory action of berberine on NPC cells could be mediated by directly inhibiting the constitutive activation of STAT3 or by inhibiting the STAT3 activation induced by exogenous pro-inflammatory cytokines such as IL-6 (Figures 3, 4, 5, 6). This evidence concerns the gene STAT3 and nasopharyngeal carcinoma.