APE 1 promotes the metastatic potential of xenograft lung cancer cells in nude mice. One million HCC 827/ IR cells were inoculated subcutaneously into nude mice which were then treated with icotinib at 0 mg/kg, 70 mg/kg alone, and 70 mg/kg together with E3330 at 25 mg/kg (n = 6 mice or 12 xenografts/group). Xenograft growth was measured in two dimensions, and volume was recorded (tumor size (mm 3 ) = (maximum diameter ×minimum diameter 2 )/2) (A). After daily treatment for 12 d, the nude mice were sacrificed, and histologically intact xenografts were collected. The expression of APE 1, <t>E‐cadherin,</t> and vimentin in the xenograft extracts was detected by Western blot (B). EMT analyses of tissue slides were performed via IHC staining of E‐cadherin and vimentin (C). The mean values of the 12 xenografts of each group are shown as the mean ± SD , * Statistically significant difference when compared with the control group ( P