Knockdown of AHR inhibits ESCC invasion and results in relative protein expression levels change. a Transwell assay indicated that after transfection, ESCC cell lines lost the capacity of invasion compared with high AHR expression cells. Magnification: 100×. b Western blot showed the down-regulation of relative protein expression regarding cell growth, apoptosis, migration and invasion. *, P < 0.05; **, P < 0.01; ***, P < 0.001; N.S, no significance