Effects of miR-21 inhibition on the migration and invasion of HepG2 liver cancer cells. (A) Comparison of the migration distance/migration rate of HepG2 cells treated with miR-21 inhibitor or miR-21 inhibitor NC. (B) Comparison of the number of HepG2 cells treated with the (a) miR 21 inhibitor or (b) miR-21 inhibitor NC that crossed the polycarbonate membrane of the transwell invasion chamber (magnification, ×200). *P<0.05, **P<0.0001, compared with the NC-transfected cells. Data are presented as the mean ± standard deviation. miR-21, microRNA-21; NC, negative control.