Immunostaining with P-gp. The parental Tca8113 cells were induced with increasing concentrations of CBP or PYM for six months. Cells were then stained by immunohistochemistry and visualized under magnification of x10 (stain, Mayer's hematoxylin). (A) Parental, (B) CBP-induced and (C) PYM-induced Tca8113 cells. The figures are representative of three independent experiments. P-gp, P-glycoprotein; CBP, carboplatin; PYM, pingyangmycin.