ABCB1 and hepatocellular carcinoma: Slight inhibitory effect on cell proliferation at higher doses, significant inhibition of cell proliferation and hepatoma growth by the administration of DOX with EGCG at lower doses in vitro in a xenograft mouse model, increasing DOX and Rh-123 accumulations, decrease of P-gp in cells concurrently treated by DOX and EGCG, expression of MDR1 mRNA in BEL-7404/DOX cells treated by DOX and EGCG reduced