ABCB1 and hepatocellular carcinoma: As for doxorubicin, another anthracycline, EGCG can enhance its antitumor ability on hepatoma cells, and re-sensitize hepatoma cells resistant to it through reversing the multiple resistance mechanisms, such as suppressing multidrug resistance 1 (MDR1) expression, enhancing intracellular doxorubicin accumulation, and decreasing P-glycoprotein efflux pump activity of ABC transporter family members (Liang et al., 2010).