ABCB1 and hepatocellular carcinoma: EGCG may reverse multidrug resistance mechanisms in hepatocellular carcinoma cells; it may inhibit the expression of the multiple drug resistance 1 (MDR1) gene or downregulate P-glycoprotein (P-gp), reducing P-glycoprotein-mediated drug pumping activity and causing intracellular doxorubicin accumulation [140].