ABCB1 and hepatocellular carcinoma: One study found that quercetin can reverse multidrug resistance (MDR) of HCC cells by down-regulating the expression of mdr1, multidrug resistance-associated protein (MRP), glutathione-S-transferase-π (GST-π), and H-ras, while also down-regulating P-glycoprotein expression (Wei et al., 2012).