ABCB1 and liver cancer: In Hep-3B liver cancer cells, RA (17.3–138.8 μM) was found to decrease cell viability [30], while treatment of HepG2 liver cancer cells with RA (20–80 μM) showed no significant changes to cell viability but an increase in Nrf2 nuclear translocation, ARE-luciferin activity, MRP2 levels, intracellular ATP levels and efflux of p-glycoprotein was seen [100].