SLCO1B1 and breast cancer: Hepatocytes but not breast cancer cells express the OATP1B1 and 1B3 transporters responsible for statin cellular uptake.45 We have previously shown that atorvastatin is more effective than rosuvastatin at suppressing cancer cell growth.24,34 These data additionally suggest that the direct effects of statins on tumor cells play a larger role in proliferation suppression than indirect effects from statins influencing the neighboring hepatocytes.