SLCO1B3 and cancer: Whereas the primary variant, designated in this manuscript as Lt-OATP1B3 (liver-type OATP1B3), is expressed in healthy human hepatocytes, the Ct-OATP1B3 (cancer-type OATP1B3) variant is expressed mostly in tumorous tissues such as colorectal or pancreatic carcinoma [16,20,25].