Furthermore, E1S uptake carrier expression was demonstrated in different hormone-dependent breast cancer cell lines, such as OATP1A2, OATP3A1, and OATP4A1 in T47D cells (Nozawa et al., 2004, 2005; Meyer zu Schwabedissen et al., 2008) as well as OATP1A2, OATP2B1, OATP3A1, and OATP4A1 in MCF7 cells (Nozawa et al., 2005; Meyer zu Schwabedissen et al., 2008; Wlcek et al., 2008; Maeda et al., 2010; Stute et al., 2012; Banerjee et al., 2012, 2013, 2015; Matsumoto et al., 2015). This evidence concerns the gene SLCO2B1 and breast carcinoma.