ATP-binding cassette (ABC) transporters have been identified as transporters of S1P in different cell lines, such as ABC subfamily C member 1 (ABCC1) in mast cells (Mitra et al., 2006), ABC subfamily A member 1 (ABCA1) in astrocytes (Sato et al., 2007), or ABCC1 and ABC subfamily G member 2 (ABCG2) in breast cancer cells (Takabe et al., 2010). The gene discussed is ABCC1; the disease is breast cancer.