ABCA1 and breast cancer: For example, ABCC1 (MRP1; multidrug-resistant protein 1) transports S1P from mast cells [48], ABCA1 from astrocytes [49], ABCA1 and ABCC1 from endothelial cells [50], and ABCC1 and ABCG2 from breast cancer cells as presented in Fig. 2 [51].