LGR5 and breast cancer: Various BCSC markers were also identified from breast cancer cell lines such as MUC1 (also known as CA153) (24), Procr+/ESA+ (epithelial specific antigen) (25), DLL1+/DNER+ (delta-like canonical Notch ligand1/delta/notch-like EGF repeat containing) (26), GD2 (27), ANTXR1 (ANTXR cell adhesion molecule 1) (28), ABCG2 (ATP-binding cassette subfamily G member 2) (29), Lgr5 (leucine rich repeat containing G protein-coupled receptor 5) (30), SSEA-3 (stage-specific embryonic antigen-3) (31), Nectin-4 (nectin cell adhesion molecule 4) (32), and CD70 (33) (Table 1).