Investigating the susceptibility of oestrogen receptor-positive (ER^pos) normal human breast epithelial cells (HBECs) for clinical purposes or basic research awaits a proficient cell-based assay.

Researchers set out to identify markers for isolating ER^pos cells and to expand what appear to be post-mitotic primary cells into exponentially growing cultures. They report a robust technique for isolating ER^pos HBECs from reduction mammoplasties by FACS using two cell surface markers, CD166 and CD117, and an intracellular cytokeratin marker, Ks20.8, for further tracking single cells in culture.

Authors show that ER^pos HBECs are released from growth restraint by small molecule inhibitors of TGFβ signalling, and that growth is augmented further in response to oestrogen.

 Importantly, ER signalling is functionally active in ER^pos cells in extended culture. These findings open a new avenue of experimentation with normal ER^pos HBECs and provide a basis for understanding the evolution of human breast cancer.

http://www.nature.com/ncomms/2015/151113/ncomms9786/full/ncomms9786.html