Figure 1.

ERα is strongly expressed in luminal progenitors. (A) Luminal (EpCAM^{brig ht} CD49f^low) and bipotent (EpCAM^lowCD49f^bright) progenitors were isolated from reduction mammoplasty samples using FACS. (B) CFC assays were used to determine the purity of different progenitor subtypes. As shown, 21.6% of the EpCAM^brightCD49f^low cells formed pure luminal colonies, whereas 16.7% of the EpCAM^low CD49f^bright cells formed mixed colonies (n=3). Representative luminal and mixed colonies are shown in the photographs.