Figure 1

Schematic representation of differences between normal and malignant breast epithelial stem/progenitor subpopulations. Comparison of pie charts summarizing the differences and similarities between different epithelial cells within Ep-CAM/CD49f subpopulations, which were presented as subfractions based on stem/progenitor cell markers, in accordance with the data recently described in BMC Cancer [21]. The three epithelial cell populations of the normal breast (named A, B and C) are compared with their malignant counterparts, highlighting the peculiarity of each subpopulation. The schematic size of the mammosphere relates to the measured ability of mammosphere/colony-forming cells. Basal progenitor cells showed higher mammosphere colony-forming ability compared with luminal progenitor cells in normal breast cells (A>B, C = 0), whereas in BC, the luminal progenitor subpopulation showed increased ability to form mammospheres compared with differentiated luminal cells. Subpopulations: orange, Ep-CAM^low/CD49f⁺; yellow, Ep-CAM^high/CD49f⁺; green, Ep-CAM^high/CD49f^-.