Figure 2.

Models of the mammary epithelial hierarchy. (A). Differentiation of lobular-restricted and ductal-limited progenitors from pluripotent mammary epithelial stem/progenitor cells (serial transplantation model); adapted from [16] (2005). (B). Epithelial lineage hierarchy model based on the expression of integrins and other selected cellular markers using flow cytometry; adapted from [21]. (C). Continuous progression model based on transcriptomic changes and epigenetic states; adapted from [31].