Figure 1.

Epithelial lineages change as a function of age. (A) Representative FACS analyses of CD227 and CD10 expression in 4^th passage HMEC strains isolated from one woman <30years (195L) and one >55years (805P). FACS plots are shown as 5% contour plots with outliers identified, at left are isotype antibody controls, and at right are the CD10 and CD227 stained samples. Gates identifying luminal epithelial (LEP) and myoepithelial (MEP) are shown. (B) Linear regression showing changes in proportions of LEPs (green) and MEPs (red) in HMEC strains at 4^th passage as a function of age (n=36 individuals). LEPs and MEPs from reduction mammoplasty (RM)-derived strains are shown with filled circles or boxes, and from peripheral to tumor (P)-derived strains with open circles or boxes, respectively. (C) Representative FACS analyses from the corresponding uncultured dissociated epithelial organoids. FACS plots are shown as 5% contour plots with outliers identified, at left are isotype antibody controls, and at right are the CD10 and CD227 stained samples. (D) Linear regression of proportions of LEPs (green) and MEPs (red) in dissociated uncultured organoids as a function of age (n=8 individuals). LEPs and MEPs from RM-derived organoids are shown with filled circles or boxes, and from P-derived organoids with open circles or boxes, respectively. (E) Histograms of CD49f (integrin α6) expression by flow cytometry on CD227+ LEPs (green lines) and CD10+ MEPs (red lines) from dissociated organoids. The gray-colored shade boxes indicate the threshold at which there is little or no CD49f expression as determined in isotype negative control stains (gray lines). (F) Regression analysis of Log₂ change in mean expression of CD49f in LEPs normalized to the levels in MEPs from dissociated organoids as a function of age (n=8 individuals).